PSI scientists perform the worlds first hard X-FEL user experiment at SLAC

In October 2010, the commissioning phase of the X-Ray Pump-Probe experimental station at the Stanford LCLS source was finished. The very first user experiment in the hard x-ray range was carried out by a group of scientists from SLAC, the European XFEL and PSI under the lead of Christian David (PSI).

The experiment was dedicated to measuring the unique wave front properties of the LCLS using a hard x-ray grating interferometer. The extreme angular sensitivity and high efficiency made it possible to identify the effects of beam line components such as mirrors, monochromator crystals and focusing lenses. As the interferometer is capable of recording the wave front of a single laser pulse, it also provided insight into the effects of the accelerator and undulator settings on the LCLS wave front on a shot-to-shot basis. The technique is expected to develop into a useful diagnostics tool also for the European X-FEL and SwissFEL.

Part of the experimental run was dedicated to the testing of novel diffractive lenses developed in the Laboratory for Micro- and Nanotechnology of PSI. The focusing devices were made of diamond to survive the full radiation load of LCLS, and to provide a focal spot in the 100nm range. More information on these experiments can be found in the SLAC newsletter of October 22nd (see SLAC today)