Studies of radioluminescence in fused silica core fibers

Strong radioluminescence band and peaks were observed in fused silica core optical fibers under irradiation in fission reactors of Japan Materials Testing Reactor (JMTR) and in gamma-irradiation facility. A broad band in 400-1700 nm could be attributed to Cerenkov radiation, whose intensity was proportional to inverse of the third power of wavelength. The optical intensity of the peak at 450 nm, that was considered to be generated by oxygen vacancies, was proportional to the reactor power under the electronic excitation dose rate up to 5.0 × 10³ Gy/s, and the dynamic range was at least more than five orders of magnitude. The peak intensity depends on details of silica microstructures and became twice after annealing at 773K. By using these radioluminescence peak and band, wide range dosimetry could be actualized in heavy radiation environments.