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Results of imitation experiments on effects of charge exchange atoms bombardment on optical properties of metallic mirrors (in the spectrum range of 200–800 nm) are presented. The long-term sputtering of mirror samples made of stainless steel, copper and hot pressed beryllium have been carried out with plasma ions (H + , D + , He + , or Ar + ) of keV energy range. It was shown that in the case of a stainless steel mirror, the sputtering of a layer of ∼2 μm thick did not lead to significant change in reflectivity. As to a copper mirror, a noticeable change of reflectivity was observed after sputtering of ∼0.7 μm layer using He + ions. The highest rate of degradation, especially in the UV region, was found in the case of beryllium mirrors.

This paper consists of two parts and concerns the influence of fusion reactor conditions on inner elements of some diagnostic systems. The first part is devoted to results of imitation experiments on the long-term operation of plasma-viewing mirrors, and in the second part there are discussed the results on a possibility to use carbon-graphite materials for fabricating the active elements of mm and sub-mm diagnostics (radiating and receiving antennae, reflectors). It is evident that results of the second part can be useful only in the case that carbon-based materials but not a beryllium will be chosen as the first wall protection.