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Shen July 23, 2001 1
CHESS
Energy Recovery Energy Recovery Linac Linac (ERL):(ERL):Properties and ProspectsProperties and Prospects
Q. Shen, D. Bilderback, K. Finkelstein, E. Fontes, S. Gruner,R. Headrick, A. Kazimirov, D. Smilgies, C.-S. Zha
Cornell High Energy Synchrotron Source, Cornell University
I. Bazarov, H. Padamsee, R. Talman, M. Tigner, Laboratory for Nuclear Studies, Cornell University
G. Krafft, L. Merminga, C. Sinclair, Thomas Jefferson National Accelerator Facility
⇒ Introduction to ERL concept
⇒ Preliminary design parameters
⇒ Science potentials of ERL
⇒ Comparisons with present SR and XFEL
⇒ Future plan and prospects
Shen July 23, 2001 2
CHESS
Growth in Growth in Synchrotron Radiation ScienceSynchrotron Radiation Science
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INSPEC: Synchrotron Radiation
(not astronomy)
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Protein Data Bank:Deposits / year
Shen July 23, 2001 3
CHESSNot Every Scientific Discipline …...Not Every Scientific Discipline …...
1975
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0
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f Pub
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INSPEC: Cold Fusion
Shen July 23, 2001 4
CHESSNew Synchrotron SourcesNew Synchrotron Sources
⇒ Question:Question: Are there alternatives to storageAre there alternatives to storage--ring based sources ?ring based sources ?
⇒ Proposed new sources:Proposed new sources:
• Ultimate storage ring light source: USRLS• X-ray free electron lasers (XFEL): LCLS, TESLA• Energy recovery linac (ERL): Cornell, BNL, ALS, ...
⇒ From users’ perspective:From users’ perspective:
• High intensity & brilliance• Beam is there all the time, without decay in current• High degree of 2D transverse coherence• Ultra-short x-ray pulses• Flexible source operation to meet specific needs
Shen July 23, 2001 5
CHESSStorage Ring SourcesStorage Ring Sources
• Equilibrium of stored beam in entire ring• Each electron bunch ~ 10,000 turns to reach equilibrium • Emission of synchrotron radiation
• Mature and well-understood
• Perturbations on electron trajectories• Limits on energy spread, horizontal emittance, bunch length
Shen July 23, 2001 6
CHESSSingle Pass DeviceSingle Pass Device
• Single-pass non-equilibrium device• Low emittance and short pulses from injector can be preserved • Ultra-small round beam • Potential for ultra-high brilliance • Electron bunches dumped after single pass • Difficult to maintain high current • Enormous power bill• Not economical or practical
Shen July 23, 2001 7
CHESSEnergy Recovery Energy Recovery LinacLinac
M. Tigner, Nuovo Cimento 37, 1228 (1965) Injector: high-brilliance electron bunches generated by fs laser on photocathode are accelerated to ~10MeV
350 - 500 m
Main Linac: superconducting cells accelerate electron bunches to 5-7 GeV, and recover energy from returning bunches (180o out of phase)
Transport loop: produces high-brilliance x-ray beams through undulators, and reinjects electrons into main linac for energy recovery
Accelerating bunch Returning bunch
Shen July 23, 2001 8
CHESSERL Concept Works !ERL Concept Works !
