Further studies of the effect of radiation on the mechanical strength of optical fibres

Studies were performed of the mechanical reliability of optical fibre, before and after radiation, to a dose expected for tracking detectors at HL-LHC of 500 kGy(Si). The studies used a 2-point bend test system and were able to determine the fibre stress corrosion susceptibility parameter, n. The comparison of the radiation-induced changes in the n-value allowed us to determine if there was any deterioration in mechanical reliability of the two fibre types tested. The measured n-values for two multi-mode fibres showed some evidence for an increase after radiation which implies that the mechanical reliability of these fibres will not be compromised by radiation to the expected doses at the HL-LHC.