Multi-particle Photonuclear Reactions behind Giant Dipole Resonance

Abstract

Experimental data on yields of multi-particle photonuclear reactions (involving the emission of up to seven neutrons from the nucleus involved) on 197 Au, 203;205 Tl, and 209 Bi nuclei in the region extending from the giant dipole resonance to an energy of 67.7 MeV are presented. These data are compared with the results of modern theoretical calculations that take into account both the excitation of a giant dipole resonance (GDR) in a nucleus and the photodisintegration of quasideutrons (QD) in it. By and large, experimental data conrm the results of theoretical calculations { that is, only upon taking simultaneously into account both alternative photodisintegration mechanisms (GDR excitation and QD photodisintegration) can one describe these experimental data. The contribution of QD photodisintegration grows with increasing photon energy and neutron multiplicity and becomes dominant for reactions with the emission of not less than ve neutrons from the nucleus being considered.