Investigation of Fiberoptics during and after Fission Product Gamma Irradiation

The transmission losses and possible annealing methods with various glasses and fiberoptics were studied after fission product gamma irradiation. Irradiation was performed in the thermal column of the 250 kW TRIGA Mark II reactor, Vienna, and transmission losses in visual range were investigated by optical spectrometry. A total of 6 glass samples and 3 fiberoptic samples have been exposed to gamma doses varying from 8 × 104 R to 2.3 × 109 R. Thermal annealing parameters were studied at 300 C, 400 C and 500 C, optical annealing was performed by an arc lamp, by an UV-light source and by a pulsed UV-laser. In addition thermal annealing experiments were carried out simultaneously to gamma exposure resulting in shorter annealing periods and lower temperatures.