Radiation-sensitivity enhancement and annealing variation in densified, amorphousSiO2

The influence of ${}_{}{}^{60}{}_{}{}^{}\mathrm{Co}$ γ radiation on densified samples of wet and dry amorphous silica has been studied through the creation and annealing of three intrinsic defects. Radiation sensitivity for oxygen-vacancy creation is enhanced by nearly 2 orders of magnitude in samples densified by only 3%. In general, defect creation efficiency is three to four times larger in wet silica than in dry both in the densified and undensified forms. Diffusion or thermal detrapping models for oxygen-vacancy annealing both suggest the activation energy for annealing increases by 0.6 to 1.0 eV when samples are densified by ∼16%. Creation of the peroxy radical through transformation of oxygen-vacancy centers is discussed.