Experimental measurements of ultra-thin Bragg crystals for LCLS beam-sharing operation

Abstract

The successful lasing and operation of the LCLS hard X-ray FEL has brought tremendous interest to the user community spanning a wide range of scientific disciplines including physics, chemistry, structural biology, and material science. It created demand on beam time that is often left unfulfilled. Here we report experimental measurements of ultra-thin silicon single-crystal membranes for potentially beam-sharing the LCLS beam. The samples included the (111), (220), and (400) orientations with thicknesses ranging from 5 to 20 μm. Both high-resolution rocking curves and topographic data were first obtained using synchrotron X-rays, demonstrating near ideal diffraction qualities. Subsequent tests using the full LCLS beam revealed lattice distortions from beam-induced membrane vibrations, which were shown to be effectively reduced by ambient air and smaller membrane dimensions. High diffraction quality thin-diamonds in the (111) orientation are also being pursued as a parallel effort. Both approaches are paving a way for a practical beam-sharing implementation at LCLS in the near future. © 2013 IOP Publishing Ltd.