Engineering (Mar 2022)
High-Throughput Powder Diffraction Using White X-Ray Beam and a Simulated Energy-Dispersive Array Detector
Abstract
High-throughput powder X-ray diffraction (XRD) with white X-ray beam and an energy-dispersive detector array is demonstrated in this work on a CeO2 powder sample on a bending magnet synchrotron beamline at the Shanghai Synchrotron Radiation Facility (SSRF), using a simulated energy-dispersive array detector consisting of a spatially scanning silicon-drift detector (SDD). Careful analysis and corrections are applied to account for various experimental hardware-related and diffraction angle-related factors. The resulting diffraction patterns show that the relative strength between different diffraction peaks from energy-dispersive XRD (EDXRD) spectra is consistent with that from angle-resolved XRD (ARXRD), which is necessary for analyzing crystal structures for unknown samples. The X-ray fluorescence (XRF) signal is collected simultaneously. XRF counts from all pixels are integrated directly by energy, while the diffraction spectra are integrated by d-spacing, resulting in a much improved peak strength and signal-to-noise (S/N) ratio for the array detector. In comparison with ARXRD, the diffraction signal generated by a white X-ray beam over monochromic light under the experimental conditions is about 104 times higher. The full width at half maximum (FWHM) of the peaks in q-space is found to be dependent on the energy resolution of the detector, the angle span of the detector, and the diffraction angle. It is possible for EDXRD to achieve the same or even smaller FWHM as ARXRD under the energy resolution of the current detector if the experimental parameters are properly chosen.
