Influence of Air Annealing on Optical and Scintillation Properties of YAG:Pr,Ca

Single crystals of yttrium aluminum garnet (YAG) with Pr3+ and Ca2+ ions grown by the vertical Bridgman method are submitted to air anneal. The influence of this process on optical absorption, photo‐, and radioluminescence is investigated in a set of samples with different concentrations of Pr and Ca. Absorption induced by the heat treatment in the 300–600 nm range in YAG:Pr,Ca is discussed, in comparison with that in YAG:Ca crystals. Photo‐ and radioluminescence spectra in as‐grown and air‐annealed samples recorded at room temperature are discussed. The features of emission decrease at 5d–4f and 4f–4f transitions of Pr3+ ions after heat treatment are considered. Defects formed by Ca2+ have a strong contribution to absorption induced in YAG:Pr,Ca by air annealing. The decrease in intensities of Pr3+ emissions in photoluminescence spectra with increase of Pr and Ca correlates with the induced absorption due to annealing, while the mechanism of energy transfer under X‐ray excitation is different toward the d and f states.