PROPERTIES OF THE NEW LUAP-CE SCINTILLATOR

The scintillation properties of LuAP (lutetium aluminum perovskite, Lu AlO3) have been investigated at three different levels of Ce doping: g reater than or equal to 0, 0.035 and 0.105 mol%. The light yield, in p hotoelectrons per MeV, was measured as 122 +/- 20, 1300 +/- 100 and 28 50 +/- 200, respectively. The light pulse shapes were largely exponent ial, with a decay constant of 16.5 +/- 1 ns for all the samples studie d. In all cases, however, an additional slow component, amounting to a bout 10 +/- 3% of the total light, was also found, characterized by a time constant of 74 +/- 7 ns. The sample doped with 0.105 mol% Ce show ed an energy resolution of 9.3% for the 662 keV full energy peak from a Cs-137 source. The high detection efficiency of the material for gam ma-rays (because of its high density of 8.4 g/cm(3)) is confirmed by a photofraction of about 13% for a specimen with a volume of only 0.05 cm(3). The time resolution for Co-60 gamma-rays at a 1 MeV threshold w as measured as 160 ps, somewhat poorer than expected. Nevertheless, th e high light yield, fast light pulse, high detection efficiency for ga mma-rays and excellent time resolution make this material a very attra ctive scintillator, particularly in positron emission tomography.