Limitations of the performance of PWO-II crystals due to radiation damage

The presented paper documents the overall quality of the PWO-II crystals for the PANDA electromagnetic calorimeter focusing in particular on the radiation hardness and the consequences on the operation at T=-25°C. The imposed radiation damage due to ¿-rays can be significantly cured applying the process of stimulated recovery, which was observed for the first time for PbWO₄ scintillators. The fast recovery can be achieved even using photons in the infrared region and can be applied to operating detectors parallel to damaging irradiation in case the photo sensor is not sensitive to the external light. The technological application is part of a submitted patent (TM-382-DE).