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据范德比耳特大学的M. H. Mendenhall等人报导,空间中迁到的高能粒子可能使氟化镁镀层破坏。他们发现,真空中每一250keVa粒子平均可从MgF_2镀层表面去除2.2个氟原子,从而使镀层反射率逐渐减小。最后结果是镀层表面反射率发生“致命性”变化,MgF_2变成金属镁。MgF_2镀层一直用于空间光学系统,包括受到某些高能粒子照射的哈勃空间望远镜。哈勃的设计可能使主镜不受高粒子通量的影响,但Mendenhall等告诫说,将受真空中(即在空间)a粒子(可能还有中子)辐照的镀层,应避免采用。
According to M. H. Mendenhall et al. At Vanderbilt University, the migration of energetic particles in space may destroy the magnesium fluoride coating. They found that, on average, each 250 keVa particle in the vacuum removes 2.2 fluorine atoms from the surface of the MgF 2 coating, thereby decreasing the reflectivity of the coating. The end result is a “fatal” change in reflectivity on the surface of the coating, with MgF 2 becoming metallic magnesium. MgF 2 coatings have been used in space optical systems, including the Hubble Space Telescope, which is exposed to certain energetic particles. Hubble’s design may keep the primary mirror from high particle fluxes, but Mendenhall et al cautioned that coatings that will be irradiated with a (and possibly in a space) a particle (and possibly neutrons) in vacuum should be avoided.