Accelerator-based neutron sources: A GATE simulation study of quasi mono-energetic neutrons

⁷Li(p,n) and ⁹Be(p,n) are two of the most widely used nuclear reactions for the accelerator-based, fast quasi-monoenergetic neutron sources across various industrial, medical, and scientific fields at different proton energies. However, limited data exists in the 10-40 MeV incident proton energy range, highlighting a gap in experimental and simulation studies. To address this, we investigated accelerator-based quasi-monoenergetic neutron sources by simulating neutron production through proton interactions with ⁷Li, ⁹Be, and ¹¹B targets using the GATE Monte Carlo toolkit, based on GEANT4. Focusing on proton energies from 8.5 to 26.5 MeV, we assessed neutron yields, maximum neutron energies, and neutron spectra, finding the QGSP_BIC_AllHP physics list to be the most suitable among GEANT4's recommended options for the studied reactions. The results show distinct yield patterns and energy distributions across targets: ⁷Li and ⁹Be generate higher quasi-monoenergetic neutron energies and yields, while both energies and yields for ¹¹B are lower, attributed to its higher reaction thresholds and more complex excitation structure. The comparison further shows that neutron yields for ⁹Be are generally higher than those for ⁷Li, with a notable increase beyond 16.5 MeV. Target thicknesses were optimized to enhance yield and minimize spectral broadening. These simulations are of particular interest for the ongoing development of a neutron beamline at the 24 MeV CYRCé proton cyclotron at IPHC-Strasbourg. The findings also provide foundational data for future experimental campaigns at the CYRCé facility, contributing to advancements in accelerator-based neutron research and neutron detection systems.