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器选择。利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，二次辐射的强度一般较弱，于是我们研制了新型的高分辨率、高效率的光谱仪。为了实现高效率的软X射线谱仪，我们研制了一种采用位置灵敏探测器的弯晶谱仪。谱仪为Johann型弯晶真空谱仪，其中安装了曲率半径为100厘米的弯晶。将其原子平面平行于表面的分析晶体与对应于罗兰圆的圆相切放置。位置灵敏探测器与该圆相切，用硅靶的Si K_α发射谱对该谱仪进行了测试。在这种情况下，来自电子枪的电子束（3KV，80μA）被用作激发源。谱仪对Si K_α区的分辨率估计为0.5eV。对微通道板、电阻阳极气体正比计数管和双陆棋型位置灵敏探测器三种探测器进行了测试。

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.