Measurement of Proton-induced Reactions on Lithium at Ultra-low Energies

Nuclear reactions involving lithium isotopes are important for Big Bang nucleosynthesis and for explaining the depletion of lithium observed in stars. In particular, the \(^{6}\mathrm {Li}(p,\alpha )^{3}\mathrm {He}\) and \(^{7}\mathrm {Li}(p,\alpha )^{4}\mathrm {He}\) reactions play a significant role in the formation and destruction of light nuclei in astrophysical environments. Experimental data at energies below 20 keV are scarce due to the strong influence of electron screening in metallic targets. To investigate this region, measurements were performed at the Ultra High Vacuum accelerator facility of the University of Szczecin using a magnesium–lithium alloy target (55\(\%\) Mg, 45\(\%\) Li). Thick target yields were measured for proton beam energies between 13 and 26 keV with currents up to 1 mA. From these data, a high screening energy of \(U_e= 3.9\pm 0.6\) keV was determined. For comparison, the \(^{2}\mathrm {H}(d,p)^{3}\mathrm {H}\) reaction was also studied on the same target, giving \(U_e = 1.5 \pm 0.19\) keV. These results indicate that MgLi alloys provide exceptionally strong screening and are promising for future low-energy fusion studies. Abstract Published by the Jagiellonian University 2026 authors