Fission of 210Po

Abstract

The excitation functions of the reactions 206Pb(α, f) and 209Bi(p, f) and the anisotropy parameters characterizing, at various excitation energies, the angular distributions of fragments emitted in both reactions are analysed. In the analysis of the excitation functions the angular momentum of the fissioning nucleus is explicitly taken into account. In the calculation of the competing neutron decay width the influence of shell effects on the level density of 209Po has been considered. The effective fission threshold of 210Po (fission threshold plus pairing at the saddle point) is found to be ≈ 21.95 MeV, corresponding to a fissility parameter x ≈ 0.72, a value about 2 % higher than the one recently proposed by Myers and Swiatecki. The ratio I rig/ I eff at the saddle point seems to be about 15 % higher than. the one predicted by the liquid-drop-model calculations of Cohen and Swiatecki.