Spallation-Fission Competition in Heaviest Elements; Helium-Ion-Induced Reactions in Uranium Isotopes

Abstract

A radiochemical study of fission and spallation products produced by bombardment of ${\mathrm{U}}^{233}$, ${\mathrm{U}}^{235}$, and ${\mathrm{U}}^{238}$ with 18-46 Mev helium ions has been made. As in the case of similar studies using isotopes of plutonium as targets, most of the reaction cross section is taken up by fission. Also, the pronounced increase of the total cross section for ($\alpha , \mathrm{xn}$) reactions with increasing mass number of the target that was observed for plutonium targets is observed for uranium targets.