Beam Dynamics Study of X-Band Linac Driven X-Ray FELS

Conference · Tue Dec 13 00:00:00 EST 2011 · Conf.Proc.C110904:3130-3132,2011

OSTI ID:1032762

Adolphsen, C.; Limborg-Deprey, C.; Raubenheimer, T. O.; Wu, J.; Sun, Y.

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 shorter 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.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 1032762
• Report Number(s): SLAC-PUB-14570; TRN: US1200554
• Journal Information: Conf.Proc.C110904:3130-3132,2011, Conference: Presented at the 2nd International Particle Accelerator Conference (IPAC-2011), San Sebastian, Spain, 4-9 Sep 2011
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATION
ACCELERATORS
BEAM DYNAMICS
BRIGHTNESS
COMPRESSION
COMPRESSORS
ELECTRON BEAMS
ELECTRONS
FREE ELECTRON LASERS
LASERS
LIGHT SOURCES
LINEAR ACCELERATORS
OPTICS
PHASE SPACE
PHOTON BEAMS
PHOTONS
STANFORD LINEAR ACCELERATOR CENTER
WAVELENGTHS
WIGGLER MAGNETS
Accelerators
ACCPHY