Radiation response evaluation of pure silica core image guides

We have proposed a method of evaluating radiation resistivity of image fiber bundles for remote visual observation by human eyes. The method is more effective than the conventional one for evaluating telecommunications fiber. The evaluation results are expressed by average visual induced losses which were transferred from the in-situ radiation induced spectral losses by using spectral luminous efficiency in consideration of human perception. Based on the results, estimates were made on the average induced losses under the total doses exceeding the experimental limit and with varied image guide lengths exposed to radiation, respectively. Comparison of the average induced losses with the actual deterioration in the pictures observed in-situ allows to calculate maximum allowable average induced losses for varied applications, showing the possibility of precisely assessing the lifetime of image guides in radiation fields with the conditions similar to actual observation. (author)