Alternate Tunings for the Linac Coherent Light Source Photoinjector

Conference · Fri Mar 17 04:00:00 EST 2006

OSTI ID:877453

Limborg-Deprey, C; Emma, P

The Linac Coherent Light Source (LCLS) is an x-ray free-electron laser (FEL) project based on the SLAC linac. The LCLS Photoinjector beamline has been designed to deliver 10-ps long electron bunches of 1 nC with a normalized projected transverse emittance smaller than 1.2 mm-mrad at 135 MeV. Tolerances and regulation requirements are tight for this tuning. Half of the total emittance at the end of the injector comes from the ''cathode emittance'' which is 0.7 mm-mrad for our nominal 1nC tuning. As the ''cathode emittance'' scales linearly with laser spot radius, the emittance will be dramatically reduced for smaller radius, but this is only possible at lower charge. In particular, for a 0.2 nC charge, we believe we can achieve an emittance closer to 0.4 mm-mrad. This working point will be easier to tune and the beam quality should be much easier to maintain than for the 1 nC case. In the second half of this paper, we discuss optimum laser pulse shapes. We demonstrate that the benefits of the ellipsoidal shapes seem to be important enough so that serious investigations should be carried out in the production of such pulses.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 877453
• Report Number(s): SLAC-PUB-11774
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
Accelerators
ACCPHY
ELECTRONS
FREE ELECTRON LASERS
LASERS
LIGHT SOURCES
LINEAR ACCELERATORS
PRODUCTION
REGULATIONS
STANFORD LINEAR ACCELERATOR CENTER
TUNING