Deuteron-Model Calculation of the High-Energy Nuclear Photoeffect

Abstract

The high-energy nuclear photoeffect has been calculated according to the deuteron model of Levinger. In this model, the photoprocess occurs when a neutron and a proton which are scattering one another inside the nucleus absorb the energy of the incident photon and escape from the nuclear potential well into the laboratory. The nuclear photoeffect cross section is then obtained by averaging the cross section for the above process over all possible neutron-proton pairs in the nucleus, assuming a nucleon momentum distribution. The electric dipole and quadrupole interactions of the radiation field with the neutron and proton are included, and the magnetic terms are neglected. The averaging over all neutron-proton pairs is performed by means of a random flight formulation of the problem. The analytical work involved may conveniently be done using either a zero-temperature Fermi ground-state nucleon momentum distribution or a Gaussian distribution. Numerical results for the energy and angle distributions of photoneutrons and photoprotons are presented in the case of the Gaussian distribution, for four photon energies between 50 and 125 Mev.