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The EPIC Concept for the Inflation Probe
Shaul Hanany (Minnesota)
Adrian Lee (Berkeley) and Brian Keating (UCSD)
EPIC (Jamie Bock JPL)
Coherent Receiver Concept(Mike Seifert JPL)
NASA Mission Concept Studies 2004
bull CMBPol (Gary Hinshaw Goddard)
bull EPIC (Experimental Probe of Inflationary Cosmology Jamie Bock JPL)
(Astro-ph08054207)
bull EPIC (Einstein Polarization Interferometer for Cosmology Peter Timbie Wisconsin)
NASA Mission Concept Study 2008
Two Example Missions
bull BEPAC Reviews Concept Studies bull PPPDT (~82007) leads CMB community to a unified response to NASA Solicitation
Title Here
Experimental Probe of Inflationary Cosmology (EPIC)
Jamie BockJPL Caltech
U Chicago John Carlstrom Clem Pryke
U Colorado Jason Glenn
UC Davis Lloyd Knox
Dartmouth Robert Caldwell
Fermilab Scott Dodelson
IAP Ken Ganga Eric Hivon
IAS Jean-Loup Puget Nicolas Ponthieu
The EPIC ConsortiumCaltechIPAC Charles Beichman Sunil Golwala Marc Kamionkowski Andrew Lange Tim Pearson Anthony Readhead Jonas Zmuidzinas
UC BerkeleyLBNL Adrian Lee Carl Heiles Bill Holzapfel Paul Richards Helmut Spieler Huan Tran Martin White
Cardiff Walter Gear
Carnegie Mellon Jeff Peterson
JPL Peter Day Clive Dickenson Darren Dowell Mark Dragovan Todd Gaier Krzysztof Gorski Warren Holmes Jeff Jewell Bob Kinsey Charles Lawrence Rick LeDuc Erik Leitch Steven Levin Mark Lysek Sara MacLellan Hien Nguyen Ron Ross Celeste Satter Mike Seiffert Hemali Vyas Brett Williams
UC Irvine Alex Amblard Asantha Cooray Manoj Kaplinghat
U Minnesota Shaul Hanany Michael Milligan Tomotake Matsumura
NIST Kent Irwin
UC San Diego Brian Keating Tom Renbarger
Stanford Sarah Church
Swales Aerospace Dustin CrumbTC Technology Terry CaffertyUSC Aluizio Prata
(Astro-ph08054207)
Science Objective
Measurement Criteria Instrument Criteria
EPIC
COMPREHENSIVE
EPIC
LC
Inflationary Gravity Waves
Detect BB to r=001 after removal of
foregrounds
bull Wp-12 lt 6 μKarcmin
bull 30 ndash 300 GHz bandsbull Control systematics to negligible levelsbull All sky coveragebull Resolution lt 1 degree
Positively detect both ℓ=5 ℓ=100 peaks
Reionization
Cosm Parameters
EE to cosmic variance limit
Same as above + Moderate angular
resolution (~5rsquo)
Neutrino mass dark energy
map lensing shear
BB to cosmic variance limit
Galactic magnetic fields
Dust + Synchrotron polarization
Science Drivers
Recommended by Weiss Committee
EPIC is a Scan-Imaging Polarimeter
Scan Modulated Polarimeters Simple technique strong established history (maxipol boomerang bicep quad) EBEX Planck-HFI Clover Polarbearhellip
Background Limited Sensitivity in a Single Technology 30 ndash 300 GHz (or more) with bolometers
High Sensitivity ~x10 better than Planck Requires large focal plane arrays High throughput optical designs Control of Systematics Goal raw effects are x10 lower than statistical noise Requirement characterize effects such as to remove below r=001
Design Approach
EPIC = Study of Two Implementations
EPIC Low Cost (LC) EPIC Comprehensive Science (CS)
Delta II Mass 13 tons
L2 orbit
Atlas VMass 35 tons
L2 orbit
~35 m
LC CS
6 x 30 cm Telescopes Single 28 meter telescope
Frequencies 30 ndash 300 GHz 30 ndash 500 GHz
Resolution 09˚ at 90 GHz 46rsquo at 100 GHz
Detectors 2366 Bolometers 1520 Bolometers
Lifetime 2 years 4 years
Cost $660M No assessment done
~16 m
450 ℓ Liquid
Helium
8 m
EPIC Low-Cost Mission Architecture
155 K
100 K
40 K
295 K
EPIC - LC
Half-WavePlate (2 K)
PolyethyleneLenses (2 K)
Focal Plane Bolometer Array
30 cm
Six 30 cm Telescopes at 2 K
Telescope
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]e
1 3040 155116 854 370
2 60 77 128 69
3 90 52 512 30
4 90 52 512 30
5 135 34 512 28
