Effect of prior structural defects in quartz fiber lightguides on defect formation by γ radiation

The absorption spectra of unirradiated and irradiated (to fast neutron fluence 10 12 and10 14 cm −2 in VVR-SM) quartz-quartz fibers after additional irradiation with 60 Co γ rays to 10 8 rad are investigated. It is shown that neutrons transform E′ centers into ≡Si-Si≡ centers. The kinetics of accumulation of bridge oxygen atoms under the action of γ radiation exhibits two stages. The first stage is due to neutron irradiation and the manifestation of preliminary potential centers of nonbridge oxygen atoms. The second stage is associated with the creation of additional nonbridge oxygen atoms under the action of γ radiation. The γ-ray dose for the onset of the second stage decreases as the fluence of the preliminary neutron irradiation increases.