Scintillation kinetics of YSO:Ce

Compared to the fast rise and exponential decay of Lu₂SiO₅:Ce, Y₂SiO₅:Ce has a slower rise time and a non-exponential decay. In an effort to understand this difference, the scintillation kinetics of YSO:Ce were investigated as a function of X-ray and gamma-ray energy as well as under alpha particle excitation. Although some influence of excitation energy and energy density on the kinetics was observed, in no case did the behavior match LSO:Ce. Therefore, a further investigation using thermoluminescence techniques probed the effect of electron traps on the rise and decay times. TL glow curves revealed several large trap populations, particularly near 100 K. The participation of the traps in the scintillation process was eliminated by making scintillation decay time measurements at 40 K, and a time profile similar to LSO:Ce was observed, possibly because the traps do not release electrons at this low temperature and only direct energy transfer to Ce luminescence centers contributes to the observed scintillation time profile.