红外与激光工程, 2017, 46(7): 0718002, 网络出版: 2017-07-01

基于多元约束的小型软X射线偏振望远镜光学设计及优化

Optical design and optimization of the small-scale soft X-ray polarization telescope based on multi-constraints
作者单位

1同济大学 先进微结构材料教育部重点实验室, 上海 200092

2同济大学 物理科学与工程学院 精密光学工程技术研究所, 上海 200092

摘要
作为揭示物质在强磁场、强引力场中的行为方式以及天体辐射偏振产生原因的重要手段, X射线偏振探测在近40年来一直是高能天体物理的研究热点。小型软X射线天文偏振探测望远镜采用抛物面聚焦方式将X射线会聚至探测器处, 通过在反射镜表面镀制多层膜实现高反射率和能量分辨。文中对小型天文偏振望远镜抛物面的两种空间布局方式, 即中心环绕旋转式镜面布局和交叉对称式镜面布局进行了理论分析, 构建了综合集光面积和制作难度的优化模型, 基于多元约束方式进行了参数优化。结果显示, 在系统口径受限、探测器有一定尺寸的实际应用环境中, 参数优化后的交叉对称式镜面布局方案较常规中心环绕式设计更有优势, 既能获得较大的集光面积, 又能兼顾镜面加工的可行性。
Abstract
The probe of the X-ray polarization in high-energy astrophysics has been a research focus over the past 40 years, and it has been an efficient way to reveal matters′ behaviors under circumstances of extreme magnetic and gravitational fields, and to understand the causation of polarization. The small-scale soft X-ray polarization telescope usually focus soft X-ray into the detection zone, and the surface type of the telescope is paraboloid. The mirror of the telescope is deposed with multilayer, it can reflect soft X-ray with a rather high reflectivity and a high energy resolution, which satisfies the Bragg condition. Here, two kinds of design configurations for a soft X-ray polarimetry mission based on paraboloidal surface shape were presented. Some calculations and analyses were done under the limitation of a specific size of the whole system. The relation was summarized between collected area, the complexity of the fabrication, and other practical application factors. The result of the optimization demonstrates that the optimized choice for the design can guarantee the practical utilization in reality.
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