POSSIBILITY OF SYNTHESIZING A SUPERHEAVY NUCLEUS AT THE CENTER OF ISLAND OF STABILITY

摘要

The possibility of synthesizing a doubly magic superheavy nucleus, ~(298)F1_(184), is investigated on the basis of fluctuation-dissipation dynamics. In order to synthesize this nucleus, we must generate more neutron-rich compound nuclei because of the neutron emissions from excited compound nuclei. The compound nucleus ~(304)F1 has two advantages to achieving a high survival probability. First, because of low neutron separation energy and rapid cooling, the shell correction energy recovers quickly. Secondly, owing to neutron emissions, the neutron number in the nucleus approaches that of the double closed shell and the nucleus attains a large fission barrier. Because of these two effects, the survival probability of ~(304)F1 does not decrease until the excitation energy E*= 50 MeV. These properties lead to a rather high evaporation residue cross section. Also, using the dynamical model, we study fission fragment mass distributions from the fission of U and Pu isotopes at low excitation energies. It was found that the shell effect of the potential-energy landscape has a dominant role in determining the mass distribution. The present approach can serve as a basis for more refined analysis.