Irradiation tests on optical fibres below 20 K

Up to now no comparison of radiation test results on optical fibers at room temperature and below 150 K was done. However, in some applications much lower temperatures will define the environment, for example at cryogenic accelerator installations or space missions. Qualifying optical fibers for these conditions demands tests at lower temperatures than achievable with liquid Nitrogen or liquid Argon. In this paper we report, for the first time, on radiation-induced attenuation measurements in single-mode optical fibers at extremely low temperatures of 20 Kelvin.