Neutrons fromBe9(α,n)Reaction forEαbetween 6 and 10 MeV

Abstract

Absolute differential cross sections have been measured as a function of angle and $\alpha$ bombarding energy for the reaction ${}_{}{}^9{}_{}{}^{}\mathrm{Be}(\alpha ,n){}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ leaving ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ in its ground, first excited, and second excited states. The angular distribution for the ground-state (0+ state) transition changed from a fore-aft peaking at $E_{\alpha }=6.8\mathrm{}$ MeV to a three-peaked angular distribution at $E_{\alpha }=9.9\mathrm{}$ MeV. Similar behavior was observed for the second-excited-state transition (0+). The angular distribution for the first-excited-state transition (2+) displayed fore-aft peaking and was not sensitive to bombarding energy. A strong, low-energy component, present at forward angles at all bombarding energies, can be accounted for by three- and four-body breakup reactions.