Influences of Thermal Annealing Temperatures on Irradiation Induced $E^{\prime}$ Centers in Silica Glass

Influences of pre-irradiation and thermal annealing on
E

^'
defect concentration are studied by measuring
E

^'
centers and optical absorptions using ESR and spectrophotometer, respectively. The results show that the
E

^'
defect concentration decreases significantly when silica glass is pre-irradiated by gamma rays and a subsequent thermal annealing. The effect of thermal annealing on the
E

^'
concentration has also been investigated for the temperature from 300degC to 1300degC. It is found from the ESR spectrum that the anti-irradiated property of the silica glass can be improved when the thermal annealing temperature is larger than 700degC. These results have been proved by optical absorption spectra.