采用白光X射线源和模拟阵列能量色散阵列探测器的高通量粉末衍射技术

工程（英文） ›› 2022, Vol. 10 ›› Issue (3) : 81 -88. DOI: 10.1016/j.eng.2021.05.023

研究论文

汪晓平 ^a ,
董伟伟 ^b ,
张鹏 ^c ,
唐浩琪 ^e ,
张澜庭 ^a ,
杨铁莹 ^e ,
刘鹏 ^b ,
汪洪 ^a ,
项晓东 ^c^,^d^,^f^,^g

作者信息 +

High-Throughput Powder Diffraction Using White X-Ray Beam and a Simulated Energy-Dispersive Array Detector

Xiaoping Wang ^a ,
Weiwei Dong ^b ,
Peng Zhang ^c ,
Haoqi Tang ^e ,
Lanting Zhang ^a ,
Tieying Yang ^e ,
Peng Liu ^b ,
Hong Wang ^a ,
X.-D. Xiang ^c^,^d^,^f^,^g

Author information +

文章历史 +

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摘要

在上海同步辐射光源（SSRF）的弯铁光束线上，利用由空间扫描硅漂移探测器（SDD）模拟获得的能量色散阵列探测器，对CeO₂样品进行高通量白光X射线粉末衍射（pXRD）实验。考虑到与实验硬件和衍射角相关的多种因素，对数据进行了详细分析和校正。校正后的衍射图谱表明，由能量色散X 射线衍射（EDXRD）获得的不同衍射峰之间的相对强度与来自角度分辨X射线衍射（ARXRD）的相对强度一致，说明EDXRD结果可用于分析未知样品的晶体结构。实验同时采集了X射线荧光（XRF）信号。来自所有像素的XRF计数可直接在能量坐标下叠加，而衍射信号则需在d 空间下叠加，从而大大改善了阵列探测器的峰值强度和信噪比（S/N）。与ARXRD相比，白光X射线衍射信号强度是单色光衍射信号强度的10⁴倍左右。q 空间中衍射峰的半峰全宽（FWHM）取决于探测器的能量分辨率、探测器接收角范围和衍射角大小。如果实验参数选择得当，在当前能量色散探测器的能量分辨率下，EDXRD有可能实现与ARXRD相同甚至更小的半峰全宽。

Abstract

High-throughput powder X-ray diffraction (XRD) with white X-ray beam and an energy-dispersive detector array are 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.