Spherically‐bent crystal analyzers (SBCAs) see considerable use in very high‐resolution hard X‐ray wavelength dispersive X‐ray fluorescence spectroscopy, often called X‐ray emission spectroscopy (XES). While Si and Ge are the most frequently used diffractive components of SBCAs, we consider here the somewhat classical choice of muscovite mica as the dispersing element. We find that the various harmonics of a highest‐quality mica‐based SBCA show ~5–~40% of the integral reflectivity per unit solid angle of a typical Si or Ge SBCA in the hard X‐ray range, and that the mica SBCA have comparable energy resolution to the traditional SBCAs. Interestingly, the choice of mica comes with a practical benefit: the primary (0,0,2) reflection has sufficiently strong harmonics that are fairly tightly spaced in energy so that they span the complete energy range from ~4 to ~11 keV when used at convenient Bragg angles in a Rowland circle spectrometer. Hence, a single mica SBCA can be used for every K‐shell emission line of three dimensional transition metals and every L‐shell emission line of the lanthanide elements simply by selecting the correct mica (0,0,2) harmonic with a final energy‐dispersive solid state detector. The loss in efficiency is counteracted by an operational efficiency, i.e., the “universal” application of a single analyzer over a very large range of elements. This performance suggests future application of mica SBCAs in both laboratory‐based XES and synchrotron‐based photon‐in, photon‐out spectroscopies in the hard X‐ray range.

中文翻译：

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球形弯曲云母分析仪作为X射线光谱学的通用分散元件

球形弯曲晶体分析仪（SBCA）在非常高分辨率的硬X射线波长色散X射线荧光光谱法中被大量使用，通常称为X射线发射光谱法（XES）。尽管Si和Ge是SBCAs的最常用衍射组分，但在这里我们认为白云母云母作为分散元素是比较经典的选择。我们发现，最高质量的基于云母的SBCA的各种谐波显示出在硬X射线范围内典型Si或Ge SBCA的每单位立体角的积分反射率的〜5–〜40％，并且云母SBCA具有与传统SBCA相当的能量分辨率。有趣的是，选择云母会带来实际好处：主要（0,0，2）反射具有足够强的谐波，其谐波在能量上的分布非常紧密，因此当它们在Rowland圆光谱仪中以方便的布拉格角使用时，它们跨越的能量范围从〜4到〜11 keV。因此，只需选择正确的具有最终能量的云母（0,0,2）谐波，就可以将单个云母SBCA用于三维过渡金属的每条K壳发射线和镧系元素的每条L壳发射线分散型固态检测器。效率上的损失可以通过操作效率来抵消，例如，单个分析仪在众多元件上的“通用”应用。这一性能表明云母SBCA将来在硬X射线范围内的实验室XES和基于同步加速器的光子输入，光子输出光谱学中都将得到应用。