Exploring the radiation hardness of lead glass detectors used in the COMPASS experiment

In order to study the influence of possible radiation damage on the performance of the lead glass detectors used in the electromagnetic calorimeters of the COMPASS spectrometer at CERN, lead glass modules were irradiated. irradiated with gamma-rays from a 60Co source and high energy electrons delivered by the MAMI accelerator. Two different lead glass types (TF1 and SF57) were investigated. We measured the thermoluminescence after irradiation and determined the natural recovery from radiation damage at room temperature as well as the recovery induced by optical bleaching. We also discuss consequences for the operation of this detector in future runs of COMPASS with high beam intensities.