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Title: Electron transport of a Linac Coherent Light Source (LCLS) using the SLAC linac

Conference ·
OSTI ID:10186516

A linac configuration providing a low emittance high peak current electron beam is under study for a potential Linac Coherent Light Source (LCLS) based on the SLAC accelerator. The parameters of the final electron bunch are nearing the technological limits of present accelerators in both transverse and longitudinal phase space. In this note we describe a layout of the RF gun, linac, and bunch compressors to deliver the required bunch properties. We consider a bunch that is generated by an rf gun and accelerated to 7 GeV in 900 m of SLAC linac structure before it enters the wiggler. We assume that the rf gun generates a gaussian beam with an energy of 10 MeV, a population N = 6 {times} 10{sup 9}e{sup {minus}}, an rms length {sigma}{sub z} = 0.5 mm, an rms energy spread {sigma}{sub {delta}} = 0.2%, and normalized rms emittances {gamma}{epsilon}{sub x,y} = 3 mm-mrad. At the end of the linac, we require that the peak current {cflx I} {approx_gt} 2.5 kA and the peak-to-peak energy spread {Delta}{delta} {approx_lt} 0.2%. To obtain the required high peak current, we need to compress the bunch length by a factor greater than 10. In deciding at what position in the linac to compress we need to consider three issues: the longitudinal wakefield in the linac, this increases the beam`s energy spread and is harder to compensate with short bunches, the transverse wakefield and rf deflections in the linac, these increase the transverse emittance of the beam and are more severe for long bunches, and the effects of phase and current jitter which will change the bunch length and therefore the peak current of the beam. In this paper, we will describe how we compress the bunch to meet these three criteria. Then, we will briefly describe the bunch compressor optics and finally we will mention some details specific to the SLAC site.

Research Organization:
Stanford Linear Accelerator Center, Menlo Park, CA (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC03-76SF00515
OSTI ID:
10186516
Report Number(s):
SLAC-PUB-6200; CONF-930511-428; ON: DE93040974; TRN: 93:023925
Resource Relation:
Conference: PAC `93: international particle accelerator conference,Washington, DC (United States),17-20 May 1993; Other Information: PBD: May 1993
Country of Publication:
United States
Language:
English