6 200300 2316 576576 29
01 K bolometersNET = 12 μKradicsec
Weight-1 = 25 μKarcminΔTpix=16 nK
radic2 noise margin
Passively Cooled Mirrors
28 m
Receiver amp Lenses
20 m
EPIC - CS
155 K85 K
293 K
bull 01 K bolometersbull NET = 18 μKradicsecbull Weight-1 = 28 μKarcminbull ΔTpix=16 nK
bull radic2 noise margin
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]30 155 20 170
45 103 80 73
70 66 220 38100 46 320 29
150 31 380 28
220 21 280 47
340 14 120 220
500 09 100 1900
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC (Jamie Bock JPL)
Coherent Receiver Concept(Mike Seifert JPL)
NASA Mission Concept Studies 2004
bull CMBPol (Gary Hinshaw Goddard)
bull EPIC (Experimental Probe of Inflationary Cosmology Jamie Bock JPL)
(Astro-ph08054207)
bull EPIC (Einstein Polarization Interferometer for Cosmology Peter Timbie Wisconsin)
NASA Mission Concept Study 2008
Two Example Missions
bull BEPAC Reviews Concept Studies bull PPPDT (~82007) leads CMB community to a unified response to NASA Solicitation
Title Here
Experimental Probe of Inflationary Cosmology (EPIC)
Jamie BockJPL Caltech
U Chicago John Carlstrom Clem Pryke
U Colorado Jason Glenn
UC Davis Lloyd Knox
Dartmouth Robert Caldwell
Fermilab Scott Dodelson
IAP Ken Ganga Eric Hivon
IAS Jean-Loup Puget Nicolas Ponthieu
The EPIC ConsortiumCaltechIPAC Charles Beichman Sunil Golwala Marc Kamionkowski Andrew Lange Tim Pearson Anthony Readhead Jonas Zmuidzinas
UC BerkeleyLBNL Adrian Lee Carl Heiles Bill Holzapfel Paul Richards Helmut Spieler Huan Tran Martin White
Cardiff Walter Gear
Carnegie Mellon Jeff Peterson
JPL Peter Day Clive Dickenson Darren Dowell Mark Dragovan Todd Gaier Krzysztof Gorski Warren Holmes Jeff Jewell Bob Kinsey Charles Lawrence Rick LeDuc Erik Leitch Steven Levin Mark Lysek Sara MacLellan Hien Nguyen Ron Ross Celeste Satter Mike Seiffert Hemali Vyas Brett Williams
UC Irvine Alex Amblard Asantha Cooray Manoj Kaplinghat
U Minnesota Shaul Hanany Michael Milligan Tomotake Matsumura
NIST Kent Irwin
UC San Diego Brian Keating Tom Renbarger
Stanford Sarah Church
Swales Aerospace Dustin CrumbTC Technology Terry CaffertyUSC Aluizio Prata
(Astro-ph08054207)
Science Objective
Measurement Criteria Instrument Criteria
EPIC
COMPREHENSIVE
EPIC
LC
Inflationary Gravity Waves
Detect BB to r=001 after removal of
foregrounds
bull Wp-12 lt 6 μKarcmin
bull 30 ndash 300 GHz bandsbull Control systematics to negligible levelsbull All sky coveragebull Resolution lt 1 degree
Positively detect both ℓ=5 ℓ=100 peaks
Reionization
Cosm Parameters
EE to cosmic variance limit
Same as above + Moderate angular
resolution (~5rsquo)
Neutrino mass dark energy
map lensing shear
BB to cosmic variance limit
Galactic magnetic fields
Dust + Synchrotron polarization
Science Drivers
Recommended by Weiss Committee
EPIC is a Scan-Imaging Polarimeter
Scan Modulated Polarimeters Simple technique strong established history (maxipol boomerang bicep quad) EBEX Planck-HFI Clover Polarbearhellip
Background Limited Sensitivity in a Single Technology 30 ndash 300 GHz (or more) with bolometers
High Sensitivity ~x10 better than Planck Requires large focal plane arrays High throughput optical designs Control of Systematics Goal raw effects are x10 lower than statistical noise Requirement characterize effects such as to remove below r=001
Design Approach
EPIC = Study of Two Implementations
EPIC Low Cost (LC) EPIC Comprehensive Science (CS)
Delta II Mass 13 tons
L2 orbit
Atlas VMass 35 tons
L2 orbit
~35 m
LC CS
6 x 30 cm Telescopes Single 28 meter telescope
Frequencies 30 ndash 300 GHz 30 ndash 500 GHz
Resolution 09˚ at 90 GHz 46rsquo at 100 GHz
Detectors 2366 Bolometers 1520 Bolometers
Lifetime 2 years 4 years
Cost $660M No assessment done
