SwissFEL: The Swiss X-ray Free Electron Laser

Abstract

The SwissFEL X-ray Free Electron Laser (XFEL) facility started construction at the Paul Scherrer Institute (Villigen, Switzerland) in 2013 and will be ready to accept its first users in 2018 on the Aramis hard X-ray branch. In the following sections we will summarize the various aspects of the project, including the design of the soft and hard X-ray branches of the accelerator, the results of SwissFEL performance simulations, details of the photon beamlines and experimental stations, and our first commissioning results.

Perspective: Opportunities for ultrafast science at SwissFEL

“…The SwissFEL 34 is located at the Paul Scherrer Institute (Fig. 1), which is a Swiss federal research laboratory and is the home to other national large-scale user facilities.…”

“…A major development in ultrafast X-ray science has been the advent of X-ray Free Electron Lasers (XFEL) 34 about ten years ago. This has not only boosted the capability of the existing ultrafast X-ray methods, but has opened the way to new ones that were hitherto impossible.…”

SwissFEL Aramis beamline photon diagnostics

“…The rapid development of X-ray free-electron laser (XFEL) facilities like FLASH, FERMI, LCLS, SACLA, PAL-XFEL and SwissFEL (Ackermann et al, 2007;Allaria et al, 2010;Emma et al, 2010;Ishikawa et al, 2012;Oberta et al, 2011;Milne et al, 2017;Ko et al, 2017) has brought a wave of new experiments that use the high intensities, short pulses or high coherence properties of the FEL X-ray pulses. However, both machine operators and users quickly noted that the pulse properties could and would change on a shot-to-shot basis, especially for those facilities that produced their FEL light using the self-amplified spontaneous emissions (SASE) process (Saldin & Kondratenko, 1980;Bonifacio et al, 1984), making the evaluation of the data gathered during an experiment more difficult.…”

Compact coherence enhancement by subharmonic self-seeding in X-ray free-electron laser facilities

“…We will now discuss the performance of the subharmonic selfseeding scheme by means of an example for the future soft X-ray beamline of SwissFEL (Milne et al, 2017;Prat et al, 2016), expected to generate FEL radiation between 0.65 and 5 nm. We have performed FEL simulations with the code Genesis 1.3 (Reiche, 1999) with the following electron-beam parameters: the energy is 3.15 GeV, the current profile is flat with a peak value of 3 kA and a total bunch length of 20 mm, the normalized transverse emittance is 300 nm, the slice energy spread is 350 keV [root mean square (RMS)], and the average function is about 5 m. The undulator beamline will initially consist of 16 undulator modules, with possible extensions in future upgrades.…”