Using a proportional counter, measurements have been made of the fission fragment angular distributions, kinetic energy spectra, and the total fission cross sections for the reactions C+Au, O+Au, C+Bi, and O+Bi at 10.5 Mev per nucleon bombarding energies and for the C+Bi reaction at energies from 72 Mev to 126 Mev. The results show the kinetic energy spectra to be independent of the excitation of the compound system and the most probable fragment kinetic energies to be 75±3 Mev and 81±3 Mev for the gold and bismuth target reactions, respectively. In all cases the fission cross sections are found to be only 60-80% of the estimated compound-nucleus formation cross sections. The angular distributions are fitted by the theory of Halpern and Strutinski, and an attempt is made to determine some of the qualitative features of these heavy-ion reactions.

• Received 26 July 1960

DOI:https://doi.org/10.1103/PhysRev.120.1768