High-Precision X-ray Total Scattering Measurements Using a High-Accuracy Detector System

Abstract

The total scattering method, which is based on measurements of both Bragg and diffuse scattering on an equal basis, has been still challenging even by means of synchrotron X-rays. This is because such measurements require a wide coverage in scattering vector Q, high Q resolution, and a wide dynamic range for X-ray detectors. There is a trade-off relationship between the coverage and resolution in Q, whereas the dynamic range is defined by differences in X-ray response between detector channels (X-ray response non-uniformity: XRNU). XRNU is one of the systematic errors for individual channels, while it appears to be a random error for different channels. In the present study, taking advantage of the randomness, the true sensitivity for each channel has been statistically estimated. Results indicate that the dynamic range of microstrip modules (MYTHEN, Dectris, Baden-Daettwil, Switzerland), which have been assembled for a total scattering measurement system (OHGI), has been successfully restored from 104 to 106. Furthermore, the correction algorithm has been optimized to increase time efficiencies. As a result, the correcting time has been reduced from half a day to half an hour, which enables on-demand correction for XRNU according to experimental settings. High-precision X-ray total scattering measurements, which has been achieved by a high-accuracy detector system, have demonstrated valence density studies from powder and PDF studies for atomic displacement parameters.

High Precision X-ray Measurements 2021

“…X-ray spectrometers and strip detectors are the protagonist of the contributions [8,9]. In [8], ray tracing simulations are used to reproduce the Bragg spectra obtained with the VOXES von hamos spectrometer based on HAPG mosaic crystals, with particular attention to the comparison between the simulated and experimental reflection efficiencies and spectral resolutions.…”

“…In [8], ray tracing simulations are used to reproduce the Bragg spectra obtained with the VOXES von hamos spectrometer based on HAPG mosaic crystals, with particular attention to the comparison between the simulated and experimental reflection efficiencies and spectral resolutions. The strip detectors used in [8] is the MYTHEN2, produced by the Dectris company, which is also the subject of the investigations reported in [9], where the problem of X-ray response non-uniformity (XRNU) is tackled and successfully overcome with the implementation of a statistical reconstruction method.…”