Radiation hardness and mechanical durability of Kuraray optical fibers

The radiation hardness of Kuraray 3HF scintillating and clear optical fibers has been investigated using 60Co γ-rays in the dose range 0.4–500 krad. Significant initial degradation in the attenuation length was observed both for 3HF and clear fibers at a dose as small as 10 krad. The radiation hardness of both the scintillating and clear fibers is identical if it is expressed in terms of the ratio of the attenuation lengths after to before irradiation. The radiation damage of 3HF fibers was observed to recover substantially with a time scale of a few months. The attenuation length and mechanical durability against bending were measured for clear fibers by changing S parameter which characterizes the softness of the fibers.