托卡马克弯晶谱仪双晶体结构应用的初步研究

Preliminary study on double-crystal for X-ray curved-crystal spectrometer on EAST

X射线弯晶谱仪作为托卡马克装置等离子体温度和旋转速度等参数诊断测量的重要手段之一,通常利用单晶体衍射分光来测量某种特定杂质的特征谱,这也限制了弯晶谱仪所能测量的等离子体温度范围。为解决更高温度等离子体测量问题,有效提高目前弯晶谱仪诊断系统温度测量范围,用双晶体代替原有单晶体,通过选择合适的晶体和Bragg衍射角组合,利用同一个探测器同时测量类氢和类氦的氩离子光谱,实现更高更宽温度范围测量。本文就东方超环(Experimental Advanced Superconducting Tokamak,EAST)弯晶谱仪双晶体应用方面的设计和技术实现进行了阐述,并首次在EAST装置上成功实现了氩离子类氦和类氢谱线的测量,利用类氦线和类氢线拟合得到的氩离子温度非常接近,验证了双晶体结构的可行性。

Background：X-ray curved-crystal spectrometer, as one of important diagnostic tool for measuring the plasma temperature and rotation velocity of the tokamak, is usually based on the satellite spectra of some special kind of impurity by single-crystal diffraction, which limits the temperature range to be measured simultaneously.Purpose： This study aims to effectively broaden the temperature range of the spectrometers, an assembly of double-crystal was designed to replace the previous of single-crystal.Methods： The two crystals of the assembly having the similar Bragg angles were installed on the same pedestal, which could make the spectra recorded on the same detector. Consideration and technology route of the double-crystal were described and analyzed together with the experimental tests on the Experimental Advanced Superconducting Tokamak （EAST）.Results： Experimental results on the double-crystal X-ray spectrometer showed that the He-like and H-like Ar spectra were obtained for the first time, and the ion Ar temperatures calculated by two kinds of spectra were in good consistence within a certain error range. Conclusion：The application of double-crystal for X-ray curved-crystal spectrometers on EAST proposed in this paper is applicable and feasible.