Thermoluminescence and scintillation of praseodymium-activated Y3Al5O12 and LuAlO3 crystals

Praseodymium-activated Y3Al5O12 (YAG) and LuAlO3 (LuAP) crystals were grown by Czochralski method and their characteristics were investigated. In this paper radioluminescence (RL) spectra, low-temperature thermoluminescence (TL) glow curves, scintillation light yields (LY) and time profiles measured on five samples (2 x 2 x 10 mm(3)), two YAG:Pr (0.1 and 0.3 at%) and three LuAP:Pr (0.003, 0.04, and 0.08 at%), cut from large boules, are reported. RL spectra show three different kinds of emission: host'' emission band (250 nm in YAG, 220 nm in LuAP) clearly visible for lower Pr concentration and at lower temperatures, well-known Pr3+ d-f bands (320 and 370 nm in YAG, 250 and 280 nm in LuAP), and a number of f-f lines (at about 490-500 nm in YAG and 610-620 nm in LuAP). The glow curve of YAG:Pr consists of number of peaks below 200 K. The TL intensity is relatively high, which may result in the lower scintillation light yield measured in a short time window. In the case of TL of LuAP:Pr an interesting phenomenon occurs. The scintillation LY are much higher for YAG:Pr than for LuAP:Pr. The scintillation time profiles in both materials are complex: two-exponential in YAG:Pr and even three-exponential in LuAP:Pr. The fast components are shorter at higher Pr concentration. (C) 2004 Elsevier B.V. All rights reserved.