Fission modes in fermium isotopes with Brownian shape-motion model

Abstract

Fission-fragment mass and total-kinetic-energy distributions following fission of the fermium isotopes 256,258,260 Fm at low excitation energy have been calculated using the Brownian shape-motion model. A transition from asymmetric fission in 256 Fm to symmetric fission in 258 Fm is obtained. The total-kinetic-energy distributions for the three isotopes show radically different behaviour due to varying contributions from different fission modes, with a double-humped distribution for 258 Fm.