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CLIC e + sources status

CLIC e + sources status. L. Rinolfi with contributions from F. Antoniou, H. Braun, A. Latina, Y. Papaphilippou, F. Zimmermann / CERN R. Chehab / IPNL/IN2P3 - Lyon, V.M.Strakhovenko / BINP - Novosibirsk A. Variola, A. Vivoli / LAL - Orsay, A. Ferrari / Uppsala University

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CLIC e + sources status

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  1. CLIC e+ sources status L. Rinolfi with contributions from F. Antoniou, H. Braun, A. Latina, Y. Papaphilippou, F. Zimmermann / CERN R. Chehab / IPNL/IN2P3 - Lyon, V.M.Strakhovenko / BINP - Novosibirsk A. Variola, A. Vivoli / LAL - Orsay, A. Ferrari / Uppsala University E. Buylak, P. Gladkikh / NCS / KIPT - Kharkov W. Gai, W. Liu / ANL, J. Sheppard / SLAC T. Kamitani, T. Omori / KEK, M. Kuriki / Hiroshima University

  2. The CLIC Injector complex in 2008  30 m  30 m e- Main Linac e+ Main Linac e- BC2 e+ BC2 12 GHz 12 GHz 12 GHz, 100 MV/m, 21 km 12 GHz, 100 MV/m, 21 km 9 GeV 48 km 3 TeV Base line configuration Booster Linac 6.6 GeV 4 GHz 473 m e+ BC1 e- BC1 4 GHz 2.424 GeV 365 m 4 GHz 2.424 GeV 365 m e+ DR e- DR e- PDR e+ PDR 2.424 GeV 2.424 GeV 365 m 365 m Injector Linac 2.2 GeV 2 GHz 228 m e-/g Target g/e+ Target Primary beam Linac for e- 5 GeV Laser Pre-injector Linac for e+ 200 MeV Pre-injector Linac for e- 200 MeV DC gun Polarized e- 2 GHz 2 GHz e- gun AMD 2 GHz

  3. Main beam parameters comparison At the entrance of the Main Linac for e- and e+

  4. CLIC parameters relevant for e+ source Assuming ~ 90 % efficiency between the PDR and the Main Linac Total pulse length 156 ns Assuming ~ 70 % capture efficiency in the PDR Repetition frequency 50 Hz Assuming ~ 95 % efficiency between the Pre-Injector and the Injector Linac

  5. Conventional e+ source based on channelling Yield: 0.9 e+ / e- @ 200 MeV e- e- g e+ • Charged particles are swept off after the crystal:only g (> 2MeV) impinge on the amorphous target. • The distance between the 2 targets is 2 meters. e+ A e- beam impinges on the crystal: - energy of 5 GeV - beam size of 2.5 mm • A crystal e+ source : • - a 1.4 mm thick W crystal • oriented along <111> axis • - a 10 mm thick W amorphous disk e- crystal amorphous R. Chehab, V. Strakovenko, A. Variola, A. Vivoli / LAL

  6. CLIC Channeling e+ source Yield (at 200 MeV): 0.9 e+ / e- Experimental limit found at SLAC: PEDD = 35 J/g

  7. Beam parameters with channeling Positrons after capture section at 270 MeV Q ~ 1 nC See R. Chehab talk at this workshop

  8. Beam parameters comparison Positrons after capture section at the end of the pre-injector linac Accelerating gradient MV/m 15 18

  9. Longitudinal phase space at 2.4 GeV Energy spread = 65 MeV Dp/p (rms) = 2.7 % If PDR acceptance is Dp/p = ± 1 % = >82 % capture efficiency e+

  10. Required CLIC Pre-Damping Ring > ± 1% as small as possible

  11. CLIC base line configuration for e+ source e-/g Target g/e+ Target Pre-injector Linac for e+ 200 MeV Primary beam Linac for e- 5 GeV Thermionic gun AMD 2 GHz The channeling process allows a good e+ yield and one of the main advantage is the reduction of the beam energy deposition in the targets. For the base line configuration, based on channeling process, a solution exists with a single target station providing unpolarized e+ to fulfill the CLIC parameters.

