Growth and spectroscopy of BaBrI crystals activated by Eu2+ ions

BaBrI crystals containing 0.01 to 8 mol. % of Eu2+ activator have been obtained. The photo- and X-ray luminescence spectra correspond to Eu2+ 5d – 4f characteristic transitions with a maximum at about 3 eV. The scintillation decay time is 400-500 ns (fast component) and 3700–5500 ns (slow component). It has been established that the decay time in BaBrI crystals depends on the activator concentration. In the absorption spectra of BaBrI: Eu2+ crystals, a double peak is observed associated with 4f7 – 4f65d1 transitions in Eu2+. On the edge of optical absorption, the band gap of 5.2 eV was estimated. We assume the resonant mechanism of energy transfer to the luminescence centers.