High-throughput Powder Diffraction Using White X-ray and Simulated Energy Dispersive Array Detector

Hong Wang^1*,Xiaoping Wang¹, Weiwei Dong², Haoqi Tang³, Peng Zhang³, Lanting Zhang¹, Tieying Yang⁴, Peng Liu^2*, X.-D. Xiang^3*

¹Materials Genome Initiative Center and School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

           ²Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China      

³Department of Materials Science and Engineering,Southern University of Science and Technology, Shenzhen 518055, China

⁴Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China

ABSTRACT: High-throughput powder X-ray diffraction (XRD) with white X-ray and an energy dispersive detector array are demonstrated on a CeO2 powder sample on a bending magnet synchrotron beamline at 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 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 (ADXRD), which is necessary for analyzing crystal structures for unknown samples. The X-ray fluorescent (XRF) signal is collected simultaneously. XRF counts from all pixels are integrated directly per energy, while the diffraction spectra in q-space, resulting in much improved peak strength and signal-to-noise ratio for the array detector. Comparing with ADXRD, the diffraction signal generated by white X-ray beam over monochromic light under the experimental condition is about 104 times higher. The FWHM of the peaks in q-space was 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 ADXRD under the energy resolution of the current detector if the experimental parameter is properly chosen.

Fig. 1: Schematics of (a) angle-resolved X-ray diffraction with single-point detector scanner (ADXRD) and 2D detector array (2D-ADXRD); (b) energy dispersive X-ray diffraction with single-point ED detector (EDXRD) and 2D ED detector array (2D-EDXRD).

Keywords: High throughput experiment, White beam X-ray diffraction, Energy dispersive array detector, EDXRD, ADXRD