Cross sections for the 16O(γ, 2n), 19F(γ, 2pn), 27Al(γ, 2pn), 51V(γ, α) and 51V(γ, α3n) reactions to 300 MeV

Abstract

Yield and cross section results have been obtained for some photonuclear reactions in 16O, 19F, 27Al and 51V targets by measuring the radioactivities of the product nuclei in samples that had been irradiated with bremsstrahlung in the 20–300 MeV energy range. The reactions studied were 16O(γ, 2n), 19F(γ, 2pn), 27Al(γ, 2pn), 51V(γ, α) and 51V(γ, α3n). The cross sections at energies above 150 MeV have been interpreted in terms of the contributions from various reaction mechanisms. The reactions in O, F and Al generally have important contributions from both quasi-deuteron and pion emission processes. In the 51V reactions, the additional pion reabsorption mechanism also makes important contributions. The reaction cross sections at energies below 150 MeV are used to determine the total cross sections for photon absorption at energies above the giant-resonance region and below 150 MeV. The resulting total cross sections are generally consistent with those determined from neutron-counting experiments.