Fusion-fission of superheavy compound nuclei produced in reactions with heavy ions beyond Ca

¹ FLNR, Joint Institute of Nuclear Research, 141980 Dubna, Russia
² Physikalihes Institute, Universitaet Tuebingen, 72076 Tuebingen, Germany
³ INFN and Dipartamento di Scienze Fisiche dell’Universita di Napoli, Napoli, Italy

Abstract

Total Kinetic Energy - Mass distributions of fission-like fragments for the reactions of ²²Ne, ²⁶Mg, ³⁶S, ⁴⁸Ca, ⁵⁸Fe and ⁶⁴Ni ions with actinides leading to the formation of superheavy compound systems with Z=108-120 at energies near the Coulomb barrier have been measured. Fusion-fission cross sections were estimated from the analysis of mass and total kinetic energy distributions. It was found that the fusion probability drops by three orders of magnitude for the formation of the compound nucleus with Z=120 obtained in the reaction ⁶⁴Ni+²³⁸U compared to the formation of the compound nucleus with Z=112 obtained in the reaction ⁴⁸Ca+²³⁸U at the excitation energy of the compound nucleus of about 45 MeV. From our analysis it turns out that the reaction ⁶⁴Ni+²³⁸U is not suitable for the synthesis of element Z=120.