Abstract
New experimental measurements of the total reaction cross sections for the 6 He + nat Si and 9 Li + nat Si processes in the energy range of 5 to 40 A MeV are presented. A modified transmission method based on high-efficiency detection of prompt n–γ radiation has been used in the experiment. A bump is observed for the first time in the energy dependence σ R ( E ) at E ∼ 10–30 A MeV for the 9 Li + nat Si reaction, and existence of the bump in σ R ( E ) at E ∼ 10–20 A MeV first observed in the standard transmission experiments is experimentally confirmed for the 6 He + nat Si reaction. Theoretical analysis of the measured 6 He + nat Si and 9 Li + nat Si reaction cross sections is performed within the microscopic double folding model. Disagreement is observed between the experimental and theoretical cross sections in the region of the bump at the energies of 10 to 20 A MeV, which requires further study.