  12. CLIC polarized e+ source • Undulator • Laser Compton • Drive Beam Linac => no laser stacking cavity & no stacking in the PDR • Storage Ring => laser stacking cavity + stacking in the PDR • ERL => laser stacking cavity + stacking in the PDR

  13. CLIC 2007 based on undulator scheme To the IP e- beam Cleaning chicane Ti alloy e+ e+ 250 GeV 2.2 GeV NC Linac 450 m Injector Linac G = 17 MV/m E = 2.424 GeV f RF = 1.5 GHz f rep= 50 Hz Pre-Injector Linac G = 20 MV/m E = 200 MeV fRF = 1.5 GHz B = 0.5 T Undulator K = 0.75 lu = 1.5 cm L = 100 m

  14. Optimizing for yield • Drive e- beam energy: 250GeV • Undulator K: 0.75 • Undulator period: 1.5cm • Length of undulator: 100m • Drift to target: 450m • Accelerator gradient and focusing: 50MV/m for beam energy <250MeV, 0.5T background solenoid field focusing; for 250MeV to 2.4GeV, 25MV/m with discrete FODO set. • OMD: Non immersed, ramping distance 2cm • 1)7T-0.5T and 5T-0.5T, the thickness varies from 15cm to 80cm in 5cm steps; • 2) the thickness fixed at 20cm, B0-0.5T, B0 varies from 1 T to 10T • Photon collimator: None • Target material: 0.4 rl Titanium, non-immersed • Yield is calculated as Ne+ captured/Ne- in drive beam. • Positron capture is calculated by numerical cut using damping ring acceptance window: +/-7.5 degrees of RF(1.3GHz), ex+ey< 0.09p.m.rad,1% energy spread with beam energy ~2.4GeV W. Gai, W. Liu / ANL, J. Sheppard / SLAC

  15. Yield as function of drive beam energy & field

  16. Yield and polarization

  17. CLIC 20008 based on Linac scheme 326 klystrons 33 MW, 139 ms combiner rings Circumferences delay loop 72.4 m CR1 144.8 m CR2 434.3 m drive beam accelerator 2.38 GeV, 1.0 GHz CR1 CR1 1 km delay loop CR2 e- beam sent to Linac with optical cavities 326 klystrons 33 MW, 139 ms + 240 ns drive beam accelerator 2.38 GeV, 1.0 GHz 1 km delay loop CR2 decelerator, 24 sectors of 876 m BDS 2.75 km BDS 2.75 km BC2 BC2 245m 245m IP e+ main linac e- main linac , 12 GHz, 100 MV/m, 21.02 km TA R=120m TA R=120m 48.3 km CLIC 3 TeV booster linac, 9 GeV BC1 e- injector 2.4 GeV e+ injector, 2.4 GeV e-PDR 365m e- DR 365m e+PDR 365m e+DR 365m

  18. Linac scheme with Drive Beam g to e+ conv. target 2.4 GeV 100A e- beam g beam e+ beam 12 GHz V. Yakimenko and I. Pogorelski (BNL) proposal for ILC to be investigated for CLIC

  19. The CLIC Injector complex (Compton) e- Main Linac e+ Main Linac e- BC2 e+ BC2 12 GHz 12 GHz 9 GeV 48 km 3 TeV Laser Compton ring configuration Booster Linac 6.6 GeV 4 GHz e+ BC1 e- BC1 2.424 GeV 365 m 4 GHz 2.424 GeV 365 m 2 GHz e+ DR e- DR e+ PDR and Accumulator ring 2.424 GeV 365 m e- PDR 2.424 GeV 365 m Injector Linac 2.2 GeV 2 GHz RF gun e- Drive Linac 1.3 GeV Compton ring Laser Pre-injector Linac for e+ 200 MeV Pre-injector Linac for e- 200 MeV 2 GHz DC gun Polarized e- g e+ Target Stacking cavity Laser 2 GHz 2 GHz

