PWO crystals for CMS electromagnetic calorimeter: studies of the radiation damage kinetics

Kinetics of radiation damage of the PWO crystals under irradiation and recovery were studied. Crystals were irradiated with dose corresponding to average one expected in the electromagnetic calorimeter (working dose irradiation). Radiation damage and recovery were monitored through measurements of PWO optical transmission. An approach is proposed which allows evaluating the influence of the PWO crystals properties on the statistical term in the energy resolution of the electromagnetic calorimeter. The analysis also gives important information about the nature of the radiation damage mechanism in scintillation crystals. The method was used during development of technology of the mass production of radiation hard crystals and during development of methods for crystals certification