Influence of color centers on the luminescent response of radiation-damaged CsI: Tl crystal

Luminescence properties of Tl⁰v_a ⁺ and Tl²⁺v_c ^- color centers induced by irradiation in CsI:Tl crystal are studied within a temperature range of 80-300 K. It is found, that electron Tl⁰v_a ⁺ and hole Tl²⁺v_c ^- color centers arising due to radiation damage do not reduce conversion efficiency of CsI:Tl crystal, but participate in scintillation process to get energy from Tl+ centers by resonance. Degradation of the light yield of the irradiated CsI:Tl crystal is caused by the radiative energy transfer from Tl⁺ to Tl⁰v_a ⁺ centers, whose emission is quenched at temperature above 210 K. Non-radiative energy transfer from Tl⁺ to Tl²⁺v_c ^- centers results in long-wave spectral shift and the duration increase of the scintillation pulse.