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Title: Tuning of the LCLS Linac for User Operation

Authors:
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Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1261086
Report Number(s):
SLAC-PUB-16643
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Journal Name: Conf.Proc.C110328:2462-2464,2011; Conference: Particle Accelerator, 24th Conference (PAC'11) 28 Mar - 1 Apr 2011, New York, USA
Country of Publication:
United States
Language:
English
Subject:
Accelerators,ACCPHY

Citation Formats

Rzepiela, J., Loos, H., Akre, R., Brachmann, A., Decker, F.-J., Ding, Y., Emma, P., Fisher, A., Frisch, J., Gilevich, A., Hering, P., Huang, Z., Iverson, R., Lipkowitz, N., Nuhn, H.-D., Ratner, D., Smith, T., Turner, J., Welch, J., White, W., Wu, J., and /SLAC. Tuning of the LCLS Linac for User Operation. United States: N. p., 2016. Web.
Rzepiela, J., Loos, H., Akre, R., Brachmann, A., Decker, F.-J., Ding, Y., Emma, P., Fisher, A., Frisch, J., Gilevich, A., Hering, P., Huang, Z., Iverson, R., Lipkowitz, N., Nuhn, H.-D., Ratner, D., Smith, T., Turner, J., Welch, J., White, W., Wu, J., & /SLAC. Tuning of the LCLS Linac for User Operation. United States.
Rzepiela, J., Loos, H., Akre, R., Brachmann, A., Decker, F.-J., Ding, Y., Emma, P., Fisher, A., Frisch, J., Gilevich, A., Hering, P., Huang, Z., Iverson, R., Lipkowitz, N., Nuhn, H.-D., Ratner, D., Smith, T., Turner, J., Welch, J., White, W., Wu, J., and /SLAC. Thu . "Tuning of the LCLS Linac for User Operation". United States. doi:. https://www.osti.gov/servlets/purl/1261086.
@article{osti_1261086,
title = {Tuning of the LCLS Linac for User Operation},
author = {Rzepiela, J. and Loos, H. and Akre, R. and Brachmann, A. and Decker, F.-J. and Ding, Y. and Emma, P. and Fisher, A. and Frisch, J. and Gilevich, A. and Hering, P. and Huang, Z. and Iverson, R. and Lipkowitz, N. and Nuhn, H.-D. and Ratner, D. and Smith, T. and Turner, J. and Welch, J. and White, W. and Wu, J. and /SLAC},
abstractNote = {},
doi = {},
journal = {Conf.Proc.C110328:2462-2464,2011},
number = ,
volume = ,
place = {United States},
year = {Thu Jul 07 00:00:00 EDT 2016},
month = {Thu Jul 07 00:00:00 EDT 2016}
}

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  • In addition to its normal operation at 250pC, the LCLS has operated with 20pC bunches delivering X-ray beams to users with energies between 800eV and 2 keV and with bunch lengths below 10 fs FWHM. A bunch arrival time monitor and timing transmission system provide users with sub 50 fs synchronization between a laser and the X-rays for pump/probe experiments. We describe the performance and operational experience of the LCLS for short bunch experiments.
  • The authors describe the possible use of the SLAC linac to drive a unique, powerful, short wavelength Linac Coherent Light Source (LCLS). Using the FEL principle, lasing is achieved in a single pass of a high peak current electron beam through a long undulator by self-amplified-spontaneous-emission (SASE). The main components are a high-brightness electron RF gun with a photocathode, two electron bunch length compressors, the existing SLAC linac, beam diagnostics, and a long undulator combined with a FODO quadrupole focusing system. The RF gun, to be installed about 1 km from the end of the SLAC linac, would produce amore » single bunch of 6 x 10{sup 9} electrons with an invariant emittance of about 3 mm-mrad and a bunch length of about 500 {mu}m. That bunch is then accelerated to 100 MeV and compressed to a length of about 200 {mu}m. The main SLAC linac accelerates the bunch to 2 GeV were a second bunch compressor reduces the length to 30--40 {mu}m and produces a peak current of 2--3 kA. The bunch is then accelerated to 7--8 GeV and transported to a 50--70 m long undulator. Using electrons below 8 GeV, the undulator could operate at wavelengths down to 2 nm, producing about 10 GW peak power in sub-ps light pulses. At a linac repetition rate of 120 Hz, the average power is about 1 W. Linac operation at lower beam energies provides longer wavelength radiation. After the undulator, the beam is deposited in a dump. The LCLS light pulses are then distributed to multiple user stations using grazing incident mirrors. Length compression, emittance control, phase stability, FEL design criteria, and parameter tolerances are discussed. A demonstration experiment is also described which uses the SLAC linac and (possibly) the PALADIN undulator to study SASE to power saturation at wavelengths of 40--360 nm.« less
  • 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. Wemore » 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.« less
  • We describe the use of the SLAC linac to drive a unique, powerful. short wavelength Linac Coherent Light Source (LCLS). Operating as an FEL, lasing would be achieved in a single pass of a high peak current electron beam through a long undulator by self-amplified spontaneous emission (SASE). The main components are a high-brightness rf photocathode electron gun; pulse compressors; about 1/5 of the SLAC linac; and a long undulator with a FODO quadrupole focussing system. Using electrons below 8 GeV, the system would operate at wavelengths down to about 3 nm, producing {ge}10 GW peak power in sub-ps pulses.more » At a 120 Hz rate the average power is {approx} 1 W.« less
  • No abstract prepared.