Sub-barrier capture with quantum diffusion approach: actinide-based reactions

With the quantum diffusion approach the behavior of capture cross sections and mean-square angular momenta of captured systems are revealed in the reactions with deformed nuclei at subbarrier energies. The calculated results are in a good agreement with existing experimental data. With decreasing bombarding energy under the barrier the external turning point of the nucleusnucleus potential leaves the region of short-range nuclear interaction and action of friction. Because of this change of the regime of interaction, an unexpected enhancement of the capture cross section is expected at bombarding energies far below the Coulomb barrier. This effect is shown its worth in the dependence of mean-square angular momentum of captured system on the bombarding energy. From the comparison of calculated and experimental capture cross sections, the importance of quasifission near the entrance channel is shown for the actinide-based reactions leading to superheavy nuclei.Comment: 11 pages, 16 figures, Regular Articl

Two-Step Model of Fusion for Synthesis of Superheavy Elements

A new model is proposed for fusion mechanisms of massive nuclear systems where so-called fusion hindrance exists. The model describes two-body collision processes in an approaching phase and shape evolutions of an amalgamated system into the compound nucleus formation. It is applied to $^{48}$Ca-induced reactions and is found to reproduce the experimental fusion cross sections extremely well, without any free parameter. Combined with the statistical decay theory, residue cross sections for the superheavy elements can be readily calculated. Examples are given.Comment: 4 pages, 4 figure

Spin distribution measurement for 64Ni + 100Mo at near and above barrier energies

Spin distribution measurements were performed for the reaction 64Ni + 100Mo at three beam energies ranging from 230 to 260 MeV. Compound nucleus (CN) spin distributions were obtained channel selective for each evaporation residue populated by the de-excitation cascade. A comparison of the spin distribution at different beam energies indicates that its slope becomes steeper and steeper with increasing beam energy. This change in slope of the spin distribution is mainly due to the onset of fission competition with particle evaporation at higher beam energies

Mass distributions for quasifission processes in superheavy compositesystems with Z=108-120

This paper presents the study of mass-energy distributions of quasifission fragments obtained in the reactions 36S, 48Ca, 64Ni+238U at energies below and above the Coulomb barrier. To describe the quasifission mass distribution the simple model has been proposed. This model is based on the driving potential of the system and time dependent mass drift. This procedure allows to estimate QF time scale from the measured mass distributions

Mass distributions for quasifission processes in superheavy compositesystems with Z=108-120

This paper presents the study of mass-energy distributions of quasifission fragments obtained in the reactions 36S, 48Ca, 64Ni+238U at energies below and above the Coulomb barrier. To describe the quasifission mass distribution the simple model has been proposed. This model is based on the driving potential of the system and time dependent mass drift. This procedure allows to estimate QF time scale from the measured mass distributions

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

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

Fission of heavy and superheavy nuclei at low excitation energies

This paper studies comprehensive research through qualitative interviews conducted in Malaysia with SME heads and students about their representations of Information and Communication Technology