Energy Recovery Linac (ERL): Properties and Prospects

Transcription

1 Energy Recovery Linac (ERL): Properties 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,

2 Growth in Synchrotron Radiation Science INSPEC: Synchrotron Radiation (not astronomy) Protein Data Bank: Deposits / year Number of Publications Number of PDB Deposits Shen July 23,

3 Not Every Scientific Discipline INSPEC: Cold Fusion Number of Publications Shen July 23,

4 New Synchrotron Sources Question: Are there alternatives to storage-ring ring based 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: 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,

5 Storage Ring Sources Mature and well-understood Equilibrium of stored beam in entire ring Each electron bunch ~ 10,000 turns to reach equilibrium Emission of synchrotron radiation Perturbations on electron trajectories Limits on energy spread, horizontal emittance, bunch length Shen July 23,

6 Single 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,

7 Energy Recovery Linac Injector: high-brilliance electron bunches generated by fs laser on photocathode are accelerated to ~10MeV M. Tigner, Nuovo Cimento 37, 1228 (1965) Main Linac: superconducting cells accelerate electron bunches to 5-7 GeV, and recover energy from returning bunches (180 o 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 m Shen July 23,

8 ERL Concept Works! 48 MeV 5 ma Average IR Power 1720 W Average current 5 ma Electron energy 48 MeV Wavelength range µm Charge per pulse >60 pc Pulse length ps Repetition frequency up to MHz Energy recovery efficiency 99.97% Shen July 23,

9 Basic Comparison on Machine Issues ERL and XFEL ERL XFEL 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 m Shen July 23,

10 Basic Comparison on Machine Issues ERL and Storage Rings Storage Ring stored-beam + undulator low bunch charge multi pass energy stored high rep-rate simultaneous beamlines ERL linac driven undulator low bunch charge single pass energy recycled high rep-rate simultaneous beamlines ESRF m Shen July 23,

11 Activities at Cornell on ERL February 11, 2000 ERL proposed, by Tigner to advisory board June-July 2000 White Paper on ERL, by Gruner, Bilderback, Tigner August 11-12, 2000 Machine physics workshop on ERL December 2-3, 2000 X-ray science workshop on ERL July 6, 2001 Proposal of ERL Phase-I, submitted to NSF August 21, 2001 Workshop on ERL at SRI 2001, organized by Bilderback & Gruner (), Kao (BNL) and Williams (TJNAF) ERL website: Shen July 23,

12 Preliminary Design Parameters of ERL ERL high-flux ERL high-coherence Machine design Insertion device Energy E G (GeV) Current I (ma) Charge q (nc/bunch) ε x (nm-rad) ε y (nm-rad) Bunch fwhm τ (ps) # of bunches f (Hz) Undulator L (m) Period λ u (cm) # of period N u Horizontal β x (m) Vertical β y (m) Undulator E st harmonic E 1 (kev) Shen July 23,

13 ERL: Expected Performance Average Brilliance (ph/s/0.1%/mm 2 /mr 2 ) LCLS SASE Sp8 25m APS 4.8m APS 2.4m LCLS spont. ERL 25m 0.015nm 10mA Sp8 5m ESRF U35 24p wiggler 0.15nm 100mA 49p wiggler Peak Brilliance (ph/s/0.1%/mm 2 /mr 2 ) nm 100mA 4.7ps Sp8 25m ESRF U35 49-pole G/A-wiggler τ=153ps, f=17.6mhz (9x5) 24-pole F-wiggler ERL 25m 0.015nm 10mA 0.3ps Sp8 5m APS 2.4m 0.15nm 100mA 0.3ps Photon Energy (kev) Photon Energy (kev) Shen July 23,

14 ERL: Expected Performance Coherent Fraction 10 0 LCLS SASE APS 4.8m ESRF U35 ERL 25m 0.015nm 10mA ERL 25m 0.15nm 100mA APS 2.4m 25m Sp8 5m Peak Photon Degeneracy Parameter nm 100mA APS 4.8m ESRF U35 Sp8 25m Sp8 5m ERL 25m 0.015nm 10mA APS 2.4m Photon Energy (kev) Photon Energy (kev) Shen July 23,

15 ERL: Source Size and Pulse Length ESRF ma ε x = 4 nm mrad ε y = 0.01 nm mrad B = ph/s/mm 2 /mrad 2 /0.1%BW L ID = 5 m ERL / 10 ma ε x = ε y = 0.2 / 0.02 nm mrad B = ph/s/mm 2 /mrad 2 /0.1%BW B = ph/s/mm 2 /mrad 2 /0.1%BW L ID = 25 m ERL (w/ compression) ERL (no compression) ESRF t Shen July 23,

16 Power / Heat Loads ERL 5.3GeV SPring-8 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 20m 2600 W/mm W/mm W/mm W/mm 2 Peak power 86.9 MW 8.7 MW 2.5 MW 1.3 MW 15 GeV 25 GeV ID length 100 m 87 m Beam current µa 63 µa Total ave. power 3 W 1.6 kw 20m 63 W/mm kw/mm 2 Peak power 9 GW 60 GW Shen July 23,

17 ERL Beam Lines ERL beam lines are similar to 3rd SR such as Spring-8 TESLA Shen July 23,

18 Basic Properties of ERL Low e-beam emittance Small round beams Short sub-ps x-ray pulses Beamlines similar to 3rd SR High repetition rate Flexible operation ERL allows: Exploration of new sciences that are not possible at existing sources Accommodation of existing experiments with substantial improvements Shen July 23,

