Masaharu Ooe

Gamma-Ray Irradiation Effect on Loss Increase of Single Mode Optical Fibers, (I): Loss Increase Behavior and Kinetic Study

Gamma-ray induced losses of pure silica core and GeO2 added core single mode optical fibers (Si-SMF and Ge-SMF) at 1.30 μm were investigated. Kinetic study on recovery curves of their γ-ray induced losses, showed that the induced loss could be divided approximately into two terms: one is dependent mainly on total dose and the other is dependent on dose rate, which has a tendency toward saturation when increasing total dose and was also represented by 3 components with different relaxation times The former term which is dependent mainly on the total dose was found to be due to IR tail absorption caused by irradiation and to be associated with the Si-E′ center for the Si-SMF and the Ge(l) and Ge(2) centers for the Ge-SMF, respectively.

Gamma-ray irradiation effect on loss increase of single mode optical fibers, II. Estimation of loss increase due to long term irradiation

In order to examine the reliability of optical fiber systems in nuclear power plants, we estimated the induced losses of pure silica core and GeO 2 added core single mode optical fibers (Si-SMF and Ge-SMF) exposed over a long period to low dose rate γ-rays (less than 100 R/h, 40 yr). Also γ-ray induced losses under a high dose rate and high temperature condition such as 10 6 R/h and 200 o C were estimated in view of an accident. In both cases, the induced losses were concluded to depend mainly on total dose from the results of low dose rate irradiation experiments and a study on temperature dependences of induced losses