Growth and scintillation properties of Tl-doped CsI/KI/KCl ternary eutectics

In this study, Tl:CsI/KI/KCl eutectic scintillators were grown using the Bridgman–Stockbarger method by unidirectional solidification. The eutectic phases were uniformly distributed in the transverse direction and were slightly aligned along the growth direction. The Tl:CsI scintillator phase was grown as a matrix, which was then used for creating optical waveguides of the scintillation light. The expected Tl+ emission peak was observed at 486 nm under X-ray excitation and cathodoluminescence; this was attributed to the self-trapped exciton perturbed by TI+ in Tl:CsI. The decay time of the Tl:CsI/KI/KCl eutectic was 313 ns, and its light output was estimated to be 22,000 photons/MeV.