Stability Study Of Mo/Si Multilayer And Ge Film In Space Environment

Space weather has a great influence on the human production, survival, space and military activities. Therefore, the space weather monitoring which used in scientific research and application has been gradually established. The observation of the earth’s plasmasphere is the major means to observe the near-earth space environment, it can be used to study the interactions of the earth’s ionosphere, magnetosphere and the solar wind. The extreme ultraviolet camera is installed on the lander of Chang’E 3 to observe the earth’s plasmasphere. Space environment on the lunar surface has a high vacuum, large temperature difference, strong particles irradiation, which have a great effect on the performance of Mo/Si multilayers and Ge film. In order to prepare an enduring and high stability Mo/Si multilayers and Ge film, we study the films from the following four aspects: thermal stability, stress stability, radiation stability and time stability, to provide theoretical and experimental basis for the engineering application of the high stability Mo/Si multilayers and Ge film. The research contents are as followings:To ensure the stability of the optical and electrical properties of Mo/Si multilayer in lunar surface temperature environment, we use the in-situ and ex-situ ways to analyse the thermal stability. In the in-situ test way, the structure of Mo/Si multilayers is stable in the temperature range from-135 °C to 300 °C, which indicates can work normally in the lunar surface temperature environment. The Ge film resistance ranges from 520 MΩ/□ to 124 MΩ/□ when the temperature ranges from-20 °C to +80 °C, which ensures the high imaging performance of the detector.To verify the stress stability of the Mo/Si multilayer and Ge film, we use the in-situ and ex-situ ways to study the stress variation. The stress of the Mo/Si multilayer mirror we prepared in ex-situ annealing way is only-26 Mpa. In the in-situ stress research, the surface shape of the Mo/Si multilayer mirror in the lunar temperature environment, and the stress of them are calculated by the change of surface shape. The results demonstate that the low temperature in lunar surface has no effect on the film stress, and the high temperature in lunar surface relaxes the film stress.To assess the influence of the irradiation on the performance of Mo/Si multilayer and Ge film, the Monte-Carlo method is used to simulate the concentration distributions of the defects in films after radiation of protons with energy of 10 ke V, 50 ke V, 100 ke V. The experimental result is in agreement with the simulation of Monte-Carlo method. The experimental results show that the higher the proton energy is, the deeper the damage to the film will be.To solve the resistance increasing problem caused by the oxidation in atmospheric environment, oxidation characteristics and time stability of Ge film are studied comprehensively. And the performance of the Ge film with radio frequency and direct current methods is comparatively analyzed, the results show that the Ge film prepared by direct current method is more stable, and the environmental adaptability is higher.