空间大掠入射角软X射线超反射镜的研制

The imaging detection of soft X-ray can reveal mysteries of cosmic space: evolution of stellar, formation of stars, growth of black holes, and formation of the Universe. Nested WolterⅠfocusing telescope is the most commonly used optical system in this wavelength band. In order to enhance transfer efficiency of this optical system, non-periodic multilayer with a big grazing incidence angle (supermirror) is required. Due to its application, the focal length is shortened, hence the size and weight of the telescope are reduced, and the production cost is lowered; the aperture of nested layer is enlarged, the effective collecting area is increased, and the alignment difficulty is reduced, hence imaging quality is improved..This project aims to carry out the design, fabrication and test of soft X-ray supermirrors with big grazing incidence angles based on requirements of nested WolterⅠoptical system. The selected material pairs include Ir/B4C, W/Si, Pt/C, etc. The biggest grazing incidence angle is 1.7 degree, the wavelength range is from 0.1 to 10keV. The supermirror has a low stress, little property variance of optical surface, and a stable structure. As compared to two layers, it has a more than 50% of higher reflectivity in high energy band, as well as high reflectivity in low energy band. The successful development of this project will lay a solid foundation for the research of focusing X-ray telescope of our country.

通过对软X射线波段的成像探测研究，可以揭示宇宙空间的奥秘：如恒星的演化，星体的形成，黑洞的长大，宇宙的形成等。嵌套WolterⅠ型聚焦望远镜是这个波段最常用的光学系统，为了提高此光学系统的传输效率，需要使用大掠入射角非周期多层膜（超反射镜）。它能够缩短焦距，进而减小望远镜的尺寸和重量，降低制造成本;增大嵌套层口径，提高有效集光面积，降低装调难度，进而提高成像质量。.本项目是基于嵌套WolterⅠ光学系统的需要，设计和制备大掠入射角软X射线超反射镜，并探索它的反射率测试方法。拟使用的材料对包括Ir/B4C、W/Si和Pt/C等。最大掠入射角1.7°，波长范围0.1-10keV。该多层膜应力低，镀制前后光学表面特性变化小，结构稳定。在高能量波段，它比两层膜的反射率提高了50%以上，而在低能量波段保持了反射率高的特点。.本项目的成功研制，将为我国X射线聚焦天文望远镜的研制奠定坚实的基础。

通过对软X射线波段的成像探测研究，可以揭示宇宙空间的奥秘：如恒星的演化，星体的形成，黑洞的长大，宇宙的形成等。嵌套WolterⅠ型聚焦望远镜是这个波段最常用的光学系统，为了提高此光学系统的传输效率，需要使用大掠入射角非周期多层膜（超反射镜）。它能够缩短焦距，进而减小望远镜的尺寸和重量，降低制造成本;增大嵌套层口径，提高有效集光面积，降低装调难度，进而提高成像质量。.本项目是基于嵌套WolterⅠ光学系统的需要，设计和制备大掠入射角软X射线超反射镜，并探索它的反射率测试方法。.摸索出了目标反射率修正法、针式算法和Block法来设计W/Si、Ir/SiC和Pt/C三种超反射镜。掠入射角为1.0°，1.4°，1.7°。在国际上，我们是首次使用针式算法来设计这么复杂的掠入射X射线超反射镜，并取得了较好的效果。.制备出W/Si、Ir/SiC和Pt/C三种超反射镜，Pt/C超反射镜具有最好的性能。它在5-10 keV 波段的平均反射率分别为18.19% （1.0°）, 9.39% （1.4°）, 4.87% （1.7°），是Ir/SiC两层膜的3倍（1.0°），18倍（1.4°）和32倍（1.7°），表现出了极大的优越性。它还具有良好的角度容忍性：1.0°Pt/C超反射镜在1.5°时仍具有大于10%的反射率；1.4°Pt/C超反射镜在1.9°时仍具有8%的反射率；1.7°Pt/C超反射镜在2.2°时仍具有大于5%的反射率。这给后续的光机装调提供了很大的便利。.本项目的研究成果有望应用到未来我国将要研制的X射线天文望远镜上。本项目的成功研制，将为我国X射线聚焦天文望远镜的研制奠定坚实的基础。