Formation of Radiation-Induced Defects in Silica Glasses at High Irradiation Temperatures

The mechanisms of formation of radiation-induced defects in silica glasses are investigated under both simultaneous and sequential exposure to γ-radiation and high temperatures. It is demonstrated that silica glasses contain E"(T) centers (T = Si and Al) in impurity-free regions andE"^sub M^ (T) centers in the vicinity of alkali metal impurities. These centers can undergo transformations. The origin of a new center responsible for the absorption band at 360 nm is elucidated. This center is identified as a twofold-coordinated aluminum atom with a trapped electron.[PUBLICATION ABSTRACT]