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Telescopes: SNO and the New SNOLAB. 2 km underground in Vale-INCO’s Creighton Mine near Sudbury, Ontario. Neutrino Telescopes Venice March 10, 2009 (Galileo + 400). Art McDonald Queen’s University, Kingston For the SNO Collaboration. The Sudbury Neutrino Observatory: SNO. - PowerPoint PPT Presentation
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Telescopes: SNO and the New SNOLAB
Art McDonaldQueen’s University, Kingston
For the SNO Collaboration
2 km underground in Vale-INCO’s CreightonMine near Sudbury, Ontario
Neutrino TelescopesVenice
March 10, 2009(Galileo + 400)
Acrylic vessel (AV) 12 m diameter
1700 tonnes H2O inner shielding
1000 tonnes D2O($300 million)
5300 tonnes H2O outer shielding
~9500 PMT’s
Creighton mineSudbury, CA
The Sudbury Neutrino Observatory: SNO6800 feet (~2km) underground
The heavy water has been returned and development work is in progress on SNO+ with liquid scintillator and 150Nd additive.
- Entire detectorBuilt as a Class 2000
Clean room- Low RadioactivityDetector materials
Bahcall et al.
, SNO
SNO: Solving the “Solar Neutrino Problem”Solar Model Flux Calculations
CNO
SNO was designed to observe separately e and all neutrino types to determine if low e fluxes come from solar models or neutrino flavor change (New Physics)
Previous Experiments Sensitive Mainly to Electron Neutrinos
Unique Signatures in SNO (D2O)
Charged-Current (CC)e+d e-+p+pEthresh = 1.4 MeV
ee onlyonly
Elastic Scattering (ES) (D2O & H2O)x+e- x+e-
x, but enhanced for e Events point away from the sun.
Neutral-Current (NC) x+d x+n+p Ethresh = 2.2 MeV
Equally sensitive to Equally sensitive to e e
3 ways todetect neutrons
Phase II (salt)July 01 - Sep. 03
Phase III (3He)Nov. 04-Dec. 06
Phase I (D2O)Nov. 99 - May 01
SNO: 3 neutron (NC) detectionmethods (systematically different)
n captures on2H(n, )3H
Effc. ~14.4% NC and CC separation by energy, radial, and
directional distributions
40 proportional counters
3He(n, p)3HEffc. ~ 30% capture
Measure NC rate with entirely different
detection system.
2 t NaCl. n captures on35Cl(n, )36ClEffc. ~40%
NC and CC separation by event isotropy
36Cl
35Cl+n 8.6 MeV
3H
2H+n 6.25 MeV
n + 3He p + 3H
p3H
5 cm
n
3He
ijijijij
ii
i
τττ
μμμ
eee
li
sandcwhere
e
e
cs
sc
iδecs
sccs
sc
UUU
UUU
UUU
U
sin,cos
00
00
001
0
010
0
00
010
001
0
0
001
100
0
0
2/
2/
1313
1313
2323
23231212
1212
321
321
321
3
2
ilil U If neutrinos have mass:
)E
LΔm.(θ)νP(ν eμ
222 271sin2sin
For 3 Active neutrinos. (MiniBoone has recently ruled out LSND result)
Solar,Reactor Atmospheric
As of today: Oscillation of 3 massive active neutrinos is clearly the dominant effect:
For two neutrino oscillation in a vacuum: (a valid approximation in many cases)
CP Violating Phase Reactor, Accel. Majorana Phases
Range defined for m12, m23
Maki-Nakagawa-Sakata-Pontecorvo matrix
(Double decay only)?
??
Leptogenesis: or phases -> possible matter/antimatter asymmetry in Early Universe
Matter Effects – the MSW effect
x
e
x
e Hdt
di
cos2θ
4E
Δmsin2θ
4E
Δm
sin2θ4E
ΔmNG2cos2θ
4E
Δm
H 22
2
eF
2
2
22
22
/2
2sin)2cos(
2sin2sin
mENG eF
m
The extra term arises because solar e have an extra interaction via W exchange with electrons in the Sun or Earth.
In the oscillation formula:
(Mikheyev, Smirnov, Wolfenstein)
MSW effect can produce an energy spectrum distortion and flavor regeneration in Earth giving a Day-night effect.If observed, matter interactions define the mass heirarchy.
