Jahrman Evan P, Holden William M, Ditter Alexander S, Mortensen Devon R, Seidler Gerald T, Fister Timothy T, Kozimor Stosh A, Piper Louis F J, Rana Jatinkumar, Hyatt Neil C, Stennett Martin C
Physics Department, University of Washington, Seattle, Washington 98195-1560, USA.
Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
Rev Sci Instrum. 2019 Feb;90(2):024106. doi: 10.1063/1.5049383.
X-ray absorption fine structure (XAFS) and x-ray emission spectroscopy (XES) are advanced x-ray spectroscopies that impact a wide range of disciplines. However, unlike the majority of other spectroscopic methods, XAFS and XES are accompanied by an unusual access model, wherein the dominant use of the technique is for premier research studies at world-class facilities, i.e., synchrotron x-ray light sources. In this paper, we report the design and performance of an improved XAFS and XES spectrometer based on the general conceptual design of Seidler et al. [Rev. Sci. Instrum. 85, 113906 (2014)]. New developments include reduced mechanical degrees of freedom, much-increased flux, and a wider Bragg angle range to enable extended x-ray absorption fine structure (EXAFS) measurement and analysis for the first time with this type of modern laboratory XAFS configuration. This instrument enables a new class of routine applications that are incompatible with the mission and access model of the synchrotron light sources. To illustrate this, we provide numerous examples of x-ray absorption near edge structure (XANES), EXAFS, and XES results for a variety of problems and energy ranges. Highlights include XAFS and XES measurements of battery electrode materials, EXAFS of Ni with full modeling of results to validate monochromator performance, valence-to-core XES for 3d transition metal compounds, and uranium XANES and XES for different oxidation states. Taken en masse, these results further support the growing perspective that modern laboratory-based XAFS and XES have the potential to develop a new branch of analytical chemistry.
X射线吸收精细结构（XAFS）和X射线发射光谱（XES）是先进的X射线光谱技术，对众多学科领域都有影响。然而，与大多数其他光谱方法不同的是，XAFS和XES伴随着一种不同寻常的使用模式，即该技术的主要应用是在世界级设施（即同步辐射X射线光源）上进行前沿研究。在本文中，我们报告了一种基于Seidler等人[《科学仪器评论》85, 113906 (2014)]的总体概念设计改进的XAFS和XES光谱仪的设计与性能。新进展包括减少机械自由度、大幅提高通量以及更宽的布拉格角范围，从而首次能够在这种现代实验室XAFS配置下进行扩展X射线吸收精细结构（EXAFS）测量与分析。该仪器实现了一类与同步辐射光源的任务和使用模式不兼容的新常规应用。为说明这一点，我们给出了针对各种问题和能量范围的X射线吸收近边结构（XANES）、EXAFS和XES结果的大量示例。亮点包括电池电极材料的XAFS和XES测量、对镍的EXAFS测量及对结果进行完整建模以验证单色仪性能、3d过渡金属化合物的价到芯XES、以及不同氧化态铀的XANES和XES。总体而言，这些结果进一步支持了这样一种日益增长的观点，即基于现代实验室的XAFS和XES有潜力发展成为分析化学的一个新分支。