48 MeV 5 mA
Average IR Power 1720 WAverage current 5 mAElectron energy 48 MeV Wavelength range 3-6.2 µm Charge per pulse >60 pCPulse length 0.4-1.7 psRepetition frequency up to 74.85 MHzEnergy recovery efficiency 99.97%
Shen July 23, 2001 9
CHESS
Basic Comparison on Machine IssuesBasic Comparison on Machine IssuesERL and XFELERL and XFEL
ERLERL XFELXFEL• linac driven undulator • linac driven long undulator• low bunch charge single pass • high bunch charge single pass• energy recycled • self-amplified spont. emission• high rep-rate • low rep-rate• simultaneous beamlines • multiplexed beamlines
350 - 500 m
Shen July 23, 2001 10
CHESS
Basic Comparison on Machine Issues Basic Comparison on Machine Issues ERL and Storage RingsERL and Storage Rings
Storage RingStorage Ring ERLERL• stored-beam + undulator • linac driven undulator
• low bunch charge single pass• low bunch charge multi pass• energy recycled• energy stored• high rep-rate• high rep-rate• simultaneous beamlines• simultaneous beamlines
350 - 500 mESRF
Shen July 23, 2001 11
CHESS
Activities at Cornell on ERLActivities at Cornell on ERL20002000--20012001
February 11, 2000 ERL proposed, by Tigner to CHESS advisory boardJune-July 2000 White Paper on ERL, by Gruner, Bilderback, Tigner
August 11-12, 2000 Machine physics workshop on ERLDecember 2-3, 2000 X-ray science workshop on ERL
July 6, 2001 Proposal of ERL Phase-I, submitted to NSFAugust 21, 2001 Workshop on ERL at SRI 2001, organized by
Bilderback & Gruner (CHESS), Kao (BNL) and Williams (TJNAF)
ERL website: http://erl.chess.cornell.edu/
Shen July 23, 2001 12
CHESS
PreliminaryPreliminaryDesign Parameters of ERLDesign Parameters of ERL
ERLhigh-flux
ERLhigh-coherence
Energy EG (GeV) 5.3 5.3
Current I (mA) 100 10
Charge q (nC/bunch) 0.077 0.008
εx (nm-rad) 0.15 0.015
εy (nm-rad) 0.15 0.015
Bunch fwhm τ (ps) 0.3 − 5 0.3 − 5
Mac
hine
des
ign
# of bunches f (Hz) 1.3·109 1.3·109
Undulator L (m) 25 25
Period λu (cm) 1.7 1.7
# of period Nu 1470 1470
Horizontal βx (m) 12.5 4.0
Vertical βy (m) 12.5 4.0
Undulator K @ E1 1.38 1.38
Inse
rtion
dev
ice
1st harmonic E1 (keV) 8.0 8.0
Shen July 23, 2001 13
CHESSERL: Expected PerformanceERL: Expected Performance
10 100
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
ESRF U35Sp8 5m
Sp8 25m
APS 4.8m
APS 2.4m
0.15nm 100mA
ERL 25m 0.015nm 10mA
LCLS SASE
LCLS spont.
CHESS 24p wiggler
CHESS 49p wiggler
Aver
age
Brilli
ance
(ph/
s/0.
1%/m
m2 /m
r2 )
Photon Energy (keV)10 100
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
0.15nm100mA 0.3ps
CHESS 49-pole G/A-wigglerτ=153ps, f=17.6MHz (9x5)
CHESS 24-pole F-wiggler
Sp8 25m
Sp8 5m
ESRF U35APS 2.4m
0.15nm 100mA 4.7ps
ERL 25m 0.015nm 10mA 0.3ps
Peak
Bril
lianc
e (p
h/s/
0.1%
/mm
2 /mr2 )
Photon Energy (keV)
Shen July 23, 2001 14
CHESSERL: Expected PerformanceERL: Expected Performance
3 4 5 6 7 8 910 20 30 40 5010-5
10-4
10-3
10-2
10-1
100 LCLS SASE
APS 2.4m
ESRF U35
APS 4.8m
Sp8 5m25m
ERL 25m0.15nm 100mA
ERL 25m0.015nm 10mA
Coh
eren
t Fra
ctio
n
Photon Energy (keV)
3 4 5 6 7 8 910 20 30 40 50
10-4
10-3
10-2
10-1
100
101
102
103
Sp8 5m
Sp8 25mESRF U35
APS 2.4m
APS 4.8m
0.15nm100mA
ERL 25m0.015nm 10mA
Peak
Pho
ton
Deg
ener
acy
Para
met
er
Photon Energy (keV)
Shen July 23, 2001 15
CHESS
ERL: Source Size and Pulse LengthERL: Source Size and Pulse Length
ERL 5 GeV @ 100 / 10 mAεx = εy = 0.2 / 0.02 nm mradB = 1022 ph/s/mm2/mrad2/0.1%BWB = 3 ×1022 ph/s/mm2/mrad2/0.1%BWLID = 25 m
