Elastic scattering cross sections for 6Li and 7Li scattering by aluminum, silicon and titanium below 12 MeV at angles of 140 ∘ and 170 ∘

Abstract

Elastic scattering cross sections for 6Li and 7Li scattering by natural aluminum, silicon and titanium have been measured in the energy range of 4–11 MeV. Scattering angles were 140 ∘ and 170 ∘ for 6Li and 140 ∘ for 7Li. The threshold energies above which Rutherford backscattering becomes invalid have been determined. Above this threshold the cross sections decrease rapidly, rendering backscattering analysis impractical. For 7Li scattering by Al and Si the observed threshold values were higher than for 6Li scattering. This behavior was reversed for scattering by Ti. The findings were systematic for both scattering angles. The present cross section and threshold data have been compared with the available literature data. The experimental threshold energies are compared with results obtained by analytical models based on nuclear potential perturbation calculations. For all targets studied, the experimental 6Li threshold energy values exceed the calculations. In the case of 7Li the comparison yields less systematic results.