Mass distribution and the total fission cross section in the fission of 238U with protons of energies ranging between 13 and 55 MeV

Abstract

The fission of 238U with protons of energy ranging from 13 to 55 MeV was studied radio-chemically. The mass-yield curve was obtained for each of the eleven incident energies, and an analysis was performed, based on the two-mode-fission mechanism. The observed total chain yields were reasonably reproduced by the combination of the three Gaussian curves with partial distortions. The deduced number of neutrons emitted in the fission was found to agree well with the postulated value in the study of the charge distribution systematics. For the three highest incident energies, the formation of the fissile nuclei through a direct process was shown to occur and the analyzing method was discussed. The peak-to-trough ratio and the total fission cross section were obtained from thus-established mass distribution curves.