Development of the BaF₂ Large Angle Detector (BaFFLD) Array for Gamma-Ray Angular Correlation Measurements of Nuclear Cascades

Precision measurements of gamma-ray angular correlations in nuclear cascades provide critical information about nuclear structure and can reveal signatures of time-reversal violation. We present the development of the BaF₂ Large Angle Detector (BaFFLD) array designed to measure these correlations with high timing resolution. BaF₂ scintillators offer a fast UV emission component (600 ps decay time), enabling precise coincidence measurements essential for identifying individual cascade events.

The detector array design was optimized using CAD modeling to achieve near-spherical coverage around the target while maintaining practical assembly. The selected design features a cubic support frame with detector holders positioned to maintain spherical detector distribution. The design was imported into Geant4 using CADMesh for performance simulations.

BaF₂ detectors were assembled and characterized using a ⁶⁰Co calibration source, which has a well-known angular correlation function. This experimental data was then verified using Geant4 simulations. An angular correlation analysis algorithm was developed and validated using the experimental setup in Geant4 simulations before application to experimental data.