All-diamond optical assemblies for a beam-multiplexing X-ray   monochromator at the Linac Coherent Light Source
  A double-crystal diamond (111) monochromator recently implemented at the Linac Coherent Light Source (LCLS) enables splitting of the primary X-ray beam into a pink (transmitted) and a monochromatic (reflected) branch. The first monochromator crystal with a thickness of 100 um provides sufficient X-ray transmittance to enable simultaneous operation of two beamlines. Here we report on the design, fabrication, and X-ray characterization of the first and second (300-um-thick) crystals utilized in the monochromator and the optical assemblies holding these crystals. Each crystal plate has a region of about 5 X 2 mm2 with low defect concentration, sufficient for use in X-ray optics at the LCLS. The optical assemblies holding the crystals were designed to provide mounting on a rigid substrate and to minimize mounting-induced crystal strain. The induced strain was evaluated using double-crystal X-ray topography and was found to be small over the 5 X 2 mm2 working regions of the crystals. 
S. Stoupin, S.A. Terentyev, V.D. Blank, Yu.V. Shvyd'ko, K.Goetze, L.   Assoufid, S.N. Polyakov, M.S. Kuznetsov, N.V. Kornilo...
physics.optics cond-mat.mtrl-sci