~16 m
450 ℓ Liquid
Helium
8 m
EPIC Low-Cost Mission Architecture
155 K
100 K
40 K
295 K
EPIC - LC
Half-WavePlate (2 K)
PolyethyleneLenses (2 K)
Focal Plane Bolometer Array
30 cm
Six 30 cm Telescopes at 2 K
Telescope
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]e
1 3040 155116 854 370
2 60 77 128 69
3 90 52 512 30
4 90 52 512 30
5 135 34 512 28
6 200300 2316 576576 29
01 K bolometersNET = 12 μKradicsec
Weight-1 = 25 μKarcminΔTpix=16 nK
radic2 noise margin
Passively Cooled Mirrors
28 m
Receiver amp Lenses
20 m
EPIC - CS
155 K85 K
293 K
bull 01 K bolometersbull NET = 18 μKradicsecbull Weight-1 = 28 μKarcminbull ΔTpix=16 nK
bull radic2 noise margin
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]30 155 20 170
45 103 80 73
70 66 220 38100 46 320 29
150 31 380 28
220 21 280 47
340 14 120 220
500 09 100 1900
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Title Here
Experimental Probe of Inflationary Cosmology (EPIC)
Jamie BockJPL Caltech
U Chicago John Carlstrom Clem Pryke
U Colorado Jason Glenn
UC Davis Lloyd Knox
Dartmouth Robert Caldwell
Fermilab Scott Dodelson
IAP Ken Ganga Eric Hivon
IAS Jean-Loup Puget Nicolas Ponthieu
The EPIC ConsortiumCaltechIPAC Charles Beichman Sunil Golwala Marc Kamionkowski Andrew Lange Tim Pearson Anthony Readhead Jonas Zmuidzinas
UC BerkeleyLBNL Adrian Lee Carl Heiles Bill Holzapfel Paul Richards Helmut Spieler Huan Tran Martin White
Cardiff Walter Gear
Carnegie Mellon Jeff Peterson
JPL Peter Day Clive Dickenson Darren Dowell Mark Dragovan Todd Gaier Krzysztof Gorski Warren Holmes Jeff Jewell Bob Kinsey Charles Lawrence Rick LeDuc Erik Leitch Steven Levin Mark Lysek Sara MacLellan Hien Nguyen Ron Ross Celeste Satter Mike Seiffert Hemali Vyas Brett Williams
UC Irvine Alex Amblard Asantha Cooray Manoj Kaplinghat
U Minnesota Shaul Hanany Michael Milligan Tomotake Matsumura
NIST Kent Irwin
UC San Diego Brian Keating Tom Renbarger
Stanford Sarah Church
Swales Aerospace Dustin CrumbTC Technology Terry CaffertyUSC Aluizio Prata
(Astro-ph08054207)
Science Objective
Measurement Criteria Instrument Criteria
EPIC
COMPREHENSIVE
EPIC
LC
Inflationary Gravity Waves
Detect BB to r=001 after removal of
foregrounds
bull Wp-12 lt 6 μKarcmin
bull 30 ndash 300 GHz bandsbull Control systematics to negligible levelsbull All sky coveragebull Resolution lt 1 degree
Positively detect both ℓ=5 ℓ=100 peaks
Reionization
Cosm Parameters
EE to cosmic variance limit
Same as above + Moderate angular
resolution (~5rsquo)
Neutrino mass dark energy
map lensing shear
BB to cosmic variance limit
Galactic magnetic fields
Dust + Synchrotron polarization
Science Drivers
Recommended by Weiss Committee
EPIC is a Scan-Imaging Polarimeter
Scan Modulated Polarimeters Simple technique strong established history (maxipol boomerang bicep quad) EBEX Planck-HFI Clover Polarbearhellip
Background Limited Sensitivity in a Single Technology 30 ndash 300 GHz (or more) with bolometers
High Sensitivity ~x10 better than Planck Requires large focal plane arrays High throughput optical designs Control of Systematics Goal raw effects are x10 lower than statistical noise Requirement characterize effects such as to remove below r=001
Design Approach
EPIC = Study of Two Implementations
EPIC Low Cost (LC) EPIC Comprehensive Science (CS)
Delta II Mass 13 tons
L2 orbit
Atlas VMass 35 tons
L2 orbit
~35 m
LC CS
6 x 30 cm Telescopes Single 28 meter telescope
Frequencies 30 ndash 300 GHz 30 ndash 500 GHz
Resolution 09˚ at 90 GHz 46rsquo at 100 GHz
Detectors 2366 Bolometers 1520 Bolometers
Lifetime 2 years 4 years
Cost $660M No assessment done
~16 m
450 ℓ Liquid
Helium
8 m
EPIC Low-Cost Mission Architecture
155 K
100 K
40 K
295 K
EPIC - LC
Half-WavePlate (2 K)