ESRF 6 GeV @ 200 mAεx = 4 nm mradεy = 0.01 nm mradB = 5×1020 ph/s/mm2/mrad2/0.1%BWLID = 5 m
ESRFERL (no compression)
ERL (w/ compression)
t
Shen July 23, 2001 16
CHESSPower / Heat LoadsPower / Heat Loads
ERL undulator @ 5.3GeV SPring-8 undulator @ 8 GeV
ID length 25 m 25 m 25 m 4.5 m
Beam current 100 mA 10 mA 100 mA 100 mA
Total ave. power 33.9 kW 3.4 kW 31.2 kW 15.7 kW
Power/Area @ 20m 2600 W/mm2 260 W/mm2 4568 W/mm2 1830 W/mm2
Peak power 86.9 MW 8.7 MW 2.5 MW 1.3 MW
LCLS @ 15 GeV TESLA @ 25 GeV
ID length 100 m 87 m
Beam current 0.072 µA 63 µA
Total ave. power 3 W 1.6 kW
Power/Area @ 20m 63 W/mm2 200 kW/mm2
Peak power 9 GW 60 GW
Shen July 23, 2001 17
CHESSERL Beam LinesERL Beam Lines
ERL beam lines are similarto 3rd SR such as Spring-8
TESLA
Shen July 23, 2001 18
CHESSBasic Properties of ERLBasic Properties of ERL
• Low e-beam emittance • Beamlines similar to 3rd SR• Small round beams • High repetition rate• Short sub-ps x-ray pulses • Flexible operation
⇒ Exploration of new sciences that are not possible at existing sources
⇒ Accommodation of existing experiments withsubstantial improvements
ERL allows:
Shen July 23, 2001 19
CHESS
XX--ray Science Workshop with ERLray Science Workshop with ERLCornell University, Ithaca, New YorkCornell University, Ithaca, New York
December 2December 2--3, 20003, 2000
1. ERL Overview: Sol Gruner, Cornell Univ. 2. ERL Machine Opportunities: Maury Tigner, Cornell U. 3. ERL X-ray Opportunities: Don Bilderback, Cornell U. 4. ERL Insertion Device Design Considerations: Pascal Elleaume, ESRF 5. Coherent X-ray Microscopy: Chris Jacobson & Janos Kirz, U. Copenhagen 6. Sources of Coherent X-rays: synchrotorns, ERLs, EFELs: John Arthur, SSRL 7. Collective Dynamics by High Resolution Inelastic X-ray Scattering Spectroscopy: Sow-Hsin Chen, MIT 8. X-ray Photon Correlation Spectroscopy: Steve Dierker, U. Michigan 9. Localized Vibrational and Spin Wave Modes in Nonlinear Periodic Lattices: Al Sievers, Cornell U.
10. Condensed Matter Research at high Pressure: Beyond 3rd Generation Facilities: John Parise, SUNY Stony Brook 11. Probing Polycrystals with Microfocused High-Energy X-rays: Bob Suter, Carnegie Mellon12. Structural and Electronic Studies in the Time Domain: Phil Heimann, ALS 13. Atomic-to-macro Structure and Evolution with Shorter Pulses and Higher Brilliance X-ray Beams: Ben Larson, ORNL 14. Frontiers of X-ray Microdiffraction: Gene Ice, ORNL 15. Microfluorescence, Microspectroscopy and Microtomography Application: Mark Rivers, U. Chicago 16. ERL Opportunities Employing Crystal Optics: Al Macrander, APS 17. Intensity Fluctuation Spectroscopy using Coherent X-rays: Mark Sutton, McGill, Joel Brock, Cornell U. 18. How an ERL Might Benefit Our Understanding of Elementary Excitations in Condensed Matter: Ercan Alp, APS 19. Monitor Ion Beam and Ion-Solid Structure Monitoring: Richard Matyi, NIST 20. Exploring Some Frontiers of ERL Machine: Ivan Bazarov, Cornell U. 21. Vertically Polarized Undulators: Jens Als-Nielson, U. Copenhagen 22. ERL machine for NSLS: Peter Siddons, BNL 23. Go to Double Undulator for 2X brilliance: John Galayda, ANL 24. Comparison of Storage Rings, ERL, & XFEL x-ray sources: Gopal Shenoy & John Arthur25. 10 nm diameter x-ray beams with glass capillary: Don Bilderback, Cornell U. 26. ERL Timing & CEBAF Overview: Geoff Kraft, Jefferson National Laboratory 27. Summary of ERL Beamline Needs
