Angular distributions and cross sections of the photoneutron reaction in 9Be in the photon energy region 18–26 MeV

Abstract

The 9Be(γ,n0)8Be and 9Be(γ,n1)8Be reactions were studied in the photon energy region 18 to 26 MeV. The integrated cross section of the (γ,n0) reaction was found to be less than 0.1 MeV mb in this energy region. The integrated cross section for the (γ,n1) reaction in the energy region is 2.4 ± 0.4 MeV mb, which is 10 to 15% of the total photoneutron cross section. The measured angular distributions for the (γ,n1) reaction are consistent with the population of 3/2+ and 5/2+ states of 9Be. These results are consistent with slightly re-interpreted predictions of Majling, Kukulin, and Smirnov.