Transient optical phenomena in quartz fibers under high-power pulsed reactor irradiation

Measurements of the intensity of emission and induced optical absorption at 400–750 nm in KU-1 quartz fibers were performed under pulsed irradiation in a BARS-6 reactor (pulse duration, 80 μs; dose per pulse, up to 5×10¹² neutrons/cm² (E>0.2 MeV); dose rate, up to 10⁵ Gy/s). The nondelayed emission component is due to the Cerenkov radiation, the weak relaxation component has a relaxation time of ～150±50 μs, and the radiation-induced optical absorption reaches a value of 2.5×10^?4 cm^?1 (relaxation time, 600–1200 μs). A nonlinear dependence of the Cerenkov radiation on the dose rate and the presence of the relaxation emission component and the transient optical absorption may be associated with an optical inhomogeneity of glass induced by the high-power reactor irradiation.