Gamma-Ray-Induced Absorption Bands in Pure-Silica-Core Fibers

Abstract

Radiation-induced optical absorption bands in pure synthetic silica-core fibers were studied. The effect of Cl contamination on the absorption change of the irradiated fibers in relation to the radiation resistance was examined, and it was deduced that low-Cl fibers have good radiation resistance even when they have a low OH content. The effect of the OH content on the radiation response in low-Cl fibers was thus investigated. The radiation-induced 630 nm band is enhanced in higher-OH-content silica-core fibers. The 660 nm and 760 nm bands were also observed in certain irradiated fibers. The former increases with dose up to 0.1∼2 kGy but decreases at higher doses. The mechanisms of the radiation-induced bands are discussed.