Scintillation properties of GSO

The timing properties of Gd/sub 2/SiO/sub 5/:Ce (GSO) single-crystal scintillators have previously been evaluated for positron emission tomography applications. The measured time resolution, however, was worse than expected from calculations based on photoelectron yield and a 60-ns exponential decay constant, leading the authors to further investigate GSO's basic properties. With a time-correlated-single-photon technique, they found two decay components, one of 56 ns and one of 600 ns, the latter containing 10-15% of the total scintillation output. This may explain the difference between the experimental and theoretical time resolutions and confirms a previous hypothesis of a long decay component. In addition, it was found that the decay constant of each component strongly depends on the cerium concentration. The primary component varies from approximately 20 ns to approximately 190 ns and the secondary component varies from approximately 70 ns to approximately 1200 ns as the cerium concentration is varied from 5.0 mol.% to 0.1 mol.%.<
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