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In many applications, knowing neutron cross sections is fundamental for accurate quantitative evaluations, including (n, cp) reactions that produce protons, deuterons, tritons, and alpha particles. Investigating these mechanisms is crucial for assessing radiation damage in tokamak structural materials [1] (notably Be, Fe, Mo, and W in blankets and divertors) and evaluating delivered doses in advanced radiation therapy like Boron Neutron Capture Therapy (BNCT). Furthermore, in dosimetry, astrophysics, and nuclear fission, key reactions include $^{14}N(n, p)^{14}C$, $^{16}O(n, \alpha)^{13}C$ and $^{35}Cl(n, p)^{35}S$. For the measurement of low-energy charged particles (< 2 MeV), a GEMpix detector in a side-on geometry has been proposed because it could represent a complementary diagnostic with respect to higher-energy charged particles. The new side-on GEMpix [2] has a standard configuration in its amplification and read-out stages (a triple GEM camera read by a Timepix1 Quad), but features a drift region of 12 mm and two side glass windows. In addition, the cathode is removable so that it can be substituted with another one equipped with a vertical target on one side, located at the beginning of the active volume. For the experimental tests performed at the n_TOF facility (CERN), the target was a 5 $\mu$m layer of Lithium Fluoride (LiF) enriched with $^{6}Li$ at 95% deposited on a 400 $\mu$m Alumina sheet. The experiment aimed to study the capability of the new detector to identify and discriminate triton and alpha reaction products from the ($n$, $^{6}Li)$ reaction. Their measurement was tested across different neutron energy ranges from thermal up to 15 MeV, which is of interest for fast neutrons in nuclear fusion. The results presented in this work demonstrate that by defining appropriate track parameters, it is possible to identify the two particle families (alphas and tritons) down to a minimum energy of 0.2 MeV. Furthermore, the background contribution was estimated and characterized by means of FLUKA MC simulations, particularly at higher neutron energies.
[1] M.R. Gilbert et al., Neutron-induced dpa, transmutations, gas production, and helium embrittlement of fusion materials, J. Nucl. Mat. 442, Supp. 1, S755 (2013)
[2] G. Claps, A. Tamburrino, V. De Leo, F. Cordella, D. Pacella, A. Pietropaolo, A. Zerbini, M. A. Vincenti, Side-on GEMpix detector for the measurement of charged particles from neutron induced reactions, 2025 International Conference on Applied Electronics (AE)