Study of neutron detection efficiencies for liquid organic scintillator up to 3 GeV

The Monte Carlo code, designated SCINFUL-QMD, has been developed to calculate neutron detection efficiency up to 3 GeV for liquid organic scintillators such as NE-213. The existing Monte Carlo code, SCINFUL, is known to reproduce a response function and detection efficiency at incident neutron energies below 80 MeV. We incorporate the quantum molecular dynamics plus statistical decay model (QMD + SDM) into SCINFUL to extend the upper limit of incident neutron energy to 3 GeV. The tabulated cross sections adopted in SCINFUL are extrapolated up to 150 MeV, and the (QMD + SDM) method is used above 150 MeV. The results of SCINFUL-QMD are compared with the experimental data and those of CECIL, another computation code. At energies below 20 MeV, the results of SCINFUL-QMD agree with the experimental data. At higher energies, this code gives smaller values than those of the experimental data. SCINFUL-QMD exhibits an increase in detection efficiency above 300 MeV. This result is achieved by taking charged pion production into account.