LuAlO3:Ce-a high density, high speed scintillator for gamma detection

We present measurements of the scintillation properties of cerium doped lutetium aluminum perovskite, LuAlO₃:Ce, a new dense (ρ=8.34 g/cm³) inorganic scintillator. This material has a 511 keV interaction length and photoelectric fraction of 1.1 cm and 32% respectively, which are well suited to gamma ray detection. In powdered form with 0.5% cerium concentration, the scintillation light output is estimated to be 9,600 photons/MeV of deposited energy, the emission spectrum is a single peak centered at 390 nm, and the fluorescence lifetime is described by the sum of 3 exponential terms, with 60% of the light being emitted with a 11 ns decay time, 26% with a 28 ns decay time, and 13% with a 835 ns decay time. Single crystals contaminated with ≈10% lutetium aluminum garnet (Lu₃Al₅O₁₂) have significantly altered scintillation properties. The light output is 26,000 photons/MeV (3.2 times that of BGO), but the decay time increases significantly (1% of the light is emitted with a 10 ns decay time, 15% with a 245 ns decay time, and 85% with a 2010 ns decay time) and the emission spectrum is dominated by a peak centered at 315 nm with a secondary peak centered at 500 nm. The short decay lifetime, high density, and reasonable light output of LuAlO₃:Ce (the perovskite phase) suggest that it is useful for applications where high counting rates, good stopping power, good energy resolution, and fast timing are important. However, it is necessary to grow single crystals that are uncontaminated by the garnet phase to realize these properties