CEPC injector beam dynamics Cai MENG Guoxi Pei
CEPC injector beam dynamics Cai MENG, Guoxi Pei , Xiaoping Li, Shilun PEI, Jingru Zhang, Xiangjian Wang Institute of High Energy Physics, CAS, Beijing
Outline 1 1 2 3 3 4 54 Introduction Electron linac Positron linac Summary & Plan
1. Introduction: CEPC Injector Main parameters: Parameter Symbol Unit Value Beam energy (e+/e-) Ee- / Ee+ Ge. V 6 f rep Hz 50~100 Repetition rate Bunch population (e+/e-) Energy spread (e +/e- ) Ne- / Ne+ σ e- bunch charge at target e- beam energy Emittance ε E 2× 10 10 <1× 10 -3 n. C 10 Ge. V 4 mm-mrad 0. 3
1. : CEPC Injector Layout ? Ø 频率选择 Ø Booster频率为 1300 MHz Ø 直线加速器的频率选2856. 75 MHz 其中,2856. 75 MHz=3. 25 MHz× 879,1300 MHz=3. 25 MHz× 400 MHz 3. 25 MHz
2. Electron linac Lattice ØBunching System ØSHB 1: 142. 8375 MHz ØSHB: 571. 35 MHz Ø S-band Buncher (1): 2856. 75 MHz ØFirst accelerating structure ØS-band accelerator (3): 2856. 75 MHz ~ 24 MV/m
2. Electron linac Bunching System 加发射度图 加包络图 加传输效率图 92% Emittance. Norm. rms=75 mm-mrad
2. Electron linac First accelerating structure 200 Me. V Emittance. Norm. rms=75 mm-mrad
3. Positron linac Ø Ø Lattice Positron beam distribution from target AMD: 5 T->0. 5 T The first two 1 m accelerator structure : r=15 mm 2856. 75 MHz The following 3 m accelerator structure: r=13 mm->9. 5 mm
3. Positron linac Distribution After Target After AMD After accelerator @ 200 Me. V
3. Positron linac Beam loss Aperture change Chopper
3. Positron linac Longitudinal profile
3. Positron linac Emittance ü Chicane ü Transport line ü Energy spread Ne+/Ne-=0. 68 Emittance. Norm. RMS=2500 mm-mrad Emittance. RMS@6 Ge. V=0. 21 mm-mrad
Summary&Plan ü Bunching System and first accelerating structure of electron linac have been proposed. (92%) ü Positron capture and accelerating have been discussed. (Emittance, Yield) ü Beam dynamic results ü ü ü High energy e-/e+ simulation including wakefield Chicane design for separating off electron Optimization of linac Transport line design ……
4 Ge. V VS 240 Me. V 4 Ge. V@13 mm 240 Me. V@8 mm
BEPCII ? Emittance. Norm. RMS=2500 mm-mrad 0. 36 n. C Emittance. RMS@1. 89 Ge. V=0. 66 mm-mrad BEPC: e+ 0. 1 n. C, 0. 24 mm-mrad at 1. 89 Ge. V
- Slides: 16