Evaluation of the p-11B reaction cross section through a silicon telescope in the 0.3–4.7 MeV range

Abstract

The proton-boron fusion reaction \(^{11}\)B(p,\(\alpha \))\(\alpha \) \(\alpha \) is of significant interest in nuclear physics, with implications in nuclear engineering, medicine, astrophysics, and fusion energy. Despite extensive research, understanding the reaction mechanism and kinematics remains elusive, underscoring the need for more experimental data. This study aims to quantify the p-11B reaction cross section across a proton energy range from 0.34 to 4.73 MeV. A novel experimental setup integrates custom-produced boron-coated targets with a two-stage monolithic silicon telescope for particle detection. The boron targets were fabricated using Pulsed Laser Deposition technique, allowing precise control over the target’s properties. By utilizing a double-stage silicon device, accurate measurements of particle energy spectra were obtained, discriminating \(\alpha \) particles from scattered protons. The experimental campaign used a Van de Graff accelerator as a proton source. Monte Carlo simulations based on the FLUKA code assessed the actual reaction energy of primary protons. This study presents a novel proton energy-dependent cross-section behavior in the energy range from 0.34 to 4.73 MeV, including uncertainties on proton energy and cross-section values, along with detailed \(\alpha \) particle spectra at these energies. Comparison with literature data shows strong agreement for proton energies above the 0.675 MeV resonance peak, up to 3.5 MeV. A significant increase in the cross section close to 4.5 MeV indicates a potential unexplored resonance in this energy range. These findings suggest the need for expanding the energy range of cross-section evaluation and exploring possible resonances, particularly around 5 MeV.