Scintillation properties of cerium-doped gadolinium silicate with γ-rays from 137Cs

The temperature dependence of the scintillation time profile of a cerium-doped gadolinium silicate (GSO:Ce) crystal has been measured with 662 keV γ-rays from 137Cs between 303 and 464 K. A scintillation mechanism has been assumed where electrons and holes created by radiation are recombined at Ce3+ color centers and scintillation light is emitted by the de-excitation of excited Ce3+ ions. The pulse shapes have been fitted with a function derived based on this mechanism. The functional form of the pulse shapes was consistent with the data. The obtained decay time constants for the fast and slow components of the de-excitation of excited Ce3+ ions have been explained using radiative decay time constants and non-radiative decay time constants. The radiative decay time constant has been evaluated to be 52.0±1.1ns and the activation energy has been evaluated to be 0.246±0.036eV for the fast component using the function of the temperature dependence of the non-radiative decay time constant.