Study on the damaging process of silica by in-reactor luminescence

We have carried out in situ luminescence measurements of silica glasses in a fission reactor. In the in-reactor-luminescence (IRL) spectra, the 300-nm band was observed for all the samples and its intensity stayed constant du ring irradiation. For low-OH fused silica glass, the 400-nm IRL band was al so observed and reduced rapidly with irradiation, while for high-OH fused a nd synthesized silica glasses, the 450-nm IRL band grew slowly. The compari son with photoluminescence (PL) and electron spin resonance (ESR) spectra s howed that the decrease of the 400-nm IRL band reflects the transition of B -2 beta center to E' center by electron excitation by gamma -rays, while th e growth of the 450-nm IRL band related to defect formation from neutron ir radiation. However, single crystal silica showed only a 300-nm IRL band, su ggesting that the damaging processes are influenced by the local structure around defects as well as the OH content in silica. (C) 2000 Elsevier Scien ce B.V. All rights reserved.