Defects induced by irradiation at room temperature in cerium fluoride

One of the crucial parameters of Cerium Fluoride (CeF3) which is currently among the best candidates for large electromagnetic calorimeters in future High Energy Physics experiments is the radiation hardness. Several Cerium Fluoride crystals from different producers and with different doping conditions have been irradiated at room temperature with gamma-rays at different doses. The behaviour of induced radiation damage has been studied by systematic measurements of absorption spectra with non polarised and polarised light. The saturation of radiation damage in function of the dose, the recovery at room temperature, the optical and thermal bleaching of the damage have been investigated. Based on these experimental results, a tentative explanation of the defects induced by irradiation at room temperature will be given.