LAL meeting on e+ studies, 25-26 Oct. 2010 Prospect for KEKB linac operation -Present status and near future- 26 October 2010 Tsuyoshi Suwada Accelerator Laboratory, KEK Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

LAL meeting on e+ studies, 25-26 Oct. 2010 Introduction The KEKB operation has been finished in the end of June 2010. It was decided to approve the Super KEKB project in KEK in the end of June based on “the Funding Program for Next Generation World-Leading Researchers” established within the Japan Society for the Promotion of Science (JSPS). One third　in total budget required for whole the construction was approved. Discussions for the upgrade and R&D plans towards the Super KEKB have been started just now. It is expected that the channeling experiments will be considerably disturbed during the construction of the Super KEKB. Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

experimental site KEKB LINAC Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010 3

Super KEKB Accelerator Complex Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

Mission of Injector Linac for four rings towards Super KEKB project Ring Energy Charge [GeV] [nC] PF (w top-up ope.) e- 2.5 0.1 PF-AR (w/o top-up ope.) e- 3 0.2 (w top-up ope.) ? e+? 4? 0.2 SKEKB (KEKB) LER e+ 4(←3.5) 4(←1) SKEKB (KEKB) HER e- 7(←8.0) 5(←1) Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

Linac Parameter change key upgrade parameters are in red letters Based on Kamitani, SuperKEKB Review 2010 Linac Parameter change key upgrade parameters are in red letters KEKB Achieved (e+/e-) SuperKEKB Required (e+/e-) beam energy 3.5 GeV / 8.0 GeV 4.0 GeV / 7.0 GeV stored current 1.6A / 1.2A 3.6A / 2.62A beam lifetime 150 min / 200 min 10 min / 10 min bunch charge 10 -> 1.0 nC / 1.0 nC 10 -> 4.0 nC / 5.0 nC # of bunches 2 / 2 beam emittance (ge)[1s] 2100 mm / 300 mm 10 mm / 20 mm energy spread sE/E 0.125 % / 0.05 % 0.07 % / 0.08 % bunch length sz 2.6 mm / 1.3 mm 0.5* mm / 1.3 mm e+ primary e– e+ e– primary e– e– Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010 *(assuming bunch compression after DR)

LAL meeting on e+ studies, 25-26 Oct. 2010 Injector Upgrade idea (e-) High intensity Low emittance Photo-cathode RF gun (e+) High intensity Low emittance AMD matching device (or Superconducting coil) + L-band Large-aperture capture section Damping Ring ( e–& e+ ) Misalignment, RF kick, CSR Alignment, etc. (PF, PF-AR) Pulse-by-pulse switching Timing control Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

LAL meeting on e+ studies, 25-26 Oct. 2010 Present KEKB Injector Based on Kamitani, SuperKEKB Review 2010 e– B A Pulse-by-pulse beam switching for HER, LER & PF Target bypass bump orbit (5 mm height) Compatible optical setting for different beam energies Switching of RF phases, ACC/DEC/STDBY timings & gun parameters Independent orbit control with pulse steerings for PF 2.5 GeV 0.1nC x 1 A1 gun 1.7 GeV @J-arc for HER 8.0 GeV 1nC x 2 C 1 target bypass bump orbit 2 3 4 5 3T gun moved from CT C-band module for AR 3.0 GeV 0.1nC x 1 e+ 10nC electron drive beam hit target at 4GeV 10% yield from electron to positron for 1nC positron Positron to be accelerated to 3.5GeV A1 gun B A for LER 3.5 GeV 1nC x 2 4.0 GeV 10nC x 2 C 1 2 3 4 5 e+ target & S-band capture section ECS (Energy-spread Compression System) Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

LAL meeting on e+ studies, 25-26 Oct. 2010 SuperKEKB Injector Based on Kamitani, SuperKEKB Review 2010 e– B A low emittance RF gun for PF 2.5 GeV 0.1nC x 1 RF gun emittance growth ? in e– / e+ beams 1.7 GeV @J-arc for HER 7.0 GeV 5nC x 2 C 1 2 3 4 5 target bypass bump orbit e- bypass line for DC separation bend for AR e– or e+ ? e+ Present A1 gun for 10nC e– beam Damping ring A1 gun 1.1 GeV@DR B A Nominally S-band acceleration 160MeV / RF unit (nominal) + 8m C-band at 4-4 Target moved to 1-4 for e+ energy margin new matching dev. & L-band capt. section for e+ intensity upgrade for LER 4.0 GeV 4nC x 2 C 1 2 BCS ECS 3 4 5 3.5 GeV 10nC x 2 e+ target, matching dev. & L-band capture section C-band module x 2 ECS (Energy-spread Compression System) Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

Injector upgrade gross plan (not yet fixed) JFY2010 JFY2011 JFY2012 JFY2013 JFY2014 KEKB oper. HER, LER upgrade SuperKEKB commissioning DR component fabrication DR tunnel construction Conflicting items Installation DR building construction DR commissioning 1 Apr. 2011 31 Jan. 2012 DR-Inj Connection No beam delivering 8-GeV beam delivering under limited condition e+ matching device R&D e+ matching device & capture section construction e+ beam commissioning L-band and LAS development L-band & LAS module construction RF-gun & laser system design study @A1&elsewhere e- beam commissioning Full-spec RF gun and laser Establish at A1 A1 gallery extension Laser alignment study Actual alignment system Keep PF, AR injection with 3T gun and/or A1 gun, then add SuperKEKB from JFY2014 Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

LAL meeting on e+ studies, 25-26 Oct. 2010 Summary Discussions on the construction & R/D plans for the upgrade of the KEKB injector towards the Super KEKB has been started just now (October 2010). The tentative plan has been now developed and maybe it will be fixed by the end of 2010. A lot of R&D works will start soon. It is expected at least that the channeling experiments are not available during the term from 1 Apr. 2011 to 31 Jan. 2012, and even after this term it will be considerably limited for the use of 8-GeV electron beams up to the start of the commissioning which will be scheduled at the middle of FY2013. The next scheduled chance to perform the experiment is the beginning of Jan. 2011. Another chance is not clear at present. Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010

KEKB Accelerator Complex (+PF, AR) Tsuyoshi Suwada/KEKB Linac LAL meeting on e+ studies, 25-26 Oct. 2010