Effect of γ irradiation on optical components

Optical components operating in radiation environments, like nuclear facilities, high energy physics and space experiments, are exposed to fluxes of energetic particles, which may deteriorate the image quality. In order to avoid unwanted failure of such components that is due to changes produced in the optical properties of the materials by the hostile conditions, it is useful to perform a preliminary investigation of the radiation induced damage on each type of optical component. In this work, coated optical components are investigated. A set of optical coatings were submitted to γ irradiation at the Calliope ⁶⁰Co radioisotope source (Research Centre ENEA-Casaccia, Rome) in order to simulate the hostile radiation environment in which they could be employed. The behavior of different substrates, single-layer materials and multilayer optical coatings was investigated by comparing both transmittance and reflectance measurements before and after the γ-ray exposure.