Modeling Neutrino Production at the SNS Second Target Station Using Geant4

COHERENT is an international collaboration focused on the measurement of low-energy neutrino cross-sections, such as that of coherent elastic neutrino-nucleus scattering. The Spallation Neutron Source at the Oak Ridge National Laboratory (ORNL) in Tennessee is a high-flux source of neutrinos where COHERENT deploys its suite of detectors. The second target station (STS) is a new neutron source being constructed by ORNL, projected to be finished in the 2030s. The STS will have a 15 Hz pulsed proton beam incident at 1.3 GeV on a rotating assembly of tungsten wedges, leading to pion production and subsequent neutrino generation. As the target design nears a final form, we model its geometry using Geant4 to study the effects of geometric changes on total neutrino and pion production, as well as extensions to the neutrino flux model that incorporate radioactive isotopes.