Scintillation Properties of Lu $_0.4$ Gd $_1.6$ SiO $_5$ :Ce (LGSO) Crystal

We have developed Lu $_0.4$ Gd $_1.6$ SiO $_5$ :Ce (LGSO) crystals as a new scintillator for medical applications. Scintillation properties of LGSO crystal of various Ce concentrations and their dependence on annealing effect were studied. Its absorption coefficient at 511 KeV gamma rays is 0.70 cm $^-1$ . We observed that the light output and decay time are dependent on the Ce concentration in the crystal. Decay constant decreases with increasing Ce. Annealing of the colored crystal having 2.0 mol% Ce makes it colorless with better scintillation properties: large light output (40% of NaI:Tl), good energy resolution (8.3% for 4 $,times,$ 6 $,times,$ 20 mm $^3$ crystal) and fast decay constant (65 ns of primary component and 180 ns of secondary component).