Description: Radiochemical studies of the fast neutron fission of U/sup 235/ and U/sup 238/ have been made in the mass region beyond mass 143 with two neutron energy distributions. These studies provide measurements of the relative fission yields of several chains in the rare earth group in fission of U/sup 235/ and U/sup 238/ caused by neutrons with an energy distribution very close to unmoderated fission neutrons and by neutrons with an energy distribution peaked at 8 Mev. The increased contribution of very asymmetric modes of fission as the energy of the compound nucleus is increased is clearly shown by the results. In the fission of U/sup 238/ the yield at mass 161 is increased 2.9 times at the higher neutron energy. No previous measurements have been published on radiochemical studies of the fission of U/sup 238/at these neutron energies beyond mass 144 except at mass 156 for the lower neutron energy. (auth)
Date: June 1, 1958
Creator: Bunney, L. R.; Scadden, E. M.; Abriam, J. O. & Ballou, N. E.
Partner: UNT Libraries Government Documents Department