Total Cross Sections for ~(4,6)He + ~(28)Si Reactions Measured at 10-28 MeV/A

摘要

New results on the energy dependence of the total cross section (σ_R) for ~6He scattering on ~(28)Si in the incident energy range 10-28 MeV/A are obtained. The α-particle-production cross sections for the ~(28)Si(~6He,~4He)X channel are measured as well. The secondary beam of ~6He with an intensity of up to 5 * 10~4 particle/s was generated by bombarding a thick beryllium target with ～32-MeV/A~7 Li ions. In the energy region below 17 MeV/A, σ_R increases sharply. The experimental dependences of the total cross sections are compared with the results of σ_R calculations using the double-folding potential within the optical model. The energy dependence of σ_R for ~6He differs from that for the neighboring nuclei, which can be associated with the structural features of the former nucleus. The energy spectra of α particles produced in the ~6He interactions with silicon indicate two mechanisms of their production: transfer reaction and ~6He breakup in the field of the ~(28)Si nucleus.