Monte Carlo simulation of the response to fast neutrons of a multi-gap RPC (MRPC) by using the GEANT4 code

This article reports the simulated response to fast neutrons of a multi-gap resistive plate chamber (MRPC) by using the GEANT4 MC code. In this study, a thin polyethylene layer, which acted as the converter material for the detection of fast neutrons, was coated on the surface of the MRPC, which acts as the converter material for the detection of fast neutrons. The converter based on the polyethylene material improved the chamber's ability to detect fast neutrons. By employing the GEANT4 MC code, fast neutrons were inserted into the converter-based MRPC chamber in the energy range of 1.0 - 20.0 MeV. The response of the polyethylene-coated MRPC were evaluated as a function of the neutron energy by using the QGSPBERTHP and the QGSPBICHP physics list with the GEANT4 code. For a 0.13-mm converter thickness, a detection efficiency of 6.4x10-3 were found for fast neutrons with an energy of En = 6.0 by the QGSPBERTHP physics list. The simulation test further confirmed that a higher response of the fast neutrons could be achieved if the converter thickness were to be increased. A detailed outline of the simulation test and the obtained results are presented.