The Effect Of Deuterium Ion Bombardment On The Optical Properties Of Beryllium Mirrors

Abstract

Beryllium has a number of unique properties in comparison to all other metals. Due to the fact that it has the highest stiffness to density ratio of all structural metals, beryllium is widely used in components of space satellites, mirrors in particular. As a mirror material, beryllium has a definite advantage over many other metals, namely, its reflectance in the nearest UV (in the wavelength range 0.1–0.25mm) can reach ~60%, i.e., is higher than in the visible range [1]. Because of its lowest atomic number of structural metals, beryllium has been used for about ten years for the protection of vacuum vessel walls in the largest fusion device under operation (JET) [2] and was chosen as a protection material for the experimental fusion reactor (ITER) [3]. In connection with these applications, a great number of experiments have been under way for a long time. These relate different effects of interaction of beryllium with hydrogen isotopes in different energy and flux ranges. However, there have been no publications devoted to the effects of hydrogen isotope ion bombardment on the modification of optical properties of a beryllium mirror. In this paper we describe and analyze results obtained when beryllium mirrors were bombarded over a long period of time by ions of deuterium plasma in the keV energy range.