Shen July 23, 2001 20
CHESSXX--ray Science at ERLray Science at ERL
All brilliance-driven experiments that require a large number of photons per phase-space volume:
∆x, ∆θx, ∆y, ∆θy, ∆t, ∆E
⇒ ImprovedImproved: more photons: more photons
⇒ ExpandedExpanded: more phase: more phase--space parameters space parameters
⇒ NewNew: parameters in new territory: parameters in new territory
Shen July 23, 2001 21
CHESS
XX--ray Science at ERL: ray Science at ERL: ImprovedImproved•• MicroMicro--beam / beam / µµ--probe: probe: ∆∆xx
Larson (2000)
Bilderback (2000), ERL Workshop
Shen July 23, 2001 22
CHESS
XX--ray Science at ERL: ray Science at ERL: ImprovedImproved•• TimeTime--resolved xresolved x--ray studies: ray studies: ∆∆tt
Larson (2000)ERL Workshop
Shen July 23, 2001 23
CHESS
XX--ray Science at ERL: ray Science at ERL: ImprovedImproved•• photonphoton--correlation spectroscopy:correlation spectroscopy: ∆θ ∆∆θ ∆xx, , ∆∆tt
Dierker (2000), ERL Workshop
Shen July 23, 2001 24
CHESS
XX--ray Science at ERL: ray Science at ERL: ImprovedImproved•• Inelastic xInelastic x--ray scattering: ray scattering: ∆∆EE
S.H. Chen (2000)ERL Workshop
Data from ESRF with 650 µeV resolution
E. Alp (2000)ERL Workshop
Shen July 23, 2001 25
CHESSXX--ray Science at ERL: ray Science at ERL: ExpandedExpanded
⇒ Expanded capabilitiesExpanded capabilities: : =>=> additional phase space variablesadditional phase space variables
•• highhigh--qq photonphoton--correlation correlation spectroscopy: spectroscopy: ∆θ ∆∆θ ∆xx, , ∆∆tt, , ∆∆EE
Sutton et al. (1995) >>>Fe3Al (1/2,1/2,1/2)
∆t = 2.5ns (now, DeJeu)=> 0.77ns with ERL
•• highhigh--resolution coherent resolution coherent diffraction: diffraction: ∆∆xx,, ∆θ∆θ, , ∆∆E E
⇒Noncrystallinestructures
Miao et al. (1999) >>>reconstruction to 80 nm
Shen July 23, 2001 26
CHESS
XX--ray Science at ERL: ray Science at ERL: ExpandedExpanded•• highhigh--pressure inelastic scattering: pressure inelastic scattering: ∆∆xx, , ∆∆EE
Parise, Mao, Hemley (2000)ERL Workshop
Shen July 23, 2001 27
CHESS
XX--ray Science at ERL: ray Science at ERL: NewNew⇒⇒ parameters in new regimesparameters in new regimes
•• UltraUltra--fast pumpfast pump--probe studies: probe studies: σσττ == 100100 fsfs,, ff = = MHz MHz −− GHzGHz
1000 100 10 1 0.1
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
ALS sect.6undulator
ALS 5.3.1
CHESS 49p
24p
0.15nm 0.1A4.7ps
0.015nm 0.01A
0.15nm 0.1A
1.5nm 0.1AAPS upgSp8-25m
ESRFAPS
ALS fs BLs2nd SR
3rd SR
ERL
Peak
Bril
lianc
e @
8 k
eV (p
h/s/
0.1%
/mm
2 /mr2 )
X-ray Pulse Duration τ (ps)
Techert, Schott, Wulff, PRL 86, 2030 (2001).
Time resolved XRD at ESRF,resolution 10 ps
Shen July 23, 2001 28
CHESS
XX--ray Science at ERL: ray Science at ERL: NewNew
•• Nonlinear condensed matter: Nonlinear condensed matter: coherent Ecoherent E--field > 10field > 1077 V/mV/mdegeneracy parameter ~10degeneracy parameter ~1022
10-2 10-1 100 101 102 103 104 105101
102
103
104
105
106
107
108
109
1010
1011
1012
Gaslasers
atmospheric E-fieldat earth surface
stro
ng-fi
eld
regi
me
line
ar re
gim
e pe
rturb
ativ
e n
onlin
ear r
egim
e
electron binding field in atoms
CO
2
Nd:
Gla
ss R
uby
Excimers
CHESS wigglers
Sp-8ESRF
APSALS
0.15nm
ERL0.015nm
Higher HarmonicsGeneration
Tunabledye lasers
TerawattTi: Al2O3 LCLS XFEL
TESLA XFEL
Peak
Coh
eren
t Ele
ctric
Fie
ld (V
/m)
Photon Energy (eV)
⇒⇒ parameters in new regimesparameters in new regimes
2-photonabsorption?
