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Development of high-wavelengh-resolution XUV multilayr

高波长分辨率XUV多层膜的开发

基本信息

批准号：
07454037
负责人：
TSUNETA Saku
金额：
$ 3.84万
依托单位：
National Astronomical Observatory (1996)The University of Tokyo (1995)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07454037/
关键词：
X-ray multilayr XUV multilayr X-ray mirror X-ray telescope dispersion optics CCD X-ray CCD XUV anti-reflection coating 多層膜 X線光学

项目摘要

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.

本研究项目的目的是开发一种高性能的X射线多层镜和X射线CCD相机，这是X射线望远镜的主要部件。多层反射镜由高原子序数和低原子序数的多层材料组成，反射波长满足布拉格条件的正入射X射线。诊断温度为1-20MK的宇宙等离子体需要具有高达30-50的系统波长分辨率的多层反射镜。这种高波长分辨率是通过增加对反射率有贡献的层对的数量来实现的，即为反射器和间隔器选择较少的吸收材料，通过减少反射器的厚度来实现这种高波长分辨率。我们制作了两种类型的多层膜反射镜(碳化硅反射镜(厚度为膜层厚度的20%)和MoSi反射镜(厚度为25%)的硅垫层)，其峰值反射率为13-20%。这一波长分辨率接近数值模拟的结果，也大大高于传统的Mo/Si多层膜的结果。我们还在多层膜的基础上发展了一种捕获304ALPHA强HeII线的波陷器。在所需波长(本例中为211A)和304A处的反射率之比达到100，这使我们能够在所需波长进行无污染观测。我们还测量了背向照明的CCDs的量子效率。