Nuclear charge distribution in proton-induced fission of 238U

Abstract

Fractional chain yields of 86Rb, 132Te, 134Cs, 136Cs, 140Ba, 148Pm, and 160Tb were determined radiochemically in the fission of 238U induced with 13- to 55-MeV protons. From investigation of the excitation energy dependence of these yield data, a common charge dispersion curve, y = (2πσ 2) − 1 2 exp [ −(Z−Z p) 2 2σ 2 ] , was found valid for all mass chains throughout this energy range. The resulting values of 2σ 2 were found to be 0·97±0·06. The pre-fission neutron emission is also discussed in connection with the fragment mass ratio.