Nuclear charge distribution in fission: Independent yields of 139Ba and 140Ba from thermal-neutron induced fission of 233U

Abstract

Independent yields of 139Ba and 140Ba have been measured from thermal-neutron induced fission of 233U. These nuclides were quickly separated from their cesium precursors and purified radiochemically. Independent yields were calculated from a knowledge of the activities of the nuclides as a function of separation time and the previously measured xenon fractional cumulative yields. The yields, expressed as fractional independent yields, are 0·084±0·007 and 0·27·0·04 for 139Ba and 140Ba, respectively. The relation between cumulative yields of 139Cs, 140Cs, 139Xe and 140Xe is essentially the same for 233U as for 235U. An odd-even effect is noted and for the A = 139 chain this effect may be more important than the 83-neutron effect.