Use of a ray-tracing simulation to characterize ghost rays in the FOXSI rocket experiment
Use of a ray-tracing simulation to characterize ghost rays in the FOXSI rocket experiment
复制标题
使用光线追踪模拟来表征 FOXSI 火箭实验中的幻影射线
DOI：
10.1088/1748-0221/15/11/p11032
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发表时间：
2020
影响因子：
1.3
通讯作者：
Ishikawa, S.
中科院分区：
文献类型：
--
作者：
Buitrago-Casas, J.C.;Christe, S.;Glesener, L.;Krucker, S.;Ramsey, B.;Bongiorno, S.;Kilaru, K.;Athiray, P.S.;Narukage, N.;Ishikawa, S.
与基于间接成像的技术相比，直接聚焦成像X射线提供了更高的灵敏度和更高的动态范围。聚焦光学X射线太阳成像仪(FOXSI)是一种探空型火箭有效载荷，它使用七套嵌套的Wolter-I图形镜通过直接聚焦在硬X射线中观测太阳。表征这些光学元件的性能对于优化它们的性能和了解它们的结果数据至关重要。在本文中，我们介绍了我们创建和开发的用于研究Wolter-I型X射线反射镜的光线跟踪模拟。通过对FOXSI火箭光学系统的建模，验证了光线跟踪模拟的准确性。我们发现模拟预测与光学测量的实验室数据之间有令人满意的一致性。我们使用光线跟踪模拟来描述由特定入射角度的光子产生的单反射光线(即鬼射线)的背景图案，该图案仅反射在两段Wolter-I图形中的一段上，并且仍然到达焦平面。我们使用光线跟踪模拟的结果来了解并制定一套可用于缓解鬼射线对FOXSI光学模块的影响的策略。这些策略包括在FOXSI中使用的最小的Wolter-I型反射镜的出入口处放置孔径板的优化，蜂窝型准直器的优化，以及在望远镜孔径处放置的楔形吸收镜的优化。射线跟踪模拟被证明是研究Wolter-I型X射线光学的一套可靠的工具。它可以用于许多应用，包括天体物理学、材料科学和医学成像。
Imaging X-rays by direct focusing offers greater sensitivity and a higher dynamic range compared to techniques based on indirect imaging. The Focusing Optics X-ray Solar Imager (FOXSI) is a sounding rocket payload that uses seven sets of nested Wolter-I figured mirrors to observe the Sun in hard X-rays through direct focusing. Characterizing the performance of these optics is critical to optimize their performance and to understand their resulting data. In this paper, we present a ray-tracing simulation we created and developed to study Wolter-I X-ray mirrors. We validated the accuracy of the ray-tracing simulation by modeling the FOXSI rocket optics. We found satisfactory agreements between the simulation predictions and laboratory data measured on the optics. We used the ray-tracing simulation to characterize a background pattern of singly reflected rays (ie, ghost rays) generated by photons at certain incident angles reflecting on only one of a two-segment Wolter-I figure and still reaching the focal plane. We used the results of the ray-tracing simulation to understand, and to formulate a set of strategies that can be used to mitigate, the impact of ghost rays on the FOXSI optical modules. These strategies include the optimization of aperture plates placed at the entrance and exit of the smallest Wolter-I mirror used in FOXSI, a honeycomb type collimator, and a wedge absorber placed at the telescope aperture. The ray-tracing simulation proved to be a reliable set of tools to study Wolter-I X-ray optics. It can be used in many applications, including astrophysics, material sciences, and medical imaging.