Development of compact multi-channel ultra soft X-ray spectrometer for high-accuracy particle transport measurement

使用示踪剂包裹固体颗粒(TESPEL)和电荷交换复合光谱(CXS)相结合，可以高精度地评估杂质输运系数。本研究项目的目标是研制一台紧凑型多通道超软X射线(USXR)能谱仪，这是利用高能中性束进行CXS诊断所必需的。我们采用了由一个栅准直器和一个多层反射镜组成的光学系统，以实现小型化和高通量。利用上述光学系统，我们制作了一台单道USXR光谱仪样机。在大型螺旋装置(LHD)的实验中，LHD等离子体的工作气体意外地流入了原型USXR光谱仪，导致高压MCP探测器损坏。为了解决这个问题，我们对光谱仪的设计进行了修改，并安装了带低温泵的差动泵浦系统。遗憾的是，由于对抗工作的时间比预期的要长，我们无法从改装后的光谱仪上获得实验数据。然而，我们在利用现有光谱仪研究TESPEL注入引入的示踪杂质离子的USXR发射方面取得了进展。为了利用杂质输运程序计算杂质输运系数，已开发了几个辅助计算程序。尽管多通道USXR光谱仪的开发仍有待完成，但由于其紧凑的结构，通过将这里采用的光学系统对准成扇形可以很容易地完成。

Impurity transport coefficients can be evaluated with a high degree of accuracy by using a combination of a tracer-encapsulated solid pellet (TESPEL) and a charge exchange recombination spectroscopy (CXS). The goal of this research project is the development of a compact multi-channel ultra soft X-ray (USXR) spectrometer, which is necessary for the CXS diagnostic with a high-energy neutral beam. We adopted the optical system that consists of a grid collimator and a multilayer mirror, for achieving the compactness together with the high throughput. We produced a prototype one-channel USXR spectrometer with the above optical system. During the experiment on the Large Helical Device (LHD), a working gas for LHD plasmas flowed accidentally into the prototype USXR spectrometer, and then MCP detectors with being applied a high voltage was damaged. To fix this problem, the design Of the spectrometer is modified and we proceed with the installation of differential pumping system with a cryopump. Unfortunately, since the countermeasure work takes a longer time than anticipated, we cannot obtain the experimental data from the modified spectrometer. However, we made progress in the research using existing spectrometers for studying USXR emissions from the tracer impurity ions introduced by the TESPEL injection. Several calculation codes, which are necessary secondarily for the calculation of the impurity transport coefficients using an impurity transport code, have been developed. Although the development of the multi-channel USXR spectrometer remains to be done, it can be easily done by aligning the optical system adopted here in a fan shape, owing to the compactness of that.