PolyethyleneLenses (2 K)
Focal Plane Bolometer Array
30 cm
Six 30 cm Telescopes at 2 K
Telescope
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]e
1 3040 155116 854 370
2 60 77 128 69
3 90 52 512 30
4 90 52 512 30
5 135 34 512 28
6 200300 2316 576576 29
01 K bolometersNET = 12 μKradicsec
Weight-1 = 25 μKarcminΔTpix=16 nK
radic2 noise margin
Passively Cooled Mirrors
28 m
Receiver amp Lenses
20 m
EPIC - CS
155 K85 K
293 K
bull 01 K bolometersbull NET = 18 μKradicsecbull Weight-1 = 28 μKarcminbull ΔTpix=16 nK
bull radic2 noise margin
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]30 155 20 170
45 103 80 73
70 66 220 38100 46 320 29
150 31 380 28
220 21 280 47
340 14 120 220
500 09 100 1900
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Science Objective
Measurement Criteria Instrument Criteria
EPIC
COMPREHENSIVE
EPIC
LC
Inflationary Gravity Waves
Detect BB to r=001 after removal of
foregrounds
bull Wp-12 lt 6 μKarcmin
bull 30 ndash 300 GHz bandsbull Control systematics to negligible levelsbull All sky coveragebull Resolution lt 1 degree
Positively detect both ℓ=5 ℓ=100 peaks
Reionization
Cosm Parameters
EE to cosmic variance limit
Same as above + Moderate angular
resolution (~5rsquo)
Neutrino mass dark energy
map lensing shear
BB to cosmic variance limit
Galactic magnetic fields
Dust + Synchrotron polarization
Science Drivers
Recommended by Weiss Committee
EPIC is a Scan-Imaging Polarimeter
Scan Modulated Polarimeters Simple technique strong established history (maxipol boomerang bicep quad) EBEX Planck-HFI Clover Polarbearhellip
Background Limited Sensitivity in a Single Technology 30 ndash 300 GHz (or more) with bolometers
High Sensitivity ~x10 better than Planck Requires large focal plane arrays High throughput optical designs Control of Systematics Goal raw effects are x10 lower than statistical noise Requirement characterize effects such as to remove below r=001
Design Approach
EPIC = Study of Two Implementations
EPIC Low Cost (LC) EPIC Comprehensive Science (CS)
Delta II Mass 13 tons
L2 orbit
Atlas VMass 35 tons
L2 orbit
~35 m
LC CS
6 x 30 cm Telescopes Single 28 meter telescope
Frequencies 30 ndash 300 GHz 30 ndash 500 GHz
Resolution 09˚ at 90 GHz 46rsquo at 100 GHz
Detectors 2366 Bolometers 1520 Bolometers
Lifetime 2 years 4 years
Cost $660M No assessment done
~16 m
450 ℓ Liquid
Helium
8 m
EPIC Low-Cost Mission Architecture
155 K
100 K
40 K
295 K
EPIC - LC
Half-WavePlate (2 K)
PolyethyleneLenses (2 K)
Focal Plane Bolometer Array
30 cm
Six 30 cm Telescopes at 2 K
Telescope
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]e
1 3040 155116 854 370
2 60 77 128 69
3 90 52 512 30
4 90 52 512 30
5 135 34 512 28
6 200300 2316 576576 29
01 K bolometersNET = 12 μKradicsec
Weight-1 = 25 μKarcminΔTpix=16 nK
radic2 noise margin
Passively Cooled Mirrors
28 m
Receiver amp Lenses
20 m
EPIC - CS
155 K85 K
293 K
bull 01 K bolometersbull NET = 18 μKradicsecbull Weight-1 = 28 μKarcminbull ΔTpix=16 nK
bull radic2 noise margin
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]30 155 20 170
45 103 80 73
70 66 220 38100 46 320 29
150 31 380 28
220 21 280 47
340 14 120 220
500 09 100 1900
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC is a Scan-Imaging Polarimeter
Scan Modulated Polarimeters Simple technique strong established history (maxipol boomerang bicep quad) EBEX Planck-HFI Clover Polarbearhellip
Background Limited Sensitivity in a Single Technology 30 ndash 300 GHz (or more) with bolometers
High Sensitivity ~x10 better than Planck Requires large focal plane arrays High throughput optical designs Control of Systematics Goal raw effects are x10 lower than statistical noise Requirement characterize effects such as to remove below r=001
