Structure and scintillation of Eu-activated solid solutions in the BaBr2-BaI2 system

We report the structure and scintillation of Eu²⁺-activated solid solutions in the BaBr₂-BaI₂ system. Samples were synthesized in the form of ∼1 mm size crystals by melting the reactants in a sealed quartz tube followed by slow cooling. The solid solutions form an orthorhombic PbCl₂-type crystal structure with an ordered arrangement of the anions. Upon optical and X-ray excitation, the Eu²⁺-activated samples show an intense emission centered between 410 and 423 nm. The samples exhibit a fast decay characteristic of Eu²⁺, with the primary decay time between 315 and 600 ns for ∼75% of the total emitted light. Light yields for the compositions are compared to a newly discovered scintillator, BaBrI:Eu²⁺, measured under identical conditions.