Nuclear charge dispersion in the fission of 232Th by protons of energy 20–85 MeV

Abstract

232Th was irradiated with protons of energy 20–85 MeV and the independent yields of 130Cs, 132Cs, 134Csm, 134Csg, 136Cs, 138Cs, 86Rb, and the cumulative yields of 137Cs and 138Xe were measured radio-chemically. Charge dispersion curves were constructed at various energies and, as in previous studies, the broadening with increasing energy and shift of the most probable charge towards stability were observed. The most probable charge of a fission fragment of a given mass number lies closer to the line of β-stability in the case of thorium fission than in uranium. Detailed calculations in an attempt to correlate the experimental data with equal charge displacement (e.c.d.) and unchanged charge displacement (u.c.d.) charge distribution postulates were attempted. The results are not conclusive, lying in between the two, but favoring u.c.d. at the higher energies.