Progress in the development of LuAlO$_{3}$ based scintillators

LuAlO/sub 3/:Ce/sup 3+/ (LuAP) and Lu/sub x/Y/sub 1/-xAlO/sub 3/:Ce /sup 3+/ (LuYAP) crystals are used as scintillation materials for positron emission tomography. The actual study of these scintillators develops in three directions: (i) growth of large size LuAP crystals with stable properties, (ii) the relationship between the composition of LuYAP crystals and scintillation properties, and (iii) scintillation mechanisms in lutetium compounds. After improving of growth conditions a large size samples (length >40 mm) have been prepared. Crystals show a good correlation between growth parameters, light yield and transmission spectra. We studied a series of samples with calibrated size (2*2*10 mm3) and compare the light yield with standard BGO and LSO samples. Mixed crystals with composition of 0.6<x<0.8 show a significant increase of light yield. We suggest that the short order clusterisation in mixed crystals may play an important role in governing the scintillation efficiency. In order to clarify the scintillation mechanism in LuAP and LuYAP crystals measurements of absorption, emission and excitation spectra, thermoluminescence and scintillation decay curves have been performed. (0 refs).