Tailoring the radiation hardness of fused silica

The degradation of optical transmission of two types of Heraeus Suprasil synthetic fused silica after exposure to ionising radiation was investigated with regard to usage as a DIRC radiator. These studies led to the discovery of defect mechanisms that are well known for UV laser irradiation also being present for ionising radiation. The dependence of the optical degradation on interstitial hydrogen, as predicted by existing defect models, could be verified. This leads to an improved understanding of the radiation damage processes and allows to specify the composition of synthetic fused silica according to experimental requirements especially in terms of radiation load.