)syst.()stat.( 35.2
)syst.()stat.( 94.4
)syst.()stat.( 68.1
15.015.0
22.022.0
38.034.0
21.021.0
08.009.0
06.006.0
ES
NC
CC
)scm10 of units(In 126
029.0031.0)stat.(023.034.0
NC
CC
The Total Flux of Active Neutrinos agrees
reasonably well with solar models:
5.95 (1+- 0.11) [BPS08 (GS)]
4.72 (1+- 0.11) [BPS08 (AGS)]
However, metal abundances, mixing …?
-> CNO measurements: Haxton, Serenelli
SNO Results for Salt Phase
Flavor change determined by > 7
Electron Neutrinos are only 1/3 of Total
-The solar results are best fit with the MSW effect and define the mass hierarchy (m2 > m1) through the Matter interaction.
-SNO: CC/NC flux defines tan2 < 1 (ie Non - Maximal mixing) by more than 5 standard deviations
SolarNeutrinos(SNO plus others)
Reactor Anti-Neutrinos(KAMLAND)
Final Phase: SNO Phase III
• Improve solar neutrino flux by breaking the CC and NC correlation:
CC: Cherenkov Signal PMT Array NC: n+3He NCD Array
• Improvement in 12, as
Neutral-Current Detectors (NCD): An array of 3He proportional counters:40 strings on 1-m grid: ~440 m
Phase III production data taking Dec 2004 to Dec 2006. D2O and NCD’s now removed.
NCD’s to be used in HALO: a lead-based Supernova detector for e
122sin
NC
CC
Neutrons from solar neutrino interactions
NC Signal:983 ± 77
Neutron background:185 ± 25
Alphas and Instrumentals:6126 ± 250(0.4 to 1.4 MeV)
SNO PAPER: arXiv:0806.0989v3 [nucl-ex] Phys.Rev.Lett.101:111301,2008
~ 1 alpha background event per month per meter of detector.
NCD Simulation Results data
MC Energy (MeV)
Energy (MeV)
Puls
e W
idth
(nns)
Puls
e W
idth
(nns)
full model of detector physicsto simulate pulse shape
characteristics, correlations
tuned on calibration data
neutron signal
alpha backgrounds:surface polonium decaybulk U and Th decay wire polonium decaywire bulk decayinsulator polonium decayinsulator bulk U and Th decay
stat stat + systSNO Fluxes: 3 Phases
p-value for consistency of NC/CC/ES in the salt & NCD phases + D2O NC(unconstr) is 32.8%
This work:• SNO NCD results agree well with previous SNO phases. Minimal correlation with CC. Different systematics.• New precision on
Future solar analysis: • LETA (Low Energy Threshold Analysis)• 3-neutrino analysis• hep flux• Day-night, other variations
• Muons, atmospheric
Solar + KamLAND fit results
519.021.0
2 1059.7 m eV2
degrees3.12.112 4.34
%)7~(1091.4 126
8 scmB
4.22.212 9.33
deg (previous)
Neutrino flavour symmetry phenomenology: (Smirnov summary at Neutrino 2008)Tri-Bi-Maximal Mixing: 35.2 degQuark-Lepton Complementarity: 32.2 deg(12 + Cabbibo = 45 deg)
The accuracy on and 8B will improve with new data analysis: SNO LETA
SNO Physics (Telescope) Program Solar Neutrinos (7 papers to date)
Electron Neutrino Flux Total Neutrino Flux Electron Neutrino Energy Spectrum Distortion Day/Night effects hep neutrinos hep-ex 0607010 Periodic variations: [Variations < 8% (1 dy to 10 yrs)] hep-ex/0507079
Atmospheric Neutrinos & Muons (arXiv: hep-ex 0902.2776) Downward going cosmic muon flux Atmospheric neutrinos: wide angular dependence [Look above horizon]
Supernova Watch (SNEWS) Limit for Solar Electron Antineutrinos
hep-ex/0407029 Nucleon decay (“Invisible” Modes: N ) Phys.Rev.Lett. 92 (2004) [Improves limit by 1000] Supernova Relic Electron Neutrinos hep-ex 0607010
X
SNO
Super-K
SNO provides a test of the Super-Kamiokande oscillation parameters (m2 = 2.1 x 10-3 ev2, sin22 = 1.00 +- 0.032). SNO: 2.6 x 10-3 ev2
SNO also provides a measure of the cosmic neutrino flux above the horizon. Normalization of Bartol 3-D atmospheric neutrino flux model: 1.22 +- 0.10.
