Simulation studies on ILC BC and ML with SLEPT Dou WANG (IHEP), - PowerPoint PPT Presentation

Simulation studies on ILC BC and ML with SLEPT Dou WANG (IHEP), Kiyoshi KUBO (KEK) ICWS10 & ILC10, March 26-30, IHEP,China,2010

Code upgrade-1 • SLEPT used to fix relative longitudinal position for saving time of wakefield calculations. It has been upgraded to include longitudinal motion so that we can simulate both RF section and wiggler section of 2-stage BC together. (Also ML can be included.) Two types sections in the beam line: – Normal section: Z does not change. Wakefields exist. – Special section: Z can change. No wakefields. We add new element-real bending megnets. For special section beginning: slice beam particle beam (add Z to each macro-particle) end: particle beam slice beam; reset wakefields for slice beam.

Code upgrade-2 • DFS by RF phase tuning is included in the new program. ( ) ∑ ( ) ( ) ( ) 2 ϕ − + 2 { w y y 0 y 0 } one test beam: i i i i ( ) ∑ ( ) ( ) ( ) 2 + ϕ − − ϕ + 2 two test beams: { w y y y 0 } i i i i

Code upgrade-3 • Cryomodule misalignment is included. In the past, all the elements were aligned w.r.t. survey line or perfect beam line independently. Now the cavities, quadrupoles and BPMs in cold regions are aligned w.r.t. cryomodules, and the elements in warm regions are aligned independently. “standard” set of errors in cold regions error With respect to Quad offset 300 um cryomodule Quad roll 300 urad cryomodule Cavity offset 300 um cryomodule Cavity pitch 300 urad cryomodule BPM offset 10 um Attached Quad Cryomodule offset 200 um Survey line Cryomodule 20 urad Survey line

1. Simulations on 2-stage BC

Bunch length and natural emittance 0. 006 ) 0. 005 m ( No error , h 0. 004 t g no correction . n e 0. 003 l h 0.000820 c 0. 002 n 0.000326 u b 0. 001 0 0 200 400 600 800 1000 1200 s (m ) 2. 010E- 08 ) m ( 2. 008E- 08 e c n a 2. 006E- 08 t t i m e 2. 004E- 08 l a r u 2. 002E- 08 t a n 2. 000E- 08 0 200 400 600 800 1000 1200 s ( m )

DFS by whole linac RF phase tuning-1 • The DFS by RF phase tuning before each section is very sensitive to BPM offset and BPM resolution. The results are reasonable. Through changing the RF phase, the energy differrence between the normal beam and test beam is not big enough. • Solution: changing RF phase in whole linac rather than just before each section.

DFS by whole linac RF phase tuning-2 △ ϕ =0.2 rad, weight =5000, random seeds=20 2. 014 2. 09 ) w hol e l i nac w hol e l i nac m ) 2. 08 m 2. 012 8 w hol e l i nac ( t w o t est beam s) w hol e l i nac ( t w o t est beam s) - 8 0 - 2. 07 1 0 2. 01 ( 1 ( 2. 06 e c e n c 2. 008 a 2. 05 n t a t t i 2. 04 t 2. 006 m i e m e 2. 03 d 2. 004 d e t e 2. 02 c t c e 2. 002 e r r r 2. 01 o r o c 2 c 2 0 200 400 600 800 1000 1200 0 100 200 300 400 500 600 Q uad of f set Q uad r ot at i on ( ur ad)

DFS by whole linac RF phase tuning-3 △ ϕ =0.2 rad, weight =5000, random seeds=20 2. 35 14 w hol e l i nac ) w hol e l i nac m ) 2. 3 w hol e l i nac ( t w o t est beam s) m 8 12 w hol e l i nac ( t w o t est beam s) - 8 0 - 1 0 ( 2. 25 1 ( 10 e c e n c a 2. 2 n t a t t 8 i t m i 2. 15 e m e d e 6 d t e c 2. 1 t e c r e r r o r 4 2. 05 c o c 2 2 0 200 400 600 800 1000 1200 0 100 200 300 400 500 600 cavi t y of f set ( um ) cavi t y t i l t ( ur ad) Cavity tilt can not be cured by DFS!

