Radiation-induced Attenuation in Standard Optical Fibers at Cryogenic Temperatures: Dose Rate, Temperature, and Photobleaching Interdependence

The use of optical fiber sensors in ionizing radiation environments is complicated by radiation-induced attenuations (RIAs) that cause significant signal loss as the cumulative radiation dose increases. Moreover, the RIA growth kinetics are strongly dependent on the temperature of irradiation and the intensities of the probe and/or photobleaching lights. Herein, we experimentally investigated the interdependence of the high-dose RIA, radiation dose rate (up to 8.7 Gy s-1), irradiation temperature (down to 15 K), and photobleaching power, in standard optical fibers (SMF28e+). Generally, the RIA increased as a function of dose rate and decreased as functions of temperature and photobleaching power. The experimental high-dose (i.e., saturation) RIA data were fit to a simple kinetic model with quantitative accuracy. Thus, we validate the model, demonstrating that the model accurately captures the interdependence of three key experimental parameters. Using a single set of fiber-specific constants, the saturation RIA was accurately calculated over a broad range of dose rates, temperatures, and photobleaching powers, and across distinct experiments.