X-ray calorimeters routinely achieve very high spectral resolution, typically a few eV full width at half maximum (FWHM). Measurements of calorimeter line shapes are usually dominated by the natural linewidth of most laboratory calibration sources. This compounds the data acquisition time necessary to statistically sample the instrumental line broadening and can add systematic uncertainty if the intrinsic line shape of the source is not well known. To address these issues, we have built a simple, compact monochromatic x-ray source using channel cut crystals. A commercial x-ray tube illuminates a pair of channel cut crystals that are aligned in a dispersive configuration to select the Kα1 line of the x-ray tube anode material. The entire device, including the x-ray tube, can be easily hand-carried by one person and may be positioned manually or using a mechanical translation stage. The output monochromatic beam provides a collimated image of the anode spot with magnification of unity in the dispersion direction (typically 100 μm-200 μm for the x-ray tubes used here) and is unfocused in the cross-dispersion direction so that the source image in the detector plane appears as a line. We measured output count rates as high as 10 count/s/pixel for the Hitomi soft x-ray spectrometer, which had 819 μm square pixels. We implemented different monochromator designs for energies of 5.4 keV (one design) and 8.0 keV (two designs), which have effective theoretical FWHM energy resolution of 0.125 eV, 0.197 eV, and 0.086 eV, respectively; these are well-suited for optimal calibration measurements of state-of-the art x-ray calorimeters. We measured an upper limit for the energy resolution of our Cr Kα1 monochromator of 0.7 eV FWHM at 5.4 keV, consistent with the theoretical prediction of 0.125 eV.

中文翻译：

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简单、紧凑、高分辨率的单色 X 射线源，用于表征 X 射线热量计阵列

X 射线量热仪通常可实现非常高的光谱分辨率，通常为几个 eV 的半峰全宽 (FWHM)。量热仪线形的测量通常由大多数实验室校准源的自然线宽决定。这增加了对仪器谱线展宽进行统计采样所需的数据采集时间，并且如果源的固有谱线形状不为人所知，则会增加系统不确定性。为了解决这些问题，我们使用通道切割晶体构建了一个简单、紧凑的单色 X 射线源。商用 X 射线管照亮一对以色散配置排列的通道切割晶体，以选择 X 射线管阳极材料的 Kα1 线。整个设备，包括 X 射线管，可以由一个人轻松携带，并且可以手动或使用机械平移台定位。输出单色光束提供阳极点的准直图像，在色散方向上具有统一的放大倍数（此处使用的 X 射线管通常为 100 μm-200 μm），并且在交叉色散方向上未聚焦，因此源图像在探测器平面中显示为一条线。我们为 Hitomi 软 X 射线光谱仪测量了高达 10 次/秒/像素的输出计数率，其具有 819 平方微米的像素。我们针对 5.4 keV（一种设计）和 8.0 keV（两种设计）的能量实现了不同的单色器设计，它们的有效理论 FWHM 能量分辨率分别为 0.125 eV、0.197 eV 和 0.086 eV；这些非常适合最先进的 X 射线热量计的最佳校准测量。我们在 5.4 keV 下测量了 0.7 eV FWHM 的 Cr Kα1 单色器的能量分辨率上限，与 0.125 eV 的理论预测一致。