Decay of Plutonium isotopes via spontaneous and heavy-ion induced fission paths

Abstract Based on the collective clusterization approach, we have extended our earlier study on α -decay, exotic cluster-decay, and heavy particle radioactivity, to the phenomenon of spontaneous fission (SF) in the ground-state (g.s.) decays of even mass 234−246 Pu parents. The calculations for the SF half-lives of these Pu-isotopes have been made within the framework of preformed cluster model (PCM), both for spherical as well as β 2 -deformed choices of shapes, and a comparison is made with the relevant available experimental data, which prefer spherical shapes. The importance of the orientation degree of freedom (hot compact or cold elongated configurations) is also explored. Next, in order to look for the exclusive role of heavy-ion induced fission, the dynamics of 6 He + 238 U reaction forming 244 Pu ⁎ is studied over the center of mass energy range of E c . m . = 15.0 – 28.8 MeV , using the dynamical cluster-decay model (DCM), an extension of the PCM with temperature T- and angular momentum l -effects included. The β 2 -deformed fragments of 244 Pu ⁎ in the mass range A 2 = 106 – 113 (plus their complementary heavy fragments), corresponding to asymmetric fission peaks, are found contributing towards the fission cross-section. Finally, the potential energy surfaces and barrier modification effects are presented for the relative comparison of spontaneous and the heavy-ion induced fission processes. Both are found to behave similar with respect to the probable emission of fragments and hence point out to the shell closure property of the decay fragments.