Optical systems operating in space must maintain their performance over long mission times. Glasses are well known to darken upon exposure to radiation, due to formation of color centers, resulting in performance degradation. Despite increasing demand, an approach which would allow accurate prediction of the end-of-life performance characteristics of space optical instruments, has not been elaborated yet. We propose here a phenomenological methodology that should help to solve the problem. In our model, functional dependencies describing defect generation and annealing are derived from mathematical models, taking into account dose levels and irradiation times relevant for space missions. Numerical values for the parameters come from experimental data. Our experimental methodology is also described. We apply this model to analyze the results obtained for BK7 glass subject to Co⁶⁰ gamma-radiation.

Date Published: 28 January 2002
PDF: 8 pages
Proc. SPIE 4547, Photonics for Space and Radiation Environments II, (28 January 2002); doi: 10.1117/12.454388

Published in SPIE Proceedings Vol. 4547:
Photonics for Space and Radiation Environments II
Francis Berghmans; Edward W. Taylor, Editor(s)