Photoneutron and photofission cross sections for 238U and 232Th using neutron capture gamma rays

Abstract

The photofission and total photoneutron cross section of 238U and 232Th have been measured as a function of energy between 5 and 11 MeV. The photons used were those produced in the neutron capture reaction in the Tangential Beam Port Facility of the University of Virgina Reactor. The capture γ ray sources used were the following; Al, Cr, Co, Cu, Fe, Ni, N, S and Ti. A computer code was used to calculate the spectrum of each capture γ ray beam used in the irradiations. This calculation accounted for the attenuation in the beam and the contribution from neutron capture in A1 and H. A second code iteratively solved for the best fit cross section curve for the experimentally obtained yield data.