Scintillation Properties of and Self Absorption in ${\rm SrI}_{2}!:!{\rm Eu}^{2+}$

The scintillation properties of pure SrI₂ and SrI₂ doped with 0.5%, 0.86%, 2%, and 5% europium were studied. Different techniques were used to measure γ-ray excited pulse-height and scintillation decay time spectra, and to perform X-ray excited and optically excited emission spectroscopy. Eu²⁺ emission and trapped exciton (TE) emission was observed in SrI₂:Eu²⁺ samples. These emissions were studied as a function of temperature, Eu concentration, and sample size. A spectral overlap was observed between Eu²⁺ excitation and emission spectra, the amount of overlap depends on temperature. The light yield, energy resolution and luminescence decay profiles reveal also a dependence on temperature, sample size, and Eu concentration. The observations were analyzed and interpreted in terms of two separate models. One model consists of the relation between TE and Eu²⁺ emission and the other deals with self absorption processes.