  20. CLIC Compton scheme Compton configuration for polarized e+ and low e+/g yield 2.424 GeV e+ DR 2.424 GeV 450 turns makes 312 bunches with 4.4x109 e+/bunch e+ PDR and Accumulator ring C = 47 m, 156 ns/turn, 312 bunches with 6.2x1010 e-/bunch Injector Linac 2.2 GeV 2 GHz RF gun Drive Linac 1.3 GeV 156 ns x450 turns => 70 ms pulse length for both linacs 2 GHz Compton ring 2 GHz 50 Hz Pre-injector Linac for e+ 200 MeV g g (23-29 MeV)7x108 /turn/bunch Stacking cavity 9.8x106 pol. e+/turn/bunch e+ target 1 YAG Laser pulse

  21. CLIC Pre-Damping Ring optimization 1) The rms momentum spread at injection could be reduced by implementing: a) a bunch compressor at the entrance of the injector Linac b) a harmonic cavity which smooth the longitudinal distribution. 2) The transverse damping time should be ≈ 1 ms (in order to allow ≈ 10 damping times). It remains roughly 10 ms for the stacking. 3) The stacking efficiency could also be improved by putting 2 trains in the PDR.

  22. Compton e+ source parameters

  23. CLIC Compton ring E. Bulyak, P. Gladkikh / NCS KIPT

  24. CLIC Compton scheme Compton configuration for polarized e+ and high e+/g yield C = 47 m, 156 ns/turn, 312 bunches with 6.2x1010 e-/bunch RF gun Drive Linac 1.06 GeV 2 GHz Compton ring 2 GHz 50 Hz Pre-injector Linac for e+ 200 MeV g g (10 - 20 MeV)2.1x109g/turn/bunch Stacking cavity 5 x108 pol. e+/turn/bunch e+ target 1 YAG Laser pulse 592 mJ W sliced rod target 3 rad length => yield 0.48 e+ / g => Stacking simplified E. Bulyak / NCS KIPT

  25. Energy spread in CLIC Compton ring E = 1.06 GeV Double chicane 2 RF cavities => 150 MV Emittances after 15000 turns: eH = 21 nm . rad eV = 1 nm . rad Max energy spread ~ 1 % E. Bulyak, P. Gladkikh / NCS KIPT

  26. Photons from CLIC Compton ring K: 0.5 mrad Max polarization ~ 75 % I: 0.4 mrad Collimation angles G: 0.3 mrad E: 0.2 mrad E. Bulyak, P. Gladkikh / NCS KIPT C: 0.1 mrad

  27. Studies and R&D for Compton scheme Compton ring beam dynamics and design studies (NCS-KIPT, LAL, KEK, …) Laser source (see Posipol 2006, 2007 and 2008 for companies involved ) Laser stacking cavity (KEK, LAL, IHEP, Hiroshima,… ) Target and e+ capture (LAL, IPNL-Lyon, ANL, CERN, IHEP,… ) e+ stacking in Pre-Damping Ring and Damping Ring (CERN,… ) Collaboration on CLIC study for e+ sources is always welcome

  28. Conclusion 1) After the CLIC major changes in 2007, studies and optimization continue on the CLIC structures and possible changes could still occur. 2) For the unpolarized e+, a conventional source, based on channeling process, fulfills the CLIC requirements with a single target station. 3) For polarized e+ based on Undulator, studies continue. 4) For polarized e+ based on Compton back scattering, progress have been made (Ring & Linac) but several studies and R&D are still necessary. 5) The design of a CLIC e+ Pre-Damping Ringhas just started. The Compton ring seems the most promising option for CLIC polarized e+.

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