Design Approach
EPIC = Study of Two Implementations
EPIC Low Cost (LC) EPIC Comprehensive Science (CS)
Delta II Mass 13 tons
L2 orbit
Atlas VMass 35 tons
L2 orbit
~35 m
LC CS
6 x 30 cm Telescopes Single 28 meter telescope
Frequencies 30 ndash 300 GHz 30 ndash 500 GHz
Resolution 09˚ at 90 GHz 46rsquo at 100 GHz
Detectors 2366 Bolometers 1520 Bolometers
Lifetime 2 years 4 years
Cost $660M No assessment done
~16 m
450 ℓ Liquid
Helium
8 m
EPIC Low-Cost Mission Architecture
155 K
100 K
40 K
295 K
EPIC - LC
Half-WavePlate (2 K)
PolyethyleneLenses (2 K)
Focal Plane Bolometer Array
30 cm
Six 30 cm Telescopes at 2 K
Telescope
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]e
1 3040 155116 854 370
2 60 77 128 69
3 90 52 512 30
4 90 52 512 30
5 135 34 512 28
6 200300 2316 576576 29
01 K bolometersNET = 12 μKradicsec
Weight-1 = 25 μKarcminΔTpix=16 nK
radic2 noise margin
Passively Cooled Mirrors
28 m
Receiver amp Lenses
20 m
EPIC - CS
155 K85 K
293 K
bull 01 K bolometersbull NET = 18 μKradicsecbull Weight-1 = 28 μKarcminbull ΔTpix=16 nK
bull radic2 noise margin
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]30 155 20 170
45 103 80 73
70 66 220 38100 46 320 29
150 31 380 28
220 21 280 47
340 14 120 220
500 09 100 1900
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC = Study of Two Implementations
EPIC Low Cost (LC) EPIC Comprehensive Science (CS)
Delta II Mass 13 tons
L2 orbit
Atlas VMass 35 tons
L2 orbit
~35 m
LC CS
6 x 30 cm Telescopes Single 28 meter telescope
Frequencies 30 ndash 300 GHz 30 ndash 500 GHz
Resolution 09˚ at 90 GHz 46rsquo at 100 GHz
Detectors 2366 Bolometers 1520 Bolometers
Lifetime 2 years 4 years
Cost $660M No assessment done
~16 m
450 ℓ Liquid
Helium
8 m
EPIC Low-Cost Mission Architecture
155 K
100 K
40 K
295 K
EPIC - LC
Half-WavePlate (2 K)
PolyethyleneLenses (2 K)
Focal Plane Bolometer Array
30 cm
Six 30 cm Telescopes at 2 K
Telescope
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]e
1 3040 155116 854 370
2 60 77 128 69
3 90 52 512 30
4 90 52 512 30
5 135 34 512 28
6 200300 2316 576576 29
01 K bolometersNET = 12 μKradicsec
Weight-1 = 25 μKarcminΔTpix=16 nK
radic2 noise margin
Passively Cooled Mirrors
28 m
Receiver amp Lenses
20 m
EPIC - CS
155 K85 K
293 K
bull 01 K bolometersbull NET = 18 μKradicsecbull Weight-1 = 28 μKarcminbull ΔTpix=16 nK
bull radic2 noise margin
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]30 155 20 170
45 103 80 73
70 66 220 38100 46 320 29
150 31 380 28
220 21 280 47
340 14 120 220
500 09 100 1900
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
450 ℓ Liquid
Helium
8 m
EPIC Low-Cost Mission Architecture
155 K
100 K
40 K
295 K
EPIC - LC
Half-WavePlate (2 K)
PolyethyleneLenses (2 K)
Focal Plane Bolometer Array
30 cm
Six 30 cm Telescopes at 2 K
Telescope
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]e
1 3040 155116 854 370
2 60 77 128 69
3 90 52 512 30
4 90 52 512 30
5 135 34 512 28
6 200300 2316 576576 29
01 K bolometersNET = 12 μKradicsec
Weight-1 = 25 μKarcminΔTpix=16 nK
radic2 noise margin
Passively Cooled Mirrors
28 m
Receiver amp Lenses
20 m
EPIC - CS
155 K85 K
293 K
bull 01 K bolometersbull NET = 18 μKradicsecbull Weight-1 = 28 μKarcminbull ΔTpix=16 nK
bull radic2 noise margin
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]30 155 20 170
45 103 80 73
70 66 220 38100 46 320 29
150 31 380 28
220 21 280 47
340 14 120 220
500 09 100 1900
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Passively Cooled Mirrors
28 m
Receiver amp Lenses
20 m
EPIC - CS
155 K85 K
293 K
bull 01 K bolometersbull NET = 18 μKradicsecbull Weight-1 = 28 μKarcminbull ΔTpix=16 nK
bull radic2 noise margin
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]δTpix
