ReactionBe9(α,n)C12from 1.7 to 6.4 MeV

Abstract

The 0° excitation functions for the reaction Be9(α,n)C12 leading to the ground and first excited states of C12 were measured between 1.69- and 6.44-MeV bombarding energy, while those for the second- and third-excited-state neutron groups were measured above 2.94- and 5.94-MeV bombarding energy, respectively. Angular distributions of the ground state and first two excited-state neutron groups were measured at 17 bombarding energies between 3.21 and 6.44 MeV, and for the third-excited-state neutron group they were measured at 6.24- and 6.44-MeV bombarding energy. The magnitude of the cross sections for the ground- and first-excited-state neutron groups agrees well with the larger of the two sets of conflicting magnitudes reported in the literature. Double-differential cross sections of the continuum of low-energy neutrons were measured as a function of angle and neutron energy for 10 bombarding energies ranging from 4.86 to 6.44 MeV. The features of the continuum are consistent with the sequential decay Be9+α→Be*9+α′→Be8+n+α′, proceeding through the 1.67-, 2.43-, and 3.04-MeV excited states in Be9. The ratio of the populations of the first and second excited states in the Be9(α,n)C12 reaction was determined at 16 bombarding energies between 3.99 and 6.44 MeV.