Evaluation of solarization resistant optical fibers under gamma-ray irradiation and temperature stress

Five types of large diameter optical fibers (600 μm and 1000 μm core diameter) having either an enhanced UV transmission or being solarization resistant were subjected to gamma-ray irradiation, at a dose rate of 0.3 kGy/h ± 5%, up to a total irradiation dose of 113 kGy, at room temperature. The radiation induced optical absorption in the UV-visible spectral range (200 nm - 450 nm) was monitored, off-line, for each irradiation steps. For some samples, after each irradiation a temperature stress was applied to investigate the thermal annealing of the optical absorption. The dynamics of the irradiation induced color centers was evaluated using a Gaussian deconvolution of the absorption spectra, in the UV spectral range. One of the solarization resistant optical fiber has a very good radiation resistance. This optical fiber loses its quality if it is heated prior to the irradiation. The amplitude and the location of the radiation induced optical attenuation peaks depend on the optical fiber type and the dimension of its core.