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Low temperature (~35 K) measurements of the scintillation kinetics of [Y.sub.2]Si[O.sub.5] : Ce (YSO:Ce) have previously illustrated that shallow electron traps can play an important role in the scintillation mechanism. In addition, divalent calcium co-doping of isostructural [Lu.sub.2]Si[O.sub.5] : Ce (LSO:Ce) has been shown to eliminate shallow electron traps and decrease scintillation decay time while maintaining high light output. Here we investigate the effect of [Ca.sup.2+] codoping on the trap populations and scintillation kinetics of YSO:Ce. Single crystals were grown with [Ca.sup.2+] concentrations up to 0.5 at % relative to Y. Thermoluminescence measurements indicate a significant reduction in shallow traps, and a marked change in the scintillation kinetics can be seen in the scintillation time profiles as a result of [Ca.sup.2+] codoping. Index Terms--Decay time, scintillation, YSO.

The temperature dependence of scintillation decay and rise time was measured for GGAG:Ce and Ca-codoped GGAG:Ce crystals in the temperature range of 10 K to 400 K. The decay and rise times were found to increase with decreasing temperature in the case of GGAG:Ce crystals, while Ca codoping modifies the kinetics such that decay and rise times are constant with the change in temperature. In order to obtain a better understanding of the role of trap centers in the temperature dependence of scintillation kinetics, spectrally resolved thermoluminescence (TL) properties were also studied for these crystals. [ABSTRACT FROM PUBLISHER]

The temperature dependence of the photoluminescence properties of Gd2SiO5:Ce,Ca crystals was found to be significantly affected by Ca codoping and shows that presence of additional energy levels in these crystals provides nonradiative energy transfer. The excitation and emission bands also broaden with codoping due to presence of these additional energy levels. Therefore Ca codoping in Gd2SiO5 crystals decreases the scintillation decay very strongly and has a strong adverse affect on scintillation light yield, different from the effect in other members of the oxyorthosilicate family such as Lu2SiO5 and Y2SiO5. [ABSTRACT FROM PUBLISHER]

Low temperature (∼35 K) measurements of the scintillation kinetics of Y2SiO5 : Ce (YSO:Ce) have previously illustrated that shallow electron traps can play an important role in the scintillation mechanism. In addition, divalent calcium co-doping of isostructural Lu2SiO5 : Ce (LSO:Ce) has been shown to eliminate shallow electron traps and decrease scintillation decay time while maintaining high light output. Here we investigate the effect of Ca2+ codoping on the trap populations and scintillation kinetics of YSO:Ce. Single crystals were grown with Ca2+ concentrations up to 0.5 at% relative to Y. Thermoluminescence measurements indicate a significant reduction in shallow traps, and a marked change in the scintillation kinetics can be seen in the scintillation time profiles as a result of Ca2+ codoping. [ABSTRACT FROM AUTHOR]