Fusion-Fission Dynamics of Super-Heavy Element Formation and Decay

Abstract

Abstract. The paper is focused on reaction dynamics of super-heavy nucleus formation and decay at beam energies near the Coulomb barrier. The aim is to review the things we have learned from recent experiments on fusion-fission reactions leading to the formation of compound nuclei with Z ≥ 102 and from their extensive theoretical analysis. Main attention is paid to the dynamics of formation of very heavy compound nuclei taking place in strong competition with the process of fast fission (quasi-fission). The choice of collective degrees of freedom playing a principal role, finding the multi-dimensional driving potential and the corresponding dynamic equation regulating the whole process are discussed. Theoretical predictions are made for synthesis of SH nuclei up to Z=120 in the asymmetric "hot" fusion reactions basing on use of the heavy transactinide targets.

The extension of the Periodic System: superheavy — superneutronic

“…7 in the three-dimensional space of`elongation ± deformation ± mass-asymmetry' used in the calculations. The predictions for the excitation functions of SH element production with Z = 112 ± 118 in 1n ± 5n evaporation channels of the 48 Ca-induced fusion reactions 27,28 made within our approach agree well with the experimental data obtained later. This gives us confidence in receiving rather reliable estimations of the reaction cross sections discussed below.…”

Synthesis of superheavies: State of affairs and outlooks

“…1 in the three-dimensional space of "elongation-deformationmass-asymmetry" used in the calculations. Made within our approach the predictions for the excitation functions of SH element production with Z=112÷118 in 1n÷5n evaporation channels of the 48 Ca induced fusion reactions [14,15] agree well with the later obtained experimental data. This gives us confidence in I).…”

“…The orientation effects are known to play an important role in fusion reactions of statically deformed heavy nuclei [11,14,15]. The fusion probability (formation of CN) was found to be strongly suppressed for more elongated nose-to-nose initial orientations [11].…”