Auxiliary Optics For meV-IXS at SPring-8: KB, Analyzer Masks, Soller Slit & Screen, BPM

Abstract

This paper discusses several optical elements now in use at BL43LXU, the RIKEN Quantum NanoDynamics Beamline, of the RIKEN SPring-8 Center. BL43LXU is dedicated to meV-resolved inelastic x-rays scattering using spherical analyzers operating between 15.8 and 25.7 keV. The work described here is relevant for setups on the high-resolution spectrometer (10m two-theta arm) with resolution between 2.8 and 0.8 meV. Specific optics discussed include a multilayer Kirkpatrick-Baez (KB) mirror pair that focuses the full (~1x3mm2) beam at 17.79 keV to a 4.4 X 4.1 {\mu}m2 spot with ~60% throughput, two different types of Soller slits that help reduce backgrounds, masks for the analyzers that allow increased solid angle to be collected while preserving momentum resolution, and a diamond quadrant beam position monitor (BPM). These elements have been used and facilitate experiments in extreme conditions with diamond anvil cells, and liquid measurements at low momentum transfers, among other work.