[nK]30 155 20 170
45 103 80 73
70 66 220 38100 46 320 29
150 31 380 28
220 21 280 47
340 14 120 220
500 09 100 1900
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
70 GHz65 of sky
EPIC-LC2 year
Δℓℓ=03
Planck12 yearΔℓℓ=03
WMAP8 year
Δℓℓ=03
No foreground subtraction No systematic uncertainties
EPIC-CS4 year
Δℓℓ=03
Comparison of Raw Sensitivity
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Two EBEX Wafers (~1500 TES Bolometers )
EPIC Bolometer Sensitivity already Achieved
Courtesy of Jonas Zmuidzinas
EPIC GoalDetector Sensitivity
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
SCUBA2 Focal Plane (10000 TES Bolometers)
BICEP-II (512 TEPS Bolometers)Two EBEX Wafers (~1500 TES Bolometers )
One SPT Wafer (~1000 TES Bolometers)
BackACT one of 3 32x32 arrays
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Redundant amp Uniform Scan CoverageEPIC Low-Cost Mission ArchitectureForeground Removal for EPIC-LC
bull Only dust + synchrotron
bull ℓ space subtraction
(Amblard et al 2007)
bull Dust + synch correlations from simulations
bull Polarization amplitude = 5 of dust intensity (model 8) or from synch
bull Polarization orientation = synchrotron traces B field
Can reach r=0003 (99 binned 2ltℓlt100)
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Systematic Error Study
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Main beam Effects ndash Instrumental Polarization
Δ Beam Size FWHMEneFWHMH lt4 x 10-5
HWP in frontRefractor
Scan crossings
Δ gain GEneGH lt10-4
Δ Beam Offset PointEnePointH lt014rdquo
Δ Ellipticity eEneeH lt6 x 10-6
Sat Pointing Q U Offset lt012rdquo Gyro + tracker
Main beam Effects ndash Cross Polarization
Δ Rotation E H not orthogonal lt4rsquo HWP in frontMeasure and
SubtractPixel rotation EH rotated lt24rsquo
Opt Cross Pol Birefringence lt10-4
Scan Synchronous Signals
Sidelobes Diffraction Scattering
lt1 nK
Refractor + Baffle
Thermal drift Sun viewing angle Thermal design
Magnetic Pickup TES SQUID susceptibility ShieldingAchieved Requires spaceTested by sub-orbital experiments
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC-LC Systematic Error Mitigation
Systematic Description Goal Mitigation
Thermal Stability
40 K Baffle
Varying power from thermal emission
5 mKradicHz
5 μK ss
Temperature Control2 K Optics 500 μKradicHz
1 μK ss
01 K Focal Plane Thermal signal induced in detectors
200 nKradicHz 05 nK ss
Other
1f Noise Detector + readout gain drift
0016 Hz Demonstrate or faster scan or
modulate HWP
Passband Mismatch Variation in Filters Δνcνclt10-4 Measure to required
level
Gain Error Relative responsivity uncertainty
Δνcνclt10-4 Orbit-modulated dipole
Achieved Requires spaceTested by sub-orbital experiments
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Spin A
xis
(~1
rpm
)
Sun-Spacecraft Axis (~03 rph)
Op
tica
l Axi
s
Sun Earth
Moon
SE L2
45deg55deg
Orbit
Why Space
- All-Sky Coverage - High Sensitivity - Systematic Error Control - Broad Frequency Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 m
inu
te3
min
ute
s1
ho
ur
Scan Coverage
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Scan Strategy
Sun-Spacecraft Axis
45˚
DownlinkTo Earth
Spin A
xis
(~1
rpm
)
Op
tica
l Axi
s
Precession(~1 rph)
55˚
1 Day Maps
Spatial Coverage
Angular Uniformity
More than half the sky in a single day
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Redundant amp Uniform Scan Coverage
Planck
WMAP
EPIC
N-hits (1-day) Angular Uniformity (6-months)
ltcos 2βgt2 + ltsin 2βgt2 0 1
EPIC Low-Cost Mission ArchitectureScan Strategy
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
BICEP Measurements Sky at 100 GHz
Levels below 3 nK for most of the sky
Far-Sidelobe Performance
~ 20 polarized
3nK
10
100
