SLAC, Menlo Park, California
The Linac Coherent Light Source (LCLS) is a SASE 1.5-15 Å x-ray Free-Electron Laser (FEL) facility under construction at SLAC[1], and presently in an advanced phase of commissioning. The injector, linac, and new bunch compressors were commissioned in 2007 and 2008, establishing the necessary electron beam brightness at 14 GeV. The final phase of commissioning, including the FEL undulator and the long transport line from the linac, began in November 2008, with first 1.5Å FEL light and saturation observed in mid-April 2009. We report on the accelerator, undulator, and FEL operations, including the new suite of x-ray diagnostics, which have just begun commissioning.
[1] J. Arthur et al. SLAC-R-593, April 2002.
RIKEN/SPring-8, Hyogo
To realize a compact FEL facility, a high frequency accelerator is indispensable to shorten the accelerator length. Then, a high-harmonic cavity used for nonlinear correction of a beam energy chirp encounters a technological difficulty of extremely high frequency RF system. In order to overcome this difficulty, a method of over-correction is proposed. In this method, a correction cavity is installed before any bunch compressors. Since the effective frequency of the correction cavity is increased as the electron bunch length compressed, the same RF frequency as main accelerators can be used for the correction cavity.
SLAC, Menlo Park, California
LBNL, Berkeley, California
We present experimental studies of the gain length and saturation levels from 1.5 nm to 1.5 Å for a variety of conditions at the Linac Coherent Light Source (LCLS). By disrupting the FEL process with an orbit kick, we are able to measure the X-ray intensity as a function of the undulator length. This kick method is cross-checked with the method of removing undulator sections. We measure the FEL gain length as a function of X-ray wavelength, laser-heater induced energy spread, beta function and peak electron current. We also study the X-ray intensity level and FEL-induced electron energy loss after saturation as a function of undulator K value to determine the optimal taper. The experimental results are compared to analytical formulae and simulations.
SINAP, Shanghai
The SDUV-FEL is a HGHG based FEL test facility under development at the SINAP campus. It was designed as a single stage HGHG-FEL driven by a 300MeV linac in the beginning, but now it is being integrated towards a two stages of cascading HGHG driven by a 160MeV linac. In this paper, we present the design progress and report the R&D status of the photo cathode RF gun, the magnetic bunch compressor and the undulators for this test facility.
RIKEN/SPring-8, Hyogo
XFEL/SPring-8 is SASE-FEL project aiming at generating intense coherent X-ray beam, which uses the thermionic gun with velocity bunching injector, 8 GeV normal conducting C-band accelerator, followed by 80 m long in-vacuum undulators [1]. Those key components have been verified at SCSS test accelerator. Target wavelength is 1 Å at 8 GeV beam and peak power level 20 GW. Machine construction is going well. Schedule is March 2009: Building construction completed. April 2009 - September 2010: Hardware installation. October 2010: High power operation of rf system and check. April 2011: Beam commissioning of X-ray FEL. We have the great opportunity to apply feedback in design from experiences in daily operation of the SCSS test accelerator (VUV SASE-FEL for user application). The talk covers the updated design work and current status of mass production of the 400 m long C-band accelerator system and undulators.
[1] http://www.riken.jp/XFEL/eng/index.html