Radiation effects in commercial off-the-shelf single-mode optical fibres

Several types of commercially available single-mode optical fibres have been irradiated in both gamma and neutron radiation fields to determine the suitability of their use in the readout systems of future particle physics detectors. A comparative survey of the effect of Co-60 gammas and neutrons (<E-a> similar to 6MeV) on different fibre types, including standard germanium doped and pure silica core fibres, has been carried out. Selected fibres were further exposed to gamma radiation at four different dose rates to assess dose rate effects. Results are presented for the dose and fluence levels of interest (110kGy and 1x10(14)n/cm(2)), showing induced losses at 1300nm to be below 0.1dB/m for both types of field. It has been seen that the damage mechanism is the same for both fields. We conclude that many modem Ge-doped fibres will be suitable for use in future particle physics applications, which gives greater freedom of choice to system designers, and greater immunity from the problems associated with single suppliers of specific fibres.