Development of BaF₂ Gamma Detectors for Large Angle Gamma Array

The current status of the development of a large-angle array of BaF₂ gamma detectors to measure angular correlations in nuclear cascade events is presented. BaF₂ crystals offer unique advantages for coincidence measurements due to their fast-timing (<1 ns) light emission component. Since the fast-component of BaF₂ light emission occurs in the UV spectrum (~200 nm), the crystals require coating with tetraphenyl butadiene (TPB) for wavelength shifting to enable detection with conventional photomultiplier tubes.

Three gamma detector prototype configurations were constructed, characterized, and compared to each other: a single uncoated BaF₂ crystal, a single TPB-coated BaF₂ crystal, and a dual-BaF₂-crystal assembly with TPB coating. Following characterization, the experimental setup was assembled to perform angular correlation measurements using ⁶⁰Co. The experimental results were compared with Geant4 simulations.