Light yield non-proportionality and energy resolution of Lu1.95Y0.05SiO5:Ce and Lu2SiO5:Ce scintillation crystals

Abstract

The scintillation response of the new Ce-doped lutetium-yttrium oxyorthosilicate (Lu1.95Y0.05SiO5:Ce, LYSO:Ce) crystal was investigated and compared to that of Ce-doped lutetium oxyorthosilicate (Lu2SiO5:Ce, LSO:Ce) crystal. The light yield and energy resolution were measured using photomultiplier tube (XP5200B PMT) readout. For 662 keV γ-rays (137Cs source), the LYSO:Ce showed the light yield of 39,900 ph/MeV, which is higher than that of 35,900 ph/MeV obtained for LSO:Ce:Ce. The energy resolution of 8.2% obtained with LYSO:Ce is better than that of 10.6% obtained with LSO:Ce. The non-proportionality of the light yield and energy resolution versus γ-ray energy were measured and the intrinsic resolution of the crystals was calculated. Over the energy range from 16.6 keV to 1274.5 keV, the non-proportionality of about 35% for LYSO:Ce is better than that of about 42% for LSO:Ce. The photofraction was determined for both crystals and compared with the cross-sections ratio calculated using WinXCOM program.