SNO Muon & Atmospheric Neutrino Analysis
Through-going muons
SNO data for downward-going muons extends the previous data to about 13.5 km of water equivalent, where atmospheric neutrino generated muons begin to contribute significantly.Also studying neutron productionFrom muons.
New SNO paper arXiv: hep-ex 0902.2776
Downward-going Muons
New AV Hold Down Ropes
ExistingAV SupportRopes
The organicliquid is lighterthan water sothe Acrylic Vesselmust be held down.
New scintillator purification systems are required.
SNO+ : Liquid Scintillator with Nd for Double Beta Decay + Solar, geo -
Otherwise, the existing detector, electronics etc. are unchanged.
1000 tonnes of liquid scintillator (LAB)
(plus 1 tonne of natural Nd = 56 kg of 150Nd for Double BetaDecay)
• Nd is one of the most favorable double beta decay candidates with large phase space due to high endpoint: 3.37 MeV.
• Ideal scintillator (Linear Alkyl Benzene) has been identified. More light output than Kamland, Borexino, no effect on acrylic.
• Nd metallic-organic compound has been demonstrated to have long attenuation lengths, stable for more than 2 years.
• 1 tonne of Nd will cause very little degradation of light output. (Successful test in 2008 with small chamber in center of SNO)
• Isotopic abundance 5.6% (in SNO+ 1 tonne Nd = 56 kg 150Nd) • Possible enrichment of 150Nd or increase in the amount of natural
Nd.• SNO+ Capital proposal submitted, decision June 2009. • Plan to start with natural Nd in 2011.• Other physics: CNO solar neutrinos, pep solar neutrinos to study
neutrino properties, geo-neutrinos, supernova search.(No 11C background at this depth.)
SNO+: Neutrino-less Double Beta Decay: 150Nd
Queen’s, Alberta, Laurentian, SNOLAB, BNL, Washington, Penn, Texas, LIP Lisbon, Idaho State, Idaho Nat Lab, Oxford, Sussex, TUDresden, Leeds,UCLondon
Backgrounds assumed at Kamland observed values plus their purificationobjectives for 210Bi, 40K. Negligible background from 11C at SNOLAB depth.
Capability for 3 Years of Data
pep
CNO
Solar Neutrinos
m
(
eV)
Lightest neutrino (m1) in eV
m = |i Uei ² mi |
m = |m1 cos213cos²12 + m2 e2i cos213sin²12 + m3 e2i sin²13|
Measuring Effective Mass
normal hierarchy inverted hierarchy
SNO+ Sensitivity (3 years): 0.1 eV with 1 tonne natural Nd0.04 with 500 kg 150Nd.
Inverted
Normal
Present Expts.
0.04 eV
Mass Hierarchies
Normal Inverted
Degenerate
0: For example: 1057 events per year with 500 kg 150Nd-loaded liquid scintillator in SNO+.
Simulationassuming lightoutput and backgroundsimilar to Kamland.(Borexino has done better)
SNO+ (150Nd - less Double Beta Decay)
One year of datam= 0.15 eV
Sensitivity Limits (3 yrs): 1000 kg natural Nd (56 kg isotope): m ~ 0.1 eV (start 2011)With 500 kg enriched 150Nd: m ~ 0.04 eV
U ChainTh Chain
~Flat 8B Solar “background”
event rates:• KamLAND: 33 events per year (1000 tons CH2) / 142 events reactor• SNO+: 44 events per year (1000 tons CH2) / 42 events reactor
Geo-Neutrino Signal
SNO+ geo-neutrinos and reactor background
- four times smaller reactor background in the geo-neutrino region than in KamLAND- test models in a region dominated by crustal components.- very well characterized local geology enables residuals to probe the U and Th content of the deep Earth- reactor spectrum “dip” helps constrain m2 and 12
Letters of Intent/Interest (Red implies approval for siting) :Dark Matter:Timing of Liquid Argon/Neon Scintillation: DEAP-1 (7 kg), MINI-CLEAN (360 kg),
DEAP/CLEAN (3.6 Tonne)
Freon Super-saturated Gel: PICASSO
Silicon Bolometers: SUPER-CDMS (25 kg)
Double Beta Decay:150Nd: In liquid scintillator in SNO+
136Xe: EXO (Gas or Liquid) (Longer Term)
CdTe: COBRA (Longer Term)
Solar Neutrinos:Liquid Scintillator: SNO+ (also Reactor Neutrinos, Geo-neutrinos)
SuperNovae:SNO+: Liquid scintillator;
HALO: Pb plus SNO 3He detectors.
