16 th June 2008 POSIPOL 2008L. Rinolfi / CERN 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
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN The CLIC Injector complex in 2008 e - gun 3 TeV Base line configuration Laser DC gun Polarized e - Pre-injector Linac for e MeV e - / Target Pre-injector Linac for e MeV Primary beam Linac for e - 5 GeV Injector Linac 2.2 GeV e + DR e + PDR Booster Linac 6.6 GeV 4 GHz e + BC1 e - BC1 e + BC2 e - BC2 e + Main Linac e - Main Linac 12 GHz, 100 MV/m, 21 km 2 GHz e - DR e - PDR 2 GHz 4 GHz 12 GHz 9 GeV 48 km 30 m GeV e Target AMD GeV 365 m GeV 365 m 473 m 228 m 365 m
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN NLC (1 TeV) CLIC 2008 (3 TeV) ILC (Nominal) Energy E GeV8 915 Bunch population N Nb bunches / train n b Bunch spacing t b ns (6 RF periods) 369 Train length t pulse ns Emittances x, y nm, nm.rad3300, , , 24 rms bunch length z mm rms energy spread E 0.68 (3.2 % FW) Repetition frequency f rep Hz Beam power P kW Main beam parameters comparison At the entrance of the Main Linac for e - and e +
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN # of bunches per pulse # of positrons per bunch # of positrons per pulse Total charge (nC) Current (A) Exit of BC2 = Entrance of Main Linac ( 9 GeV) 3124 x x At exit Pre- Damping ring (2.424 GeV) x x At exit Injector Linac (2.424 GeV) x x At exit Pre- Injector Linac (200 MeV) x x Assuming ~ 90 % efficiency between the PDR and the Main Linac CLIC parameters relevant for e + source Repetition frequency 50 Hz Total pulse length 156 ns Assuming ~ 70 % capture efficiency in the PDR Assuming ~ 95 % efficiency between the Pre-Injector and the Injector Linac
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Conventional e + source based on channelling A e - beam impinges on the crystal: - energy of 5 GeV - beam size of 2.5 mm crystal amorphous e-e- e-e- e+e+ Yield: 0.9 e + / e 200 MeV R. Chehab, V. Strakovenko, A. Variola, A. Vivoli / LAL A crystal e+ source : - a 1.4 mm thick W crystal oriented along axis - a 10 mm thick W amorphous disk Charged particles are swept off after the crystal:only (> 2MeV) impinge on the amorphous target. The distance between the 2 targets is 2 meters. e-e- e+e+
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN CLIC Channeling e + source ParameterUnitCLIC Primary e - Beam EnergyGeV5 N e - /bunch N bunches / pulse-312 N e - / pulse Pulse lengthns156 Repetition frequencyHz50 Beam powerkW94 Linac frequencyGHz2 Beam radius (rms)mm2.5 Bunch length (rms)mm0.3 ParameterUnit TargetCrystalAmorph. MaterialWW Lengthmm1.410 Beam power deposited kW Deposited P / Beam Power %0.28 Pulse energy density GeV/mm Energy lost per volume 10 9 GeV/mm Peak energy deposition density (PEDD) J/g Yield (at 200 MeV): 0.9 e + / e - Experimental limit found at SLAC: PEDD = 35 J/g
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Beam parameters with channeling Positrons after capture section at 270 MeV ParameterUnitCLIC Energy (E)GeV0.270 No. of e + / bunch (N) Bunch length (rms)mm8 Energy Spread (rms)%5 Longitudinal emittance ( l ) eV.m10 5 Horizontal emittance ( x ) / ( x ) mm. mrad12 / 6300 Vertical emittance ( y ) / ( y ) mm. mrad12 / 6300 Q ~ 1 nC See R. Chehab talk at this workshop
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN ParameterUnit Conventional target CERN simulations Channeling LAL simulations Energy (E)GeV No. of e + / bunch (N) Bunch length (rms)mm58 Energy Spread (rms)%3.55 Horizontal emittance ( x ) mm. mrad Vertical emittance ( y ) mm. mrad Beam parameters comparison Accelerating gradient MV/m Positrons after capture section at the end of the pre-injector linac
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Longitudinal phase space at 2.4 GeV Energy spread = 65 MeV p/p (rms) = 2.7 % If PDR acceptance is p/p = ± 1 % = > 82 % capture efficiency e+e+
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Required CLIC Pre-Damping Ring PARAMETERPDR energy [GeV]2.424 circumference [m]365.2 bunch population [10 +9 ]4.4 bunch spacing [ns]0.5 number of bunches/train312 number of trains1 store time/train [ms]20 rms bunch length [mm] at injection5 rms momentum spread [%] at injection2.7 hor. normalised emittance [ m] at ejection63 ver. normalised emittance [ m] at ejection1.5 hor./ver./ lon./ damping times [ms]1 / 1 / 0.5 number of RF cycles1 repetition rate [Hz]50 RF frequency [GHz]2 > ± 1% as small as possible
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN CLIC base line configuration for e + source e - / Target Primary beam Linac for e - 5 GeV 2 GHz e Target AMD Pre-injector Linac for e MeV Thermionic gun 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. 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.