Shen July 23, 2001 29
CHESS
XX--ray Science at ERL: ray Science at ERL: NewNew⇒⇒ more ideas …...more ideas …...
•• Round xRound x--ray beams: ray beams: •• Flexible pulse train, quasiFlexible pulse train, quasi--CW: CW:
Vertical polarization?
Jens Als-Nielson
Random pulsesequence?
Don Bilderback
Horizontaldiffractometers?
Jens Als-Nielson
High frequencyresponse?
Ken Finkelstein
Shen July 23, 2001 30
CHESSProposed Timeline at CornellProposed Timeline at Cornell
ERL Phase-I
ERL Phase-II
100MeV 100mA
ERLPhase-Iproposal(July ‘01)
FY02Phase-I ERL
FY06Phase-II ERL
Phase-II ERLoperation2010
Shen July 23, 2001 31
CHESSPhasePhase--I ERLI ERL
Beam Energy 100 MeVInjection Energy 5 MeVBeam current 100 mA
Charge per bunch 77 pCRms Emittance, norm. 2 µmShortest bunch length 100 fs
TTF 9-cell 1.3 GHz niobium cavity(courtesy of DESY)
(Q0 ~ 1010 @ 20 MV/m)
Perspective view of the injector
AdvancedEnergy
Systems, Inc.
Shen July 23, 2001 32
CHESSPhasePhase--I ERLI ERL
Challenges to be resolvedChallenges to be resolved
! Low emittance production & preservation• emittance compensation in the Injector• coherent synchrotron radiation ( ), wakes
! Photocathode longevity at high average current (vacuum)! Longitudinal phase space preservation in bunching (curvature
correction)! Beam break up in the main linac (higher-order modes damping)! Beam loss ~ µA (halo)! Highest QL possible (microphonics)! Diagnostics …
3/ 4
4 ~
L
e N k σ
ρ
γ
Shen July 23, 2001 33
CHESSPhasePhase--II ERLII ERL
Parameter Value UnitBeam Energy 5-7 GeVAverage Current 100 / 10 mAFundamental frequency 1.3 GHz
Charge per bunch 77 / 8 pC
Injection Energy 10 MeVNormalized emittance 2 / 0.2* µmEnergy spread 0.02-0.3 %
Bunch length in IDs 0.1-2* psTotal radiated power 400 kW
Shen July 23, 2001 34
CHESS
PhasePhase--II ERLII ERLOptics ChallengesOptics Challenges
Κ high-heat-load capableΚ brilliance preserving to provide high transverse coherence Κ optics to manipulate, preserve and produce short pulses
Freund (2001), used by Hastings & Tschentscher, in TESLA Technical Design Report, ed. Materlik & Tschentscher (DESY, Hamburg)
Shen July 23, 2001 35
CHESSConclusionsConclusions
Energy Recovery Energy Recovery Linac Linac (ERL) would offer:(ERL) would offer:
⇒ an exciting alternative to storage-ring & XFEL sources
⇒ x-ray beam quality superior to storage-rings
⇒ improved, expanded, and new science applications
⇒ accommodation of both new and existing expts.
⇒ similarities in beamline design and cost-effectiveness
⇒ ERL would be complementary to XFELs
⇒ possibility of upgrading all storage-rings
ERL website: http://erl.chess.cornell.edu/
Shen July 23, 2001 36
CHESSSourceSource EmittanceEmittance and Brillianceand Brilliance
xx’
Integrated total flux Fn
⇒ PhasePhase--space space EmittanceEmittance::
EM wave: E(r, t) = E0 ei(k·r−ωt)
t
E
στ
σE
ετ = στ σE / E
y
y’
σy
σy’
εy = σy σy’
x
x’
σx
σx’
εx = σx σx’
⇒ BrillianceBrilliance: photon flux density in phase: photon flux density in phase--spacespace
B =Fn
(2π)3 εx ·εy·ετ
^PeakB =Fn
(2π)2 εx ·εyAverage
Shen July 23, 2001 37
CHESS
XX--ray Science at ERL: ray Science at ERL: ExpandedExpanded•• timetime--resolved resolved µµ--beam studies: beam studies: ∆∆xx, , ∆∆EE
Parise, Mao, Hemley (2000)ERL Workshop
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