30
1 microK
10
100
1e3
1e4
1e5
Sidelobe Map at 100 GHz
BICEP Sidelobe Performance
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC Polarization Modulators
bull EPIC-LC ndash 6 single-band stepped HWPsndash 45˚ Steps every 24 hours
ndash Upscope continuous HWP
bull EPIC-C ndash Focal Plane Modulators
90 GHz Band
200300 GHz Band
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC Systematics Survey
bull Brian Keating Meir Shimon Nicolas Ponthieu Eric Hivon amp Jamie Bock
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
bull EPIC SystematicsMission Concept Study
Bock et al -- astro-ph 08054207)bull Simulated both 5rsquo ldquoLow Costrdquo and 60rsquo ldquoCSrdquo missions
bull Largely based on Shimon Keating Ponthieu amp Hivon 2008 (PRD v77)
bull Found excellent agreement with map-domain approach (Ponthieu amp Hivon)
bull Have adapted EPIC pipeline for effects on secondary science as well as primary B modes (Miller Shimon amp Keating astro-ph08063096)
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Systematic effects in real space
differential FWHM (monopole effect)
differential beam offset (dipole IP effect)
differential ellipticity (quadrupole effect)
differential gain (monopole effect)
Irreducible
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Definitions
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Scaling Laws
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Spin Classification of Systematics
bull The various spin characteristics and the mismatch with the required quadrupole allude to the role of scanning strategy
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Irreducible Beam SystematicDifferential Ellipticity
Diff ellipticity
For an unpolarized point source
-
=
T1 T2
Intrinsic on the sky
-
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
B-Mode Polarization (1deg) Differential Ellipticity (Inst Polarization)
e
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
B-Mode Polarization (1deg) Differential Rotation (Cross Polarization)
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Reducible Beam SystematicDifferential Pointing (Instrumental Polarization)
Diff pointing
For an unpolarized point source
=
T1 T2
-
NB Both Differential ellipticity and pointing have an orientation angle which determines what fraction is converted to E or B
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC Pipeline Comparison
Map-domain (Ponthieu amp Hivon)
Frequency Domain(Shimon Keating Miller)
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Requirements and Goals - LC Results
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
37 37
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Uniformity of Scan Strategy
K Gorski Ponthieu Hivon
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Systematic Error Mitigation
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Post-scanning Idealization
bull Differential gain beamwidth couple to the quadrupole of the scanning strategy
bull Differential pointing couples to the dipolebull Experiments with reasonable scanning
can benefit from throwing out the dipole and quadrupole from the data
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
ideal
Scan Strategy Issues amp EPIC Work TBD
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
ideal
Removing the dipole
ldquoRemoving the dipole refers to the multipoles of the scanning strategy NOT to be confused with the dipolersquorsquo and ldquoquadrupolerdquo beam systematic effect
Removing the dipole of the scanning strategy eliminates the first order pointing error
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
ideal
Removing the
quadrupole