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN 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
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Undulator K = 0.75 u = 1.5 cm L = 100 m Pre-Injector Linac G = 20 MV/m E = 200 MeV f RF = 1.5 GHz B = 0.5 T Injector Linac G = 17 MV/m E = GeV f RF = 1.5 GHz f rep = 50 Hz CLIC 2007 based on undulator scheme 250 GeV Cleaning chicane NC Linac 2.2 GeV To the IP e - beam Ti alloy 450 m e+e+ e+e+
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN 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), x+ y< 0.09 m.rad,1% energy spread with beam energy ~2.4GeV Optimizing for yield W. Gai, W. Liu / ANL, J. Sheppard / SLAC
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Yield as function of drive beam energy & field
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Yield and polarization
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN e + injector, 2.4 GeV e - injector 2.4 GeV CLIC 3 TeV e + main linac e - main linac, 12 GHz, 100 MV/m, km BC2 BC1 e + DR 365m e - DR 365m booster linac, 9 GeV decelerator, 24 sectors of 876 m IP BDS 2.75 km BDS 2.75 km 48.3 km drive beam accelerator 2.38 GeV, 1.0 GHz combiner rings Circumferences delay loop 72.4 m CR m CR m CR1 CR2 delay loop 326 klystrons 33 MW, 139 s 1 km CR2 delay loop drive beam accelerator 2.38 GeV, 1.0 GHz 326 klystrons 33 MW, 139 s 1 km CR1 TA R=120m TA R=120m 245m e + PDR 365m e - PDR 365m Linac with optical cavities e- beam sent to ns CLIC based on Linac scheme
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Linac scheme with Drive Beam ParametersCLIC Energy2.38 GeV Current101 A Nb bunches / train2904 e - Bunch population5 x Bunch charge8.4 nC Repetition fequency50 Hz 2.4 GeV 100A e - beam beam e + beam to e + conv. target V. Yakimenko and I. Pogorelski (BNL) proposal for ILC to be investigated for CLIC 12 GHz
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN The CLIC Injector complex (Compton) 3 TeV Laser Compton ring configuration Laser DC gun Polarized e - Pre-injector Linac for e MeV e + Target Pre-injector Linac for e MeV Injector Linac 2.2 GeV e + DR GeV 365 m Booster Linac 6.6 GeV 4 GHz e + BC1 e - BC1 e + BC2 e - BC2 e + Main Linac e - Main Linac 2 GHz e - DR e - PDR 2 GHz 4 GHz 12 GHz 9 GeV 48 km e - Drive Linac 1.3 GeV Compton ring e + PDR and Accumulator ring 2 GHz RF gun Stacking cavity GeV 365 m GeV 365 m GeV 365 m
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN e + target Pre-injector Linac for e MeV Injector Linac 2.2 GeV e + DR GeV 2 GHz GeV Drive Linac 1.3 GeV Compton ring e + PDR and Accumulator ring 2 GHz 50 Hz CLIC Compton scheme Compton configuration for polarized e + and low e + / yield RF gun 1 YAG Laser pulse 2 GHz Stacking cavity 450 turns makes 312 bunches with 4.4x10 9 e + /bunch C = 47 m, 156 ns/turn, 312 bunches with 6.2x10 10 e - /bunch 9.8x10 6 pol. e + /turn/bunch (23-29 MeV) 7x10 8 /turn/bunch 156 ns x450 turns => 70 s pulse length for both linacs
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN PARAMETERPDR energy [GeV]2.424 number of trains1 rms momentum spread [%] at injection2.7 hor./ver./ lon./ damping times [ms]1 / 1 / 0.5 repetition rate [ms]20 RF frequency [GHz]2 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.
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Compton e + source parameters ParametersCLIC 2007CLIC 2008ILC Energy1.3 GeV1.06 GeV1.3 GeV Circumference68 m47 m277 m RF frequency1.5 GHz2 GHz650 MHz Bunch spacing0.20 m0.15 m0.923 m Nb bunches stored e - Bunch population6.2 x Nb optical cavities1130 Photons/bunch/turn0.7 x x x 10 10
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN CLIC Compton ring E. Bulyak, P. Gladkikh / NCS KIPT ParametersCLIC 2007CLIC 2008 Energy1.3 GeV1.06 GeV RF frequency1.5 GHz2 GHz RF voltage50 MV150 MV e - Bunch charge10 nC e - bunch length at IP5 mm Synchrotron losses400 keV/turn213 keV/turn Laser photon energy1.164 eV Laser rms pulse length0.9 mm Laser rms pulse radius0.005 mm Laser pulse energy600 mJ592 mJ Full cycle (turns)15000
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN e + target Pre-injector Linac for e MeV 2 GHz Drive Linac 1.06 GeV Compton ring 2 GHz 50 Hz CLIC Compton scheme Compton configuration for polarized e + and high e + / yield RF gun 1 YAG Laser pulse Stacking cavity C = 47 m, 156 ns/turn, 312 bunches with 6.2x10 10 e - /bunch 5 x10 8 pol. e + /turn/bunch ( MeV) 2.1x10 9 /turn/bunch 592 mJ W sliced rod target 3 rad length => yield 0.48 e + / => Stacking simplified E. Bulyak / NCS KIPT
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Energy spread in CLIC Compton ring E = 1.06 GeV Double chicane 2 RF cavities => 150 MV Emittances after turns: H = 21 nm. rad V = 1 nm. rad Max energy spread ~ 1 % E. Bulyak, P. Gladkikh / NCS KIPT
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN Photons from CLIC Compton ring E. Bulyak, P. Gladkikh / NCS KIPT K: 0.5 mrad I: 0.4 mrad G: 0.3 mrad E: 0.2 mrad C: 0.1 mrad Collimation angles Max polarization ~ 75 %
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN 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
16 th June 2008 POSIPOL 2008L. Rinolfi / CERN 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 Ring has just started. The Compton ring seems the most promising option for CLIC polarized e +.