A study of the Be 9(p, α)Li 6 reaction from 3.5 to 12.5 MeV

Abstract

Angular distributions and excitation curves for the Be 9(p, α 0)Li 6 and Be 9(p, α 1)Li 6∗ (2.18 MeV) reactions have been measured for proton bombarding energies from 3.50 to 12.50 MeV. Total cross sections, as well as 90° (lab) yields, for α 0 and α 1 are monotonically decreasing functions of energy and the angular distributions show very little change with energy. These data suggest that the reaction is predominantly a direct process over the energy interval studied. No prominent resonance behaviour is observed in the energy interval corresponding to excitation energies in B 10 from 9.3 to 17.8 MeV. In order to perform a consistent distorted-wave Born approximation (DWBA) calculation of the reaction, elastic scattering experiments in the entrance and exit channels were performed. At the same time data were obtained on several other reactions, namely Be 9(p, d)Be 8, Be 9(p, p′)Be 9∗ (2.43 MeV), Li 6(α, α′)Li 6∗ (2.18 MeV) and Li 6(α, d)Be 8. Optical model parameters for the zero-range DWBA calculation of Be 9(p, α)Li 6 were obtained by analysing the elastic scattering data. Results of the calculation based on the triton pick-up process give fairly good agreement with the data for α 0, but not for α 1. These results are compared to plane wave calculations. The possibility of interpreting the data in terms of exchange processes is also discussed, as well as the applicability of the DWBA calculation to this reaction.