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Title: Optical Klystron Enhancement to SASE X-Ray FELs

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
901847
Report Number(s):
SLAC-PUB-12436
TRN: US0702685
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Conference: Prepared for 28th International Free Electron Laser Conference (FEL 2006), Berlin, Germany, 27 Aug - 1 Sep 2006
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; DESIGN; ELECTRON BEAMS; FREE ELECTRON LASERS; KLYSTRONS; LIGHT SOURCES; LINEAR ACCELERATORS; PERFORMANCE; RADIATIONS; SATURATION; WAVELENGTHS; WIGGLER MAGNETS; Accelerators,ACCPHY

Citation Formats

Ding, Y.T., Emma, P., Huang, Z., /SLAC, Kumar, V., and /Indore, Ctr. for Advanced Tech. Optical Klystron Enhancement to SASE X-Ray FELs. United States: N. p., 2007. Web.
Ding, Y.T., Emma, P., Huang, Z., /SLAC, Kumar, V., & /Indore, Ctr. for Advanced Tech. Optical Klystron Enhancement to SASE X-Ray FELs. United States.
Ding, Y.T., Emma, P., Huang, Z., /SLAC, Kumar, V., and /Indore, Ctr. for Advanced Tech. Mon . "Optical Klystron Enhancement to SASE X-Ray FELs". United States. doi:. https://www.osti.gov/servlets/purl/901847.
@article{osti_901847,
title = {Optical Klystron Enhancement to SASE X-Ray FELs},
author = {Ding, Y.T. and Emma, P. and Huang, Z. and /SLAC and Kumar, V. and /Indore, Ctr. for Advanced Tech.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Apr 02 00:00:00 EDT 2007},
month = {Mon Apr 02 00:00:00 EDT 2007}
}

Conference:
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  • The optical klystron enhancement to self-amplified spontaneous emission (SASE) free electron lasers (FELs) is studied in theory and in simulations. In contrast to a seeded FEL, the optical klystron gain in a SASE FEL is not sensitive to any phase mismatch between the radiation and the microbunched electron beam. The FEL performance with the addition of four optical klystrons located at the undulator long breaks in the Linac Coherent Light Source (LCLS) shows significant improvement if the uncorrelated energy spread at the undulator entrance can be controlled to a very small level. In addition, FEL saturation at shorter x-ray wavelengthsmore » (around 1.0 A) within the LCLS undulator length becomes possible. We also discuss the application of the optical klystron in a compact x-ray FEL design that employs relatively low electron beam energy together with a shorter-period undulator.« less
  • These proceedings represent papers presented at the X{minus}ray Free Electron Lasers Workshop held in Gargnano, Italy in June,1997. The workshop was sponsored by the University of Milan, DESY(Hamburg), and the US Department of Energy Laboratories SLAC and LBNL. Particular attention was given to the following topics: analytical and numerical modeling of free electron lasers, longitudinal and transverse coherence; fluctuations, spiking and photon statistics; and experimental projects status and results. There were 32 papers presented and 8 have been abstracted for the Energy Science and Technology database.(AIP)
  • Several linac driven X-ray Free Electron Lasers (XFELs) are being developed to provide high brightness photon beams with very short, tunable wavelengths. In this paper, three XFEL configurations are proposed that achieve LCLS-like performance using X-band linac drivers. These linacs are more versatile, efficient and compact than ones using S-band or C-band rf technology. For each of the designs, the overall accelerator layout and the shaping of the bunch longitudinal phase space are described briefly. During the last 40 years, the photon wavelengths from linac driven FELs have been pushed shorter by increasing the electron beam energy and adopting shortermore » period undulators. Recently, the wavelengths have reached the X-ray range, with FLASH (Free-Electron Laser in Hamburg) and LCLS (Linac Coherent Light Source) successfully providing users with soft and hard X-rays, respectively. FLASH uses a 1.2 GeV L-band (1.3 GHz) superconducting linac driver and can deliver 10-70 fs FWHM long photon pulses in a wavelength range of 44 nm to 4.1 nm. LCLS uses the last third of the SLAC 3 km S-band (2.856 GHz) normal-conducting linac to produce 3.5 GeV to 15 GeV bunches to generate soft and hard X-rays with good spatial coherence at wavelengths from 2.2 nm to 0.12 nm. Newer XFELs (at Spring8 and PSI) use C-band (5.7 GHz) normal-conducting linac drivers, which can sustain higher acceleration gradients, and hence shorten the linac length, and are more efficient at converting rf energy to bunch energy. The X-band (11.4 GHz) rf technology developed for NLC/GLC offers even higher gradients and efficiencies, and the shorter rf wavelength allows more versatility in longitudinal bunch phase space compression and manipulation. In the following sections, three different configurations of X-band linac driven XFELs are described that operate from 6 to 14 GeV. The first (LOW CHARGE DESIGN) has an electron bunch charge of only 10 pC; the second (OPTICS LINEARIZATION DESIGN) is based on optics linearization of the longitudinal phase space in the first stage bunch compressor and can operate with either a high (250 pC) or low (20 pC) bunch charge; and the third (LCLS INJECTOR DESIGN) is similar to LCLS but uses an X-band linac after the first stage bunch compressor at 250 MeV to achieve a final beam energy up to 14 GeV. Compared with LCLS, these X-band linacs are at least a factor of three shorter.« less
  • Recently, a 3D, polychromatic, nonlinear simulation code was developed to study the growth of nonlinear harmonics in self-amplified spontaneous emission (SASE) free-electron lasers (FELs). The simulation was applied to the parameters for each stage of the Advanced Photon Source (APS) SASE FEL, intended for operation in the visible, UV, and short UV wavelength regimes, respectively, to study the presence of nonlinear harmonic generation. Significant nonlinear harmonic growth is seen. Here, a discussion of the code development, the APS SASE FEL, the simulations and results, and, finally, the proposed experimental procedure for verification of such nonlinear harmonic generation at the APSmore » SASE FEL will be given.« less
  • We discuss the use of tapered undulators to enhance the performance of free-electron lasers (FELs) based upon self-amplified spontaneous emission (SASE), where the radiation tends to have a relatively broad bandwidth, limited temporal phase coherence, and large amplitude fluctuations. Using the polychromatic FEL simulation code GINGER, we numerically demonstrate the effectiveness of a tapered undulator for parameters corresponding to the existing Argonne low-energy undulator test line (LEUTL) FEL. We also study possible tapering options for proposed x-ray FELs such as the Linac Coherent Light Source (LCLS).