Effect of gamma-quanta and fast neutrons on color and emission centers in LuAG and LuAG:Pr crystals

Abstract Optical absorption, photo-excitation and photo- and gamma-luminescence spectra of nominally pure LuAG crystal and praseodymium doped LuAG:Pr scintillation detector were compared prior and after irradiations with 60Co gamma-quanta in the dose interval 102–106 Gy and reactor fast neutron fluencies 1016 and 1017 cm−2 accompanied by gamma radiation. The optical absorption of LuAG:Pr does not exceed 1 cm−1 in the range of 2.06–4.3 eV within the used gamma-dose interval. The gamma-luminescence of Pr3+ activator at 4.0 eV decreases by ~9% due to reabsorption by Cr4+ and is stable within 103–106 Gy. Fast neutron and gamma fluxes generate Frenkel pairs by elastic and inelastic mechanisms. Electron F- and F+-centers, hole O− centers, and also impurity Fe3+ centers suppress by 50% the Pr3+ emission by means of reabsorption after neutron fluency 1016 cm−2. The LuAG:Pr crystals can be recommended as a scintillator detector for applications involving neutron and gamma radiations at gamma-dose up to 106 Gy and fast neutron fluencies up to 1012 cm−2.