Radiation-hardness measurements of high content quartz fibres irradiated with 24 GeV protons up to 1.25 Grad

We investigated the darkening of two high OH - content quartz fibres irradiated with 24 GeV protons at the Cern PS facility IRRAD. The two tested fibres have a 0.6 mm quartz core diameter, one with hard plastic cladding (qp) and the other with quartz cladding (qq). These fibres were exposed at about 1.25 Grad in 3 weeks. The fibres became opaque below 380 nm and in the range 580–650 nm. The darkening under irradiation and damage recovery after irradiation as a function of dose and time are similar to what we observed with electrons. The typical attenuation at 455 nm are 1.44 ± 0.22 and 2.20 ± 0.15 dB / m at 100 Mrad for qp and qq fibres, respectively. The maximum damage recovery is also observed near this wavelength.