Ce-doped scintillators: LSO and LuAP

In this paper we compare the scintillator performance of the two of the leading contenders for Positron Emission Tomography, both cerium doped: Lu2SiO5 (LSO) and LuAlO3 (LuAP). LSO crystals come in two categories, characterized by high (H) or low (L) light output. Such a distinction is not found in LuAP, but its output is consistently lower than that of LSO-H. Based on decays, thermoluminescent data and dependence of light output on temperature, we conclude that the principal reason for the superior properties of LSO-H is its virtual absence of shallow traps. LuAP also suffers from an additional handicap in the form of a parasitic absorption of unknown origin, which causes a light output dependence on the thickness of the sample.