Methodology for prediction of near-Earth space radiation effects on optical glasses

Prediction of near-Earth space radiation impact on spectral transmission of optical glasses remains an issue after several decades of research. The very wide range of multicomponent commercial glasses, radiation types, total doses, doses rates, etc. question the possibility of ab initio assessment of radiation impact. It has been proposed that a pragmatic parametric approach has merit in such a situation. We use BK7 glass as an example to demonstrate how the problem can be approached. Based on a sequence of transmission spectra measured in the course of and after gamma-irradiation (Co⁶⁰ source), we show how to find the required parameterization set. Taking into account the number of optical glasses used in space optical instruments, it is proposed that the first step toward a useful radiation effects database consists of the elaboration of a uniformly applicable methodology for testing of optical glasses. We believe that our work can serve as a basis for that methodology.