Alpha particles from the photodisintegration of 9Be in the photon energy region 18 to 26 MeV

Abstract

Alpha particles from the 9Be(γ,n)8Be(16.6) and 9Be(γ,α0)5He reactions were studied in the photon energy region 18 to 26 MeV; the results yielded a combined integrated cross section of 13.1 ± 2 MeV mb and an upper limit on the integrated (γ,α0) cross section of 4.0 MeV mb. This agrees within error with the integrated cross section of Becchi, Meneghetti, Sanzone, and Vitale, 10 ± 2 MeV mb, which would contain about 50% of any contribution from the (γ,α0) reaction. These reactions together with the 9Be(γ,n1)8Be reaction (which has an integrated cross section of 2.4 ± 0.4 MeV mb) are the major reaction channels contributing to the total photoneutron cross section in this energy region. Their sum, 15.5 MeV mb, agrees well with the results of Nathans and Halpern and Hughes, Sambell, Muirhead, and Spicer but disagrees with that of Costa, Pasqualini, Piragino, and Roasio.