Wolter型X射线嵌套望远镜成像质量分析

Image Quality Evaluation of Wolter X-Ray Nested Telescope

X 射线成像技术在空间探测中的应用日渐广泛，为了提高孔径利用率和系统有效面积，通常采用Wolter-Ⅰ型嵌套望远镜对空间X 射线源进行会聚成像。由于传统的光学设计软件在分析掠入射系统方面存在一定的缺陷，因此使用MT_RAYOR 工具库自编程对X 射线望远镜进行成像质量分析。MT_RAYOR 用于Wolter-Ⅰ型嵌套结构望远镜系统的分析，具有全面、准确和快捷的优势。基于MT_RAYOR，对用于0.2-20 keV 波段成像的嵌套型双锥结构望远镜进行了系统设计，从有效面积、点扩展函数、能量集中度等方面进行了成像质量分析。该结构在10 keV 以内保持500 cm2 以上的稳定有效面积，在硬X 射线波段的有效面积也可达到250 cm2 以上，系统工作波段跨度大、稳定性高。分析了辐条和反射面的面形误差对系统在实验中成像质量的影响，对望远镜系统的优化和装调具有指导作用。

X-ray imaging technology has developed fast in spatial explorations. In order to obtain higher throughput and larger effective area, Wolter-Ⅰnested telescope structure is usually adopted to focus and image the spatial Xray sources. Traditional optical analysis software is imperfect in the analysis of grazing incident system. Therefore, programs are written using the MT_RAYOR tools to evaluate the image quality of Wolter X-ray nested telescope. MT_RAYOR has an advantage of being general, accurate, convenient and fast in predicting grazing incident Wolter- Ⅰnested structures. Based on MT_RAYOR, the structure parameters of nested conical telescope working at 0.2- 20 keV are designed, and detailed image quality analysis are presented, including the effective area, point spread function, and encircled energy function. The system can achieve a stable effective area of about 500 cm2 at 0.2-10 keV, and the effective area keeps above 250 cm2 in hard X-ray region, thus, the system has a wide range of working wavelength and good stability. Furthermore, the spokes and surface deformation profile are taken into consideration in order to evaluate the effects on image quality. The results have directive significance to optimization and assembling of the telescope system.