High-precision simulation of NE213 neutron response using GEANT4.11 with integrated optical transport: Validation against experiments and Monte Carlo codes

This research work accurately simulates the response function of a liquid organic scintillator NE213 (BC501A) detector to fast neutrons in the energy range from 15 MeV to 800 MeV, taking into account the light transport within the detector-lightguide assembly. In contrast to previous studies, which mainly focused on the energy deposited by charged particles and neglected the light transport; this investigation uses the new GEANT4.11 code, which has integrated optical physics functions. This allows an investigation of the effects of the geometry, length, and type of polished and painted lightguide layers on the detection efficiency. The results are compared with experimental data and the output of the multipurpose code MCNPX-PHOTRACK. The analysis shows that the GEANT4 code has a high ability to reproduce optical features and neutron interactions accurately and shows improved agreement with experimental data in the investigated configuration and energy range, particularly when optical photon transport is explicitly modeled.