PHOTONEUTRON EMISSION FROM Th232, U233, U238, AND Pu239

Abstract

Measurements have been made of the numbers of neutrons emitted by the fissile materials Th232, U233, U238, and Pu239 under irradiation by betatron X-rays of various energies up to 23 Mev. Yield curves and corresponding cross section curves are given for these nuclides. At low X-ray energies it is found that the yield curves differ from those found with non-fissile heavy elements, corresponding to the fact that even at zero X-ray energy the fissile materials suffer (spontaneous) fission.