DFS by whole linac RF phase tuning-4 △ ϕ =0.2 rad, weight =5000, random seeds=20 2. 9 ) 3. 8 ) m m w hol e l i nac w hol e l i nac 2. 8 8 3. 6 8 - - 0 w hol e l i nac ( t w o t est beam s) w hol e l i nac ( t w o t est beam s) 0 1 2. 7 1 3. 4 ( ( e 2. 6 e 3. 2 c c n n a a 2. 5 t 3 t t t i i 2. 4 m 2. 8 m e e d 2. 3 d 2. 6 e e t t c c 2. 2 2. 4 e e r r r r 2. 1 2. 2 o o c c 2 2 0 100 200 300 400 500 600 0 1 2 3 4 5 6 BPM of f set BP M r esol ut i on ( um )

DFS with only cavity tilt RF phase tuning (one test beam) ， cavity tilt =300 um, random seeds=20 4 ) m 8 - 0 1 3. 5 ( e c n a t 3 t i m R Fphase=0. 05 e d R Fphase=0. 1 e 2. 5 t c R Fphase=0. 2 e r R Fphase=0. 3 r o c R Fphase=0. 4 2 1 10 100 1000 10000 w ei ght ) m 12 2. 63 8 - 2. 62 0 10 t 1 2. 61 ( h g 2. 6 i e 8 c e 2. 59 n w a t m 2. 58 6 t u m i 2. 57 m i e t 4 2. 56 p m o u 2. 55 m 2 i 2. 54 n i m 2. 53 0 0 0. 1 0. 2 0. 3 0. 4 0. 5 0 0. 1 0. 2 0. 3 0. 4 0. 5 R F phase R F phase Cavity tilt reject large weight.

DFS with all errors except for cavity tilt RF phase tuning (one test beam) ， random seeds=20 Quad offset error=300 µ m Quad rotation=300um Cavity offset error=300 µ m BPM offset=300 µ m BPM resolution=1 µ m ) 30 ) m 3. 4 m R Fphase=0. 05 8 8 - - 25 0 3. 2 0 R Fphase=0. 1 1 1 ( ( R Fphase=0. 2 3 e 20 e c c n n R Fphase=0. 3 a 2. 8 a t 15 t t R Fphase=0. 4 i t m i 2. 6 e m 10 e d e 2. 4 m t c u e m 5 r 2. 2 i r n o i c m 2 0 1 10 100 1000 10000 0 0. 1 0. 2 0. 3 0. 4 0. 5 w ei ght phase Without cavity tilt, the final corrected emittance can be controlled to 3.2 nm for BC.

DFS with all errors-1 RF phase tuning (one test beam) ， random seeds=20 Standard errors: Quad offset error=300 µ m R Fphase=0. 05 Quad rotation=300um 27 ) R Fphase=0. 1 m Cavity offset error=300 µ m 8 R Fphase=0. 2 - 0 22 1 Cavity tilt=300 µ rad R Fphase=0. 3 ( e R Fphase=0. 4 c n BPM offset=300 µ m a 17 R Fphase=- 0. 1 t t i BPM resolution=1 µ m m R Fphase=- 0. 2 e d R Fphase=- 0. 3 12 e t c R Fphase=- 0. 4 e r r o 7 c 2 1 10 100 1000 10000 w ei ght 5. 5 100000 ) d 5 m e t t h 8 c g 4. 5 - e i 10000 0 r e 1 r w 4 ( o m c e u c 3. 5 m m n i u a t m 1000 t 3 p i t o n i i m 2. 5 m e 2 100 -0. 4 - 0. 3 - 0. 2 -0. 1 0 0. 1 0. 2 0. 3 0. 4 - 0. 4 - 0. 3 - 0. 2 - 0. 1 0 0. 1 0. 2 0. 3 0. 4 R F phase change ( r ad) R F phase change ( r ad)

