Development of curved crystal spectrometer for soft X-ray emission spectroscopy

软X射线共振发射光谱是研究固体电子结构信息的有力手段之一。同步辐射由双晶单色仪选择。用二次单色仪分析了样品的二次X射线发射光谱(荧光光谱)。然而，二次辐射的强度普遍较弱，因此我们研制了新型的高分辨率、高效率的光谱仪。为了实现高效率，我们研制了配备位置灵敏探测器的弯曲晶体光谱仪，并设计了新型软X射线光谱仪。该光谱仪是约翰型弯曲晶体真空谱仪，其中安装了一个曲率半径为100 cm的弯曲晶体。原子平面与面平行的分析晶体被放置在与罗兰圆相对应的圆的切线上。位置灵敏探测器与该圆相切放置，利用硅靶的SiK_α发射光谱对该光谱仪进行了测试。在这种情况下，使用来自电子枪的电子束(3KV，80μA)作为激发源。该光谱仪对SiK_α区的分辨率约为0.5 eV。测试了三种类型的探测器：微通道板、阻性阳极气体正比计数器和步进式位置灵敏探测器。

Soft X-ray resonant emission spectroscopy is one of powerful methods to study the information about the electronic structure of solids. The synchrotron radiation is selected by the double crystal monochrometor. The secondary X-ray emission spectra(fluorescence spectra)from sample are analyzed by the secondary monochrometor. However, the intensity of the secondary radiation is generally weak, then we developed the new high resolution, high efficiency spectrometer. In order to achieve high efficiency, we developed the bent crystal spectrometer equipped with the position sensitive detector.We designed the new soft X-ray spectrometer. The spectrometer is the bent crystal vacuum spectrometer of Johann type, in which a bent crystal of radius of curvature 100cm is mounted. The analyzing crystal with its atomic planes parallel to the face is placed tangent to a circle corresponding to the Rowland circle. The position sensitive detector is placed tangent to this circle.The test measurement of this spectrometer was performed by using Si K_α emission spectra from Silicon target. In this case, the electron beam(3KV, 80μA)from electron gun was used for excitation source. The resolution of the spectrometer was estimated about 0.5 eV for Si K_α region. Three type detectors, microchannel plate, resistive anode gas proportional counter and backgammon type position sensitive detector have been tested.