Application of Multilayer Reflectors to Spectroscopic and Instruments for Cosmic X-Ray Observation

多层膜反射器的发展使之有可能应用于掠入射和垂直入射的X射线光学系统，以便在0.1-10keV范围内进行连续的X射线观测。对于掠入射X射线望远镜，在固定的几何构型下，多层膜反射器具有使掠射角更大、能量范围扩大到10keV的优点。正入射X射线望远镜在0.4keV以下的能量范围内是可以获得的，尽管敏感的能级受到由层厚度和层对数估计的布拉格条件的限制。多层膜也是制作X射线能谱仪和偏振器的有用光学元件。我们正在用电子束蒸发的方法在超高真空中制作多层反射镜。材料组合为Mo/C、Mo/Si和Ni/C，层对数为5~20对，层厚为36~100A。它们被沉积在表面粗糙度为2-3A(RMS)的浮法玻璃和超抛光玻璃的平面和图形衬底上。通过测量反射率、波长分辨率和反射级的Bragg角来评价所制备的多层膜的反射率、波长分辨率和布拉格角。对14-250A波段的单色化同步辐射在高能物理国家实验室的光子工厂和分子科学研究所的UVSOR进行了进一步的研究。在掠入射时，Mo/C的峰值反射率为80%，而在近正入射时，Mo/Si的峰值反射率大于30%。

Development of multilayer reflectors makes it possible to apply to the grazing and normal incidence X-ray optic system for the comsic X-ray observation in 0.1 - 10keV region. For the grazing incidence X-ray telescope, multilayer reflectors have an advantage to make larger the glancing angle and to extend the energy range up to 10keV in the fixed geometrical configuration. The normal incidence X-ray telescope is attainable in the energy range below 0.4keV, though the sensitive energy hand is limited by Bragg condition estimated form the layer thickness and the number of layer pairs. Multilayers are also useful optical elements to fabricate the X-ray spectrometer and polarimeter.We are fabricating multilayer reflectors with an electro beam evaporation in method ultrahigh vacuum. Material combinations are Mo/C, Mo/Si and Ni/C with 5-20 layer pairs and the layer thickness of 36-100A. They are deposited on flat and figured substrates of float glass and superpolished glass with the surface roughness of 2-3A(rms).Multilayers thus fabricated are evaluated by measuring the reflectivity, the wavelength resolution and the Bragg angle of the reflection order with four characteristic X-rays of Cu-K<alpha>(1.54A), Si-K<alpha> (7.13A), Al-K<alpha>(8.34A), C-K<alpha>(44.7A). Further investigations are carried out with the monochromatized synchrotron radiation in 14-250A band at Photon Factory, National Laboratory for High Energy Physics, and at UVSOR, Institute for Molecular Science. The peak reflectivity of Cu-K<alpha> is obtained to be 80% for Mo/C in the grazing incidence and that of <lambda>160A to be more than 30% for Mo/Si in the near normal incidence.