Mo/Si多层膜在质子辐照下反射率的变化

为了检验应用在极紫外波段空间太阳望远镜上Mo/Si多层膜反射镜在空间辐射环境下反射率的变化情况, 模拟了部分空间太阳望远镜运行轨道的辐射环境, 利用不同能量和剂量的质子对Mo/Si多层膜反射镜进行辐照实验.辐照前后反射率测量结果显示，由于带电粒子的辐照损伤，质子辐照会使Mo/Si多层膜反射镜的反射率降低，且质子能量越低、剂量越大，对多层膜的反射率影响越明显. 当质子能量E=160keV，剂量＝6×10¹¹/mm²时，反射率降低4.1%；能量E=100keV，剂量=6×10¹¹/mm²时, 反射率降低5.7%；能量E=50keV，剂量=8×10¹²/mm²时，反射率降低10.4%. 用原子力显微镜测量辐照后Mo/Si多层膜反射镜的表面粗糙度比辐照前明显增加，致使散射光线能量逐渐增大并最终导致反射率的降低. 关键词：质子辐照Mo/Si多层膜反射镜辐照损伤

Change of reflectivity of Mo/Si multilayer irradiated by proton

In this paper, we simulated part of the low-Earth orbits space radiation environment to investigate its influence on the reflectivity change of Mo/Si multilayer mirror used in the space solar telescope. The reflectivity was investigated before and after irradiation with proton of different energies and fluences. The results show that the reflectivity decreases when irradiated by proton because of the radiation-induced damage in the multilayer mirror, and it drops more when the energy of the proton decreases while their fluence increases. When the energy of proton E=160keV with fluence　=6×10¹¹/mm²，E=100keV with fluence　=6×10¹¹/mm² and E=50keV with fluence =8×10¹²/mm²，the reflectivity drops about 4.1%, 5.7% and 10.4%， respectively. The roughness measured by atomic force microscopy increases after irradiation, which results in more scattering of incident ray so that the reflectivity of multilayer is reduced.