Influence of lutetium content on the scintillation properties in (Lu x Y1−x )AlO3 :Ce single crystals

Abstract

The absorption, luminescence, and scintillation characteristics of cerium-doped lutetium-yttrium perovskite (LuxY1−x AlO3:Ce; x = 0, 0.3, 0.7) single crystals were investigated. The values of light yield, scintillation decay time, and coincidence time resolution were evaluated. At 662 keV γ-rays (137Cs source), the light yield of 30 700 ph MeV−1 obtained for YAlO3:Ce is much higher than that of 16 200 and 10 600 ph MeV−1 obtained for Lu0.3Y0.7AlO3:Ce and Lu0.7Y0.3AlO3:Ce, respectively. Scintillation decays are dominated by a fast component with decay time value of 16–20 ns, which nearly coincides with the photoluminescence decay time value of 17.5 ns. In scintillation decays the intensity of the fast component becomes reduced and the content of slower components considerably increased with increasing lutetium content in the crystals. The coincidence time spectra for 511 keV annihilation quanta were measured in coincidence experiment using a BaF2-based detector and time resolution was also discussed in terms of a number of photoelectrons and decay time of the scintillation pulse. The photofraction for all the crystals under 662 keV γ-ray excitation was also evaluated and discussed.