Barium iodide single-crystal scintillator detectors

We find that the high-Z crystal Barium Iodide is readily growable by the Bridgman growth technique and is less prone to crack compared to Lanthanum Halides. We have grown Barium Iodide crystals: undoped, doped with Ce³⁺, and doped with Eu²⁺. Radioluminescence spectra and time-resolved decay were measured. BaI₂(Eu) exhibits luminescence from both Eu²⁺ at 420 nm (~450 ns decay), and a broad band at 550 nm (~3 μs decay) that we assign to a trapped exciton. The 550 nm luminescence decreases relative to the Eu²⁺ luminescence when the Barium Iodide is zone refined prior to crystal growth. We also describe the performance of BaI₂(Eu) crystals in experimental scintillator detectors.