Mechanism of E' center induced by γ ray radiation in silica optical fiber material

The characteristics of the best known defect centers E' in silica optical fiber material irradiated with γ ray were investigated by ESR at room temperature. A mechanism model of production of the E' center defect was established. The production of E' center includes two processes creation and activation. The strained bonds (or oxygen replacement) in silica networks lead to the creation of new defects whose concentration increases linearly with the dose. The pre-existing defects produce the activation, which tends to saturation. According to this model, the relation of E' center concentration changing with irradiation dose was obtained theoretically. The results are in good agreement with the experimental results. (authors)