Transitions in the fission mass distributions of the fermium isotopes

Abstract

Using a liquid-drop-model fission path and the two-centre shell model, the authors calculated static fission mass yields for 253Fm(n,f), 254Fm(sf), 255Fm(n,f), 256Fm(sf), 257Fm(n,f), 258Fm(sf), 259Fm(n,f) and 260Fm(sf). For a particular choice of the length of the fissioning nucleus, the change from asymmetric to symmetric distributions and the gross features of the mass yield curves are reproduced. They predict highly asymmetric events that should be seen primarily in the thermal-neutron-induced fission of the lighter isotopes mentioned.