Diamond channel-cut crystals for high-heat-load beam-multiplexing narrow-band X-ray monochromators

Abstract

Next-generation high-brilliance X-ray photon sources call for new X-ray optics. Here we demonstrate the possibility of using monolithic diamond channel-cut crystals as high-heat-load beam-multiplexing narrow-band mechanically stable X-ray monochromators with high-power X-ray beams at cutting-edge high-repetition-rate X-ray free-electron laser (XFEL) facilities. The diamond channel-cut crystals fabricated and characterized in these studies are designed as two-bounce Bragg reflection monochromators directing 14.4 or 12.4 keV X-rays within a 15 meV bandwidth to 57Fe or 45Sc nuclear resonant scattering experiments, respectively. The crystal design allows out-of-band X-rays transmitted with minimal losses to alternative simultaneous experiments. Only ≲2% of the incident ∼100 W X-ray beam is absorbed in the 50 µm-thick first diamond crystal reflector, ensuring that the monochromator crystal is highly stable. Other X-ray optics applications of diamond channel-cut crystals are anticipated.

Design, fabrication, and characterization of x-ray optics for the cavity-based x-ray free-electron laser project

“…However, some defects or dislocations can also be seen on this and other characterized and selected diamond crystals. Using these results, the best region on each diamond (working areas) is identified and the crystal is cut with a laser 24,35,36 beam according to the pattern shown in Fig. 2 in such a way that the crystal defects are outside the working areas.…”