Development of high-wavelengh-resolution XUV multilayr

本课题的研究目的是研制高性能的x射线多层反射镜和x射线CCD相机，这是x射线望远镜的主要组成部分。多层反射镜由多层高z（原子序数）和低z材料组成，反射波长满足布拉格条件的正入射x射线。要诊断温度为1- 20mk的宇宙等离子体，需要系统波长分辨率高达30-50的多层反射镜。实现这种高波长分辨率的方法是增加对反射率有贡献的层对数，即减少反射器和间隔器的吸收材料，并减小反射器的厚度。我们制备了两种类型的多层反射镜(含铝间隔层的碳化硅反射镜（层周期厚度为20%）和含硅间隔层的MoSi反射镜（层周期厚度为25%），得到λ /DELTA λ - 25-30，峰值反射率为13-20%。该波长分辨率接近于数值模拟得到的值，并且大大高于传统Mo/Si多层材料得到的值。我们还开发了多波器顶部的波阱，可以在304ALPHA处捕获强烈的HeII线。在所需波长（本例中为211A）和304A处的反射率之比达到100，这使得我们可以在所需波长处进行无污染观测。我们还测量了背照ccd的量子效率。

The purpose of this research project is to develop a high performance X-ray multilayr mirror and an X-ray CCD camera, which are primary components of an X-ray telescope. A multilayr mirror consists of multiple layrs of High-Z (atomic number) and low-Z materials, and reflects normal-incidence X-rays with wavelength satisfying the Bragg condition.Multilayr mirror with system wavelength resolution lambda/DELTA lambda as high as 30-50 is required for the diagnostics of the cosmic plasma with temperature 1-20 MK.Such a high wavelength resolution was realized by increasing the number of the layr pairs contributing to the reflectance, i.e. by selecting less absorbing materials for both the reflector and the spacer and by decreasing thickness of the reflector. We fabricated two types of the multilayr mirrors (silicon carbide reflector (20% thickness of the layr period) with aluminum spacer, MoSi reflector (25% thickness) with silicon spacer) and found lambda/DELTA lambda - 25-30, and the peak reflectivity 13-20%. This wavelength resolution is close to the value obtained with the numerical simulation, and is considerably higher than the value obtained with the conventional Mo/Si multilayr.We have also developed the wave-trap on top of the multilater that traps the intense HeII line at 304ALPHA. The ratio of the reflectivity at the desired wavelength (211A in this case) and at 304A reaches 100, which allows us to make contamination-free observations at the desired wavelength. We have also measured the quantum efficiency of the back-illuminated CCDs.