A new crystal spectrometer for application in X-ray opacity experiments is proposed. The conditions necessary to yield broad spectral coverage with a resolution ${>}$500, strong rejection of hard X-ray backgrounds and negligible source broadening for extended sources are formulated. In addition, the design, response modeling and reporting of an elliptical crystal spectrometer in conjunction with a linear detector are presented. The measured results demonstrate the performance of the new crystal spectrometer with a broad energy coverage range, high spectral resolution, and high luminosity (good collection efficiency). This spectrometer can be used in combination with point-projection backlighting techniques as utilized in X-ray opacity experiments. Specifically, the X-ray source, transmission and self-emission spectra of the sample can be measured simultaneously in a single shot, which can reduce the experimental uncertainties from shot-to-shot fluctuations. The new crystal spectrometer has been used in the X-ray opacity experiment to precisely measure the aluminum $K$-absorption edge shift in the energy range around 1.560 keV in strongly compressed matter. It is demonstrated that the spectrometer can be used to realize measurements of new and unpredictable physical interactions of interest, as well as basic and applied high-energy-density science.

中文翻译：

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用于 SGII X 射线不透明度实验的椭圆晶体光谱仪的性能

提出了一种用于X射线不透明度实验的新型晶体光谱仪。产生具有分辨率的宽光谱覆盖范围所必需的条件${>}$500，对硬 X 射线背景的强抑制和扩展源的源展宽可忽略不计。此外，还介绍了椭圆晶体光谱仪与线性检测器的设计、响应建模和报告。实测结果证明了新型晶体光谱仪具有宽能量覆盖范围、高光谱分辨率和高光度（收集效率好）的性能。该光谱仪可以与 X 射线不透明度实验中使用的点投影背光技术结合使用。具体来说，样品的 X 射线源、透射和自发射光谱可以在单次拍摄中同时测量，这可以减少每次拍摄波动的实验不确定性。$K$-在强压缩物质中，能量范围在 1.560 keV 附近的吸收边缘偏移。证明该光谱仪可用于实现对新的和不可预测的感兴趣的物理相互作用的测量，以及基础和应用的高能量密度科学。