SNOLAB Construction is complete – Final cleaning occurring
SNOLAB @ Neutrino 2008 Christchurch May 28th, 2008
SNOLAB
Personnel facilities
SNO Cavern
Ladder Labs
Cube Hall
Phase IICryopit
UtilityArea
2009: MiniCLEAN 3602010: DEAP/CLEAN 3600
Now:DEAP-1
2010: SNO+
2009: HALO
Now:PICASSO-II
New large scale project.
2011: SuperCDMS ?
2010: PICASSO IIB?2010: EXO-200-Gas?
All Lab Air: Class < 2000
PersonnelFacility
LunchRoom
LunchRoom
Start of Clean conditions for the new SNOLAB: Feb. 2009
Cube Hall
MiniCLEAN360 kg2009
DEAP/CLEAN3.6 tonne
2010
Dark Matter Search with Liquid Argon: DEAP-1 (7 kg Ar) (Running); Future: Mini-Clean (360 kg Ar or Ne) and DEAP-3600 (3.6 tonnes Ar)
WIMP-Induced Nuclear recoils in Ar are discriminated from beta and gamma radioactivity (39Ar) by timing of the light emitted.
Dark Matter Search at SNOLAB with Liquid Argon
Yellow: Prompt light regionBlue: Late light region
)s9(TotalPE
)ns150(omptPEPrFprompt
Backgrounds (’s)
Signal (nuclear recoil)
DEAP-1 at SNOLAB
Backgroundsuppression better than2.6 E-8 demonstratedto date
For DEAP/CLEAN 3600suppression of > 10-9
is required.
Note also that sources of Ar depleted x 20 in 39Ar have been found and are being developed with the Princeton group.
CDMS-II: ~50 kg-days (Ge)XENON-10: ~300 kg-days (Xe)DEAP- 3600: 1,000,000 kg-days (Ar) (3 yrs)
SuperCDMS25 kg
PICASSO
Project In CAnada to Search for Supersymmetric Objects
• detectors consist of tiny (5 to 100 m) halocarbon superheated-liquid droplets (e.g. C3F8, C4F10) embedded in a gel
• WIMP-induced nuclear recoils nucleate a bubble; expanding, evaporating bubble produces an acoustic signal detected by piezo microphone
insensitive to beta and gamma radiation; some discrimination exists for alphas
19F favourable target to search for “spin-dependent” WIMP scattering
32 detector modulescontaining 4 L of gel
Phase 1a: (published in ’05 PLB, NIM) 20g 2kgd
Phase Ib: (ongoing)2.6 kg 700 kgdBckg red. 1/6 – 1/10 Phase Ib/100:2.6 kg 700 kgdBckg: red. 1/100 Phase II:25 kg 7000 kgdLarger modules 30L
PICASSO PHASES
MSSMTheoryPredictions
SPIN DEPENDENT WIMP INTERACTION: Studied with Fluorine dispersed in supersaturated gel – WIMP nuclear recoils create bubbles - detected acoustically.Low response for other radioactivity. Breakthrough this year: alpha discrimination
H eliumA ndL eadO bservatory
A lead detector forsupernova neutrinosin SNOLAB
Laurentian, TRIUMF, SNOLAB, LANL, Washington, Duke, Minnesota, Digipen IT HALO-1: 80 tons of existing Pb
& SNO Neutron Detector Array
Pb: Most sensitivity to electron neutrinos.~ 50 events for SN at center of Galaxy.
SUMMARY
• SNO operation is complete, further papers to come over next year.
• SNOLAB construction is complete, final cleanliness in progress.
• Several experiments are already running in existing clean space.
• A number of other experiments have been approved for siting in the near future for neutrinos, double beta decay, Dark Matter.
• Stay tuned for some exciting future physics results.