Coupler Design for the LCLS Injector S-Band Structures

Conference · Fri Mar 03 00:00:00 EST 2006

OSTI ID:877217

Li, Z; Bentson, L D; Chan, J; Dowell, D H; Limborg-Deprey, C; Schmerge, J F; Schultz, D C; Xiao, L

The LCLS injector is required to provide a 1-nC, 10-ps bunch with a normalized rms transverse projected emittance of less than 1 micron. The LCLS beam is generated and accelerated in a 1.6-cell S-band RF gun at 120 MV/m up to 6 MeV. The gun is followed by two SLAC 3-m S-band accelerator structures to further accelerate the beam to 135 MeV which moves the beam out of the space-charge dominated regime. In the SLAC S-band structures, the RF power feed is through a single coupling-hole (single-feed coupler) which results in a field asymmetry. The time dependent multipole fields in the coupler induce a transverse kick along the bunch and cause the emittance to increase above the LCLS specification. To meet the stringent emittance requirements for the injector, the single-feed couplers will be replaced by a dual-feed racetrack design to minimize the multipole field effects. We will present detailed studies of the multipole fields in the SLAC linac RF coupler and the improvements with the dual-feed ractrack design using the parallel finite element S-parameter solver S3P.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 877217
• Report Number(s): SLAC-PUB-11728
• Conference Information: Prepared for Particle Accelerator Conference (PAC 05), Knoxville, Tennessee, 16-20 May 2005
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
Accelerators
ACCPHY
ASYMMETRY
DESIGN
LINEAR ACCELERATORS
MULTIPOLES
SPACE CHARGE
STANFORD LINEAR ACCELERATOR CENTER