energy recovery linac (erl): properties and...

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


CHESS

Growth in Growth in Synchrotron Radiation ScienceSynchrotron Radiation Science

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INSPEC: Synchrotron Radiation

(not astronomy)

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CHESSNot Every Scientific Discipline …...Not Every Scientific Discipline …...

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INSPEC: Cold Fusion


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


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


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


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


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%


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

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1010

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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

energy recovery linac (erl): properties and...

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