bullRemoving the quadrupole asymmetry from the scanning strategy eliminates the differential gain and differential beamwidth effects
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
ldquoMediumrdquo Scale Mission
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
EPIC Challenges
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
In Search of an Optimum
EPIC ndash LC(30 cm aperture)
EPIC ndash CS(~3 meter aperture)
CostScientific Scope
Beam Effects Scan Speed vs Stability
Multichroic Refracting optics
How to Broaden Scientific Scope with
Minimal Cost Increase
What is the Optimal Angular
Resolution
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
A 2 meter Mission Concept
bull 01 K TEPS bolometersbull NET = 16 μKradicsecbull Weight = 25 μKarcminbull ΔTpix=15 nK
bull radic2 noise marginbull No Waveplate =gt focal
plane modulators
Single ~2 meter aperture
Frequencies 30 ndash 850 GHz
Resolution 8rsquo at 100 GHz
Detectors 1620 Bolometers
Lifetime 4 years
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]
30 26 20
45 17 80
70 11 220
100 8 320
150 5 380
220 35 280
340 23 120
500 15 100
850 09 100 Galactic Science Band
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Freq[GHz]
θFWHM
[arcmin]
Nbol
[]AΩband
[cm2 sr]a
AΩmaxband
[cm2 sr]b
NET [microKradics] wp-12
[microK-arcmin]
δTpix
[nK]bolo band
30 26 20 80 2000 78 18 27 160
45 17 80 150 960 66 73 11 66
70 11 220 170 480 55 37 57 34
100 8 320 120 310 49 27 42 25
150 5 380 60 140 47 24 37 22
220 35 280 20 70 51 31 47 28
340 23 120 4 15 82 75 12 68
500 15 100 15 5 220 22 34 (02)f 200
850 09 100 05 08 4500 450 690 (004)f 4000
Total 1620 610 14 21 12
Focal plane temperature T0 01 K Optical efficiency ηopt 40
Lens temperature Tlens 4 K Fractional bandwidth Δνν 30
Mirror temperature Topt 4 K Noise margin 1414
Mirror emissivity at 1 mm ε 10 Mission lifetime Tlife 4 years
Bolometer pitch dfλ 325 TES safety factor PsatQ 5
Sensitivity Numbers for Science Workshop 2 m
aFocal plane is nested with highest frequency bands in center lowest frequency bands at edge bTotal unabberated throughput if entire telescope uses one band onlycSensitivity of one bolometer (TCMB) in combined band using 2 bolometers per pixeldwp
-12 = [8π NETbolo2(Tmis Nbol)]12 (10800π)
eSensitivity δTCMB in a 2˚ x 2˚ pixel (1σ)fPoint source sensitivity in mJy (1σ) per beam without confusion
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Summary
bull EPIC ndash two ( three) realizations of a CMB inflation probe
bull Need input on ndash Optimization of angular resolution vs science deliverables
bull Neutrino mass limit vs angular resolution (or weight)bull Dark energy constraints vs angular resolution (or weight)bull Ancillary science vs angular resolution frequency coveragebull hellip
ndash Sensitivitybull How much is good enough Do we need more
ndash Frequency Coveragebull Is a 300 GHz band necessary bull Is a 30 GHz band necessary
ndash Is a very precise temperature measurement important bull eg Non-gaussianity
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations
Systematic Error Conclusionsbull Some experimental approaches are generically good modulate
polarization wout modulating beam shape low 1f noise low polarization rotation through optics low sidelobes
bull In reality different instrument designs trade-off between different sources of systematic errors
bull many sources are instrument + scan strategy specific and they Interact in a complicated way with overall design
bull Not clear that the issue of systematic errors gives preference for one design over another
bull All designs will require careful analysis of calibration and systematic error mitigation
bull To date no CMB experiment has fallen short of expectations because of systematic limitations