Relation of photonuclear reactions to π-meson photoproduction process

Abstract

Neutron-proton pair knocking-out by photons from iron (Fe56) nuclei is studied by measuring induced gamma activity of Mn54 isotope. Experiments are performed in a synchrotron beam at two maximum photon energies, 150 and 650 MeV. It was found that the yield of the reaction under study at the maximum energy of 150 MeV is almost zero, whereas a significant yield of gamma active Mn54 nuclei is measured at the energy of 650 MeV. The cross section of the neutron-proton pair production reaction on Fe56 at an energy of 650 MeV is estimated as 4 · 10−27 cm2.