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Sensitivity of Neutron‑Induced Cross Sections to Pre‑Equilibrium Modelling in EMPIRE 3.2.3 Code

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https://doi.org/10.54963/neea.v5i2.2345
Olorunsola, A. B., Evuti, A. M., Atere, D. A., Abdulrauf, M., & Amanyi, M. I. (2026). Sensitivity of Neutron‑Induced Cross Sections to Pre‑Equilibrium Modelling in EMPIRE 3.2.3 Code. New Energy Exploitation and Application, 5(2), 41–50. https://doi.org/10.54963/neea.v5i2.2345
Volume 5 Issue 2: June 2026
Copyright (c) 2026 Abel Blessing Olorunsola, Abdullahi Mohammed Evuti, Damilola Abubakar Atere, Mudashir Abdulrauf, Matthew Inalegwu Amanyi
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Authors

  • Abel Blessing Olorunsola

    Department of Physics, Faculty of Science, University of Abuja, Abuja 900106, Nigeria
  • Abdullahi Mohammed Evuti

    Department of Nuclear Engineering, Faculty of Engineering, University of Abuja, Abuja 900106, Nigeria
  • Damilola Abubakar Atere

    Department of Physics, Faculty of Science, University of Abuja, Abuja 900106, Nigeria
  • Mudashir Abdulrauf

    Department of Physics, Faculty of Science, University of Abuja, Abuja 900106, Nigeria
  • Matthew Inalegwu Amanyi

    Department of Physics, Faculty of Science, Federal University of Health Sciences, Otukpo 972261, Nigeria

Received: 30 January 2026; Revised: 28 April 2026; Accepted: 18 May 2026; Published: 26 May 2026

Modelling of neutron-induced reaction cross sections is essential for applied nuclear science and nuclear data evaluation. In this study, excitation functions for the reactions 32S(n,p)32P, 35Cl(n,α)32P, and 35Cl(n,p)35S were investigated from threshold energies up to 20 MeV. The calculations were performed using the EMPIRE 3.2.3 nuclear reaction code with different pre-equilibrium model options, namely MSD (Multi-Step Direct), MSC (Multi-Step Compound), PCROSS (Pre-equilibrium cross section), and HMS (Hybrid Monte Carlo Simulation). The theoretical results were compared with available experimental data over a broad energy range up to 20 MeV. The calculated cross sections show good agreement with experimental data near threshold energies, indicating the dominance of the compound nucleus mechanism in this region. However, as the incident neutron energy increases above approximately 5 MeV, noticeable discrepancies emerge among the model predictions, reflecting differences in the treatment of pre-equilibrium processes. In particular, the PCROSS model tends to produce relatively higher cross sections in the energy region between 7 MeV and 12 MeV, where multi-step pre-equilibrium effects become more significant. Overall, the results demonstrate that the choice of pre-equilibrium model has a substantial impact on the predicted cross sections. This study highlights the sensitivity of neutron-induced reaction calculations to reaction-mechanism inputs and provides useful guidance for the appropriate selection of model options within the EMPIRE framework for nuclear data evaluation and related applications.

Keywords:

Energy‑Dependent EMPIRE 3.2.3 Preequilibrium Emission Sensitivity Analysis Sulphur Chlorine Isotopes

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