Floating zone growth and scintillation characteristics of cerium-doped gadolinium pyrosilicate single crystals

Abstract

Growth of cerium-doped gadolinium pyrosilicate (Gd ₂ Si ₂ O ₇ :Ce) single crystals, which show 2.5 times greater light output for gamma-rays and five times greater light output for alpha particles than GSO single crystals, is accomplished using floating zone growth method (FZ method). Although growth of Gd ₂ Si ₂ O ₇ (GPS) single crystal is considered to be difficult because it melts incongruently according to the phase diagram in a Gd ₂ O ₃ -SiO ₂ system, we attempted crystal growth of Ce:GPS because the possibility exists that heavy Ce doping changes the phase diagram. Transparent single crystals were obtained, but cracks were observed in the crystals. The crystal structure was triclinic with space group P _/1 and density of 5.5 g/cm ³ . Two peaks were observed by photoluminescence spectrum measurement at 374 nm and 394 nm caused by 5d-4f transition in Ce ³⁺ ion. Decay times of Ce:GPS were 46 ns for gamma-ray and 39 ns for alpha particles; its density was 5.5 g/cm ³ . We consider that the energy resolution of 23% will be improved by fabrication of large crystals and improvement of crystal perfectability.