Implementation of a Geant4-based code using low-energy gamma-nuclear final state model for photonuclear studies

In this work, we developed a Geant4-based code, IS-2020, for photonuclear studies below 200 MeV covering the giant dipole resonance region (GDR). It uses G4LowEGammaNuclearModel, which consists of preequilibrium and equilibrium reaction mechanisms, for sampling the final states of photonuclear reactions. Simulations for photonuclear reactions on 96Mo, 90Zr, and the strongly-deformed nucleus 153Eu targets have been performed for its validation. Moreover, a good agreement was also observed between experimental relative yields and the simulation results of 59Co(γ,2n)57Co and 50Cr(γ,2n)48Cr reactions induced by bremsstrahlung. The implemented code will be a useful and reliable tool for photonuclear studies, including designing the experimental setup, estimating the yield of outgoing products, and interpreting the measured data.