Narrow Results

Employing Coulomb and proximity potentials, cluster-decay half-lives ($T_{1/2}^{c,\mathrm{\text{th}}}(s)$) of even–even nuclei had been calculated and, the obtained results are compared with the experimental ones. To investigate cluster radioactivity in superheavy nuclei (SHN), we determine the required disintegration energies ($Q_c$-values) utilizing periodic-orbit theory within microscopic-macroscopic formalism and hence, predict the logarithmic values of $T_{1/2}^{c,\mathrm{\text{th}}}(s)$ for even–even SHN with $Z=122$, 124 and 126. Among various isotopes of daughter nuclei, products produced with minimum value of Gibbs free energy are chosen for our investigation. Moreover, study of the branching ratios would make us to find the dominant mode of decay among $\alpha$-decay, spontaneous fission (SF) and cluster-decay in these SHN. Mostly, the emissions of Kr-, Sr-, Zr- and Mo-clusters from these superheavy nuclei are found to be the dominant modes of decay which can be attributed to strong shell effects in the neighborhood of $Z=82$ region. Our results are in agreement with those obtained using UDL method except for few cases. We believe that this work can play a significant role in the study of decay properties of superheavy nuclei.

Results of experiments on the synthesis of superheavy nuclei in ⁴⁸Ca-induced reactions are presented. The experiments were carried out at the Flerov Laboratory of Nuclear Reactions (FLNR) Dubna heavy ion cyclotron U400 in the framework of a large collaboration: FLNR ( JINR, Dubna, Russia), IAR (Dimitrovgrad, Russia), LLNL (Livermore, USA), ORNL (Oak-Ridge, USA).

Enriched isotopes of U ÷ Cf were used as targets. In the reactions studied in 2000 — 2010, decays of the heaviest isotopes of Rf ÷ Cn and isotopes of six new elements 113 ÷ 118 were observed.

Attempts to find superheavy elements in Nature started in the middle of sixties when predictions of the possible existence of longliving nuclei in the far transuranium region have been made. During following 15 years hundreds of geological samples, their processing products and probes of meteorites were studied. In all experiments only upper limits of the superheavy element concentration in the studied samples have been determined.