DISTRIBUTION OF NUCLEAR CHARGE IN THE PROTON-INDUCED FISSION OF Th232

Abstract

The cross sections for the independent formation of I¹³⁰, I¹³¹, Te¹³¹, I¹³², and I¹³⁴ and for the cumulative formation of Te¹³², I¹³³, and I¹³⁵ in the proton-induced fission of Th²³² have been measured at nine proton energies between 8 and 87 Mev. From these data and from published total chain yield data, charge distribution curves have been obtained. These are compared with published charge distribution curves for uranium fission at energies up to 480 Mev and together they show a shift of the most probable fission product charge toward stability and a widening of the distribution with increasing bombarding energy. These phenomena are interpreted in terms of current models for nuclear reactions.