Growth of thallium-doped CsI/CsCl/KCl eutectics and their scintillation properties

In this study, Tl:CsI/CsCl/KCl ternary eutectic scintillators were grown using the vertical Bridgman–Stockbarger method by unidirectional solidification. The CsI and KCl phases were elongated along the growth direction, based on backscattered electron imaging (BEI) observations. The Tl:CsI scintillator phase grew as a matrix, which can be used to create optical waveguides for scintillation light. The expected Tl+ emission peak was observed at 550 nm under X-ray excitation. This emission was attributed to the self-trapped excitons perturbed by TI+ in Tl:CsI. The decay time of the Tl:CsI/CsCl/KCl eutectic was 285 ns, and its light output was estimated to be 10,800 photons/MeV. •A novel ternary CsI/CsCl/KCl eutectic scintillator is grown by the VB method.•The CsI matrix phase elongates in the growth direction, serving as a scintillator.•The expected Tl + emission peak near 550 nm is observed in the CsI phase.•The decay time of the eutectic is 285 ns.•The light output of the eutectic is approximately 10,800 photons/MeV.