19 X-ray Science Workshop with ERL Cornell University, Ithaca, New York December 2-3, 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 Mellon 12. 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 Arthur 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,

20 X-ray Science at ERL All brilliance-driven experiments that require a large number of photons per phase-space volume: x, θ x, y, θ y, t, E Improved: : more photons Expanded: : more phase-space space parameters New: : parameters in new territory Shen July 23,

21 X-ray Science at ERL: Improved Micro-beam / µ-probe: x Larson (2000) Bilderback (2000), ERL Workshop Shen July 23,

22 X-ray Science at ERL: Improved Time-resolved x-ray x studies: t Larson (2000) ERL Workshop Shen July 23,

23 X-ray Science at ERL: Improved photon-correlation spectroscopy: θ x, t Dierker (2000), ERL Workshop Shen July 23,

24 X-ray Science at ERL: Improved Inelastic x-ray x scattering: E S.H. Chen (2000) ERL Workshop Data from ESRF with 650 µev resolution E. Alp (2000) ERL Workshop Shen July 23,

25 X-ray Science at ERL: Expanded Expanded capabilities: => additional phase space variables high-q photon-correlation spectroscopy: θ x, t, E t = 2.5ns (now, DeJeu) => 0.77ns with ERL Sutton et al. (1995) >>> Fe 3 Al (1/2,1/2,1/2) high-resolution coherent diffraction: x, θ, E Noncrystalline structures Miao et al. (1999) >>> reconstruction to 80 nm Shen July 23,

26 X-ray Science at ERL: Expanded high-pressure inelastic scattering: x, E Parise, Mao, Hemley (2000) ERL Workshop Shen July 23,

27 X-ray Science at ERL: New parameters in new regimes Peak 8 kev (ph/s/0.1%/mm 2 /mr 2 ) rd SR APS upg 49p 24p Sp8-25m 2nd SR ESRF APS ERL 0.015nm 0.01A 0.15nm 0.1A 0.15nm 0.1A 4.7ps 1.5nm 0.1A ALS fs BLs ALS sect.6 undulator ALS Ultra-fast pump-probe probe studies: σ τ = 100 fs, f = MHz GHz Techert, Schott, Wulff, PRL 86, 2030 (2001). Time resolved XRD at ESRF, resolution 10 ps X-ray Pulse Duration τ (ps) Shen July 23,

28 X-ray Science at ERL: New parameters in new regimes Peak Coherent Electric Field (V/m) strong-field regime perturbative nonlinear regime linear regime CO 2 Gas lasers Nd: Glass Ruby Terawatt Ti: Al 2 O 3 electron binding field in atoms Excimers Higher Harmonics Generation Tunable dye lasers TESLA XFEL LCLS XFEL atmospheric E-field at earth surface ERL 0.015nm 0.15nm ESRF APS ALS Sp-8 wigglers Nonlinear condensed matter: coherent E-field E > 10 7 V/m degeneracy parameter ~ photon absorption? Photon Energy (ev) Shen July 23,

29 X-ray Science at ERL: New more ideas... Round x-ray x beams: Flexible pulse train, quasi-cw: Vertical polarization? Random pulse sequence? Jens Als-Nielson Don Bilderback Horizontal diffractometers? High frequency response? Jens Als-Nielson Ken Finkelstein Shen July 23,

30 Proposed Timeline at Cornell ERL ERL Phase-I FY02 Phase-I proposal (July 01) Phase-I ERL 100MeV 100mA FY06 Phase-II ERL ERL Phase-II 2010 Phase-II ERL operation Shen July 23,

31 Phase-I I ERL Beam Energy Injection Energy Beam current 100 MeV 5 MeV 100 ma Charge per bunch 77 pc Rms Emittance, norm. 2 µm Shortest bunch length 100 fs Perspective view of the injector TTF 9-cell 1.3 GHz niobium cavity (courtesy of DESY) (Q 0 ~ MV/m) Systems, Inc. Energy Advanced Shen July 23,

32 Phase-I I ERL Challenges to be resolved! Low emittance production & preservation emittance compensation in the Injector 4 / 3 N e ρ coherent synchrotron radiation ( k ~ 4 ), wakes γ σ L! 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 Q L possible (microphonics)! Diagnostics Shen July 23,

33 Phase-II ERL Parameter Value Unit Beam Energy 5-7 GeV Average Current 100 / 10 ma Fundamental frequency 1.3 GHz Charge per bunch 77 / 8 pc Injection Energy 10 MeV Normalized emittance 2 / 0.2* µm Energy spread % Bunch length in IDs 0.1-2* ps Total radiated power 400 kw Shen July 23,

34 Phase-II ERL Optics Challenges Κ high-heat-load capable Κ 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,

35 Conclusions Energy Recovery Linac (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: Shen July 23,

36 Source Emittance and Brilliance Phase-space space Emittance: EM wave: E(r, t) = E 0 e i(k r ωt) x x Integrated total flux F n x ε x = σ x σ x σ x y ε y = σ y σ y σ y σ E E ε τ = σ τ σ E / E σ x x σ y y σ τ t Brilliance: : photon flux density in phase-space space Average B = F n (2π) 2 ε x ε y Peak B ^ = F n (2π) 3 ε x ε y ε τ Shen July 23,

37 X-ray Science at ERL: Expanded time-resolved µ-beam studies: x, E Parise, Mao, Hemley (2000) ERL Workshop Shen July 23,