Proton Irradiation Effects on Dielectric Coatings on Optics

Abstract

Radiation damage on dielectric thin-layer was studied. The dielectric multilayer coating is a promising technology for the use of solar light collection optics in Space Solar Power System (SSPS) in the geostationary orbit. We estimated spatial distributions of numbers of displacement atoms using a Kinchin-Pease model for the proton incidence, and Frenkel pairs created via self-trapped exciton process initiated by electron excitation in the target for the proton and electron incidences. Proton incidence gives damages near the surface of the target due to low energy protons dominating its energy spectrum. Proton irradiation experiment for a thin layer of several dielectric targets shows toughness for about 10-year-equivalent exposure time at geostationary orbit.