First mirrors for diagnostic systems of an experimental fusion reactor I. Simulation mirror tests under neutron and ion bombardment

Among the diagnostic systems planned for use in the International Thermonuclear Experimental Reactor to control the reactor operation, a large number of these systems have to use the mirrors to input or output the electromagnetic radiation to or from the burning plasma in different parts of the spectrum. The mirrors placed inside the vacuum vessel will be subjected to the impact of several factors, resulting in degradation in their optical characteristics. The most critical factors are erosion under the bombardment with a flux of high-energy particles, deuterons and tritons, and the deposition of the products of erosion of the in-vessel components. The first part of this review presents the results of the simulation experiments studying the effect of sputtering and deposition of contaminants on the optical properties of mirrors fabricated from different materials. In the second part of the review, the results of mirror testing on the operating large-scale fusion devices are considered.