MECHANISM OF LUMINESCENCE FROM A CERIUM-DOPED GADOLINIUM ORTHOSILICATE (GD2SIO5) SCINTILLATOR

Time dependence of luminescence in a Ce-doped Gd2SiO5 scintillator has been measured as a function of the Ce concentration ranging from 0.1 to 0.95 mol% and of the temperature ranging from 170 to 330 K. It has been shown that the time dependence of the luminescence has a fast rise of about 3 ns which corresponds to a lifetime of excited Ce3+ and a decay time up to 2 μs. This decay is not described by a single exponential curve and becomes faster with increasing Ce concentration and with increasing temperature. These experimental results of the decay curves are well explained by the recombination luminescence model which is associated with electron-capture Ce3+ (i.e. Ce2+) and self-trapped holes (i.e. Vk-centers), by considering a probability of hot-electron escape from the ideal tube of coulomb attraction. Cross sections for the recombination between Ce2+ and Vk-centers are estimated to be 3.2 × 10-16 cm2 at 295 K and to be 1.7 × 10-16 cm2 at 230 K. © 1990.