LuAP/LuYAP single crystals for PET scanners: effects of composition and growth history

In this paper we present results of optical and scintillation studies of three series of LuAP and LuYAP crystals differing in yttrium and cerium concentrations. Comparison of as-grown and UV-irradiated crystals has revealed two types of color centers located at 200–240 nm and 250–320 nm and giving rise to underlying absorption. The percentage of light emitted at 1 μs increases from 76% in LuYAP (Lu80%) to 85% in LuAP but is dependent on Ce concentration too. The light output for the best LuYAP and LuAP specimens of 2 × 2 × 10 mm ³ measured in the vertical geometry was 50% of LSO and 35% of LSO respectively.