DFS with all errors-2 △ ϕ =0.4 rad, weight=1000. 6. 5E- 08 M O D D FS =1 ) m 6. 0E- 08 ( R F phase t uni ng ( one t est beam ) 5. 5E- 08 e c R F phase t uni ng ( t w o t est beam s) n 5. 0E- 08 a t t 4. 5E- 08 i m 4. 0E- 08 e d 3. 5E- 08 e t c 3. 0E- 08 e r r 2. 5E- 08 o c 2. 0E- 08 0 200 400 600 800 1000 1200 s ( m ) * MODDFS=1: Both initial beam energy and accelerating gradient are reduced by 10% With all the errors, the final emittance growth will be 13 nm for BC.

The effect of coupler RF kick and coupler wakefield on BC-1 1-to-1 ， no misalignment, random seeds=40 3. 2E- 08 R F ki ck onl y ) m coupl er w ake onl y ( 3. 0E- 08 e coupl er w ake+R F ki ck c A. Latina’s result (PLACET) n a 2. 8E- 08 t t i m 2. 6E- 08 e d e 2. 4E- 08 t c e r Final emittance growth=3.28 nm 2. 2E- 08 r o c 2. 0E- 08 0 200 400 600 800 1000 1200 s ( m ) Our results for the peak are smaller than A. Latina’s. ?? The final emittance growth is 3.86 nm by our result.

The effect of coupler RF kick and coupler wakefield on BC-2 5. 0E- 08 BC2 3. 2E - 08 R F ki ck onl y e c R F ki ck onl y n a ) coupl er w ake onl y t w ake onl y 4. 5E- 08 t m i 3. 0E - 08 w +R Fk ( m e coupl er w ake+R F ki ck e l a c c 4. 0E- 08 i n t 2. 8E - 08 a r e t v t d 3. 5E- 08 i e m t 2. 6E - 08 ) c e m Last year e ( r r d o 3. 0E- 08 c e t 2. 4E - 08 n c o i e s r r 2. 5E- 08 e r p s o 2. 2E - 08 i c d r 2. 0E- 08 a e n 2. 0E - 08 i l 1. 5E- 08 0 200 400 600 800 1000 1200 0 100 200 300 400 500 600 700 s ( m ) s ( s) • We had different lattice this year, related to the beam loading by short-range wakefield . • Different lattice give different results.

2. Simulations on curved ML

Fast movement-Quad position No orbit correction , random seeds=50 8 0. 4 - 2. 6 t 0 e 1 s 0. 35 ( f 2. 5 f e o 0. 3 c n Y 2. 4 a 0. 25 t e t v ) i 0. 2 m i 2. 3 m t e a 0. 15 l d e 2. 2 e r t 0. 1 c S e 2. 1 M j 0. 05 R o r 0 p 2 0 0. 005 0. 01 0. 015 0. 02 0. 025 0. 03 0. 035 0 0. 1 0. 2 0. 3 0. 4 0. 5 0. 6 0. 7 Q uad of f set er r or ( um ) Q uad of f set er r or ( um ) Random quadrupole position jitter torlerance (about 3% luminosity reductuion): For 0.14 σ RMS beam offset: 12 nm For 0.063 ε 0 emittance growth: 200 nm

Fast movement-cavity position No orbit correction , random seeds=50 8 0. 5 2. 7 - 0 1 0. 45 t ( 2. 6 e s 0. 4 e f c f 2. 5 n o 0. 35 a t Y 2. 4 0. 3 t ) e i m v m 0. 25 i e 2. 3 t a 0. 2 d l e e 2. 2 t r 0. 15 c S e 2. 1 M 0. 1 j R o r 0. 05 p 2 0 0 100 200 300 400 0 10 20 30 40 50 60 70 80 cavi t y of f set er r or ( um ) cavi t y of f set ( um ) Random cavity position jitter torlerance (about 3% luminosity reductuion): For 0.14 σ RMS beam offset: 22 um For 0.063 ε 0 emittance growth: 130 um