Comparison of absorption, luminescence and scintillation characteristics in Lu1.95Y0.05SiO5:Ce,Ca and Y2SiO5:Ce scintillators

• Commercial LYSO:Ce,Ca and YSO:Ce single crystals are compared.
• Ca2+ codoping in LYSO:Ce,Ca converts a part of the Ce3+ centers into Ce4+.
• Ce4+ center is not harmful for scintillation efficiency in LYSO:Ce,Ca.
• YSO:Ce scintillation response is deteriorated by slower host–Ce energy transfer.

The absorption, luminescence and scintillation characteristics of Y2SiO5:Ce (YSO:Ce) scintillator were investigated and compared to those of Lu1.95Y0.05SiO5:Ce,Ca (LYSO:Ce,Ca) scintillator. Due to the Ca2+ co-doping in LYSO:Ce quantified by GDMS analysis, the Ce4+ center is evidenced in the absorption spectra. For 662 keV γ-rays (137Cs source), YSO:Ce shows a light yield of 15,300 ph/MeV, which is much lower than that of 32,000 ph/MeV obtained for LYSO:Ce,Ca. The coincidence timing resolution for 511 keV annihilation quanta of 234 and 478 ps was obtained, respectively, for LYSO:Ce,Ca and YSO:Ce detectors in coincidence experiment using a BaF2-based detector. Time resolution was also discussed in terms of a number of photoelectrons and decay time of the scintillation pulse.