Neutron Capture Monte Carlo Simulations for the Alpha-Gamma Device 2.0

The Alpha-Gamma Device 2.0 serves as the neutron beam flux monitor for the larger Beam Lifetime 3 experiment (BL3), which aims to improve systematic measurement precision over previous generations of neutron beam lifetime to 0.3 seconds. A neutron beam flux is calculated entirely from the products of Boron-10 neutron capture within the Alpha-Gamma Device using High-Purity Germanium (HPGe) detectors and silicon detectors to measure gamma and alpha energy spectra, respectively. Geant4, a well-known Monte Carlo particle transport simulation platform, was employed to reconstruct the experimental apparatus and model the detector response to the capture products from thin and thick Boron-10 foils. We present an evaluation of the simulated detector efficiencies and expected background contributions.