Nuclear charge distribution in the region of symmetric fission of 238U by protons of energy 20–85 MeV

Independent formation cross sections in the fission of 238U by protons of energy 20–85 MeV were obtained for the nuclides 111Ag, 112Ag, 117In, 115In, 111Pd, and 115Cd. The last three mentioned were estimated on the basis of measurements and isomeric yield data. Charge dispersion curves were constructed and Zp, the most probable charge, determined. The values for (ZA − Zp) lie intermediate between those measured for fission products of higher and lower mass. The number of neutrons emitted was estimated and found to be higher than in asymmetric fission, leading to the conclusion that the former are events arising from higher deposition energies.