A study of radiation resistance of silica optical fibers under conditions of reactor irradiation.

A measuring system has been developed to investigate the characteristics of radiation-induced optical absorption and radioluminescence in the spectral range of 400–1000 nm for a set of optical fibers being irradiated by fast neutrons and γ rays. This system has been used on the IR-8 research nuclear reactor to perform comparative tests of eight types of silica optical fibers from Heraeus (Germany), Fujikura (Japan), Mitsubishi (Japan), and the Fiber Optics Research Center of the Russian Academy of Sciences’ Prokhorov General Physics Institute. The measured dependences of the induced absorption and radioluminescence intensity versus the nuclear radiation wavelength, flux, and fluence, as well as the temperature, are analyzed. The microscopic mechanisms of induced absorption and radioluminescence are discussed. The values of induced optical absorption and radioluminescence in glass fibers containing H₂ gas and having a hermetic coating (the technology for producing such fibers has been developed by the Fiber Optics Research Center) is found to be many times smaller than in other fibers. [ABSTRACT FROM AUTHOR]