Determination of neutron background for the studies of in-beam gamma ray spectroscopy using GEANT4

Cross section data of neutron induced reactions is critical for applications in nuclear physics, astrophysics, and nuclear technology. In nuclear physics, it is important to simulate and properly attribute potential contributions to measurements from incidental background reactions. The University of Notre Dame Nuclear Science Laboratory (NSL) has constructed and implemented a neutron beam of 10⁸cm^-2 s^-1 using the ⁷Li(p,n)⁷Be reaction. The flux and energy distribution of neutrons is well characterized. This project is focused on determining the gamma-ray background resulting from the neutrons in the target room. The intent is to determine the feasibility for in-beam inelastic neutron scattering experiments with backgrounds low enough to enable the measurements of gamma-rays of interest. GEANT4 simulations were used to gain a better understanding of the neutron reactions and resulting gamma-rays in the room. The setup was optimized to reduce the neutron background seen by the detector. This project is funded in part by NSF Grant No. PHY-2310059.