Superheavy nuclei from 48Ca-induced reactions

AbstractThe discovery and investigation of the new region of superheavy nuclei at the DGFRS separator based on fusion reactions of 48Ca with 238U–249Cf target nuclei are reviewed. The production cross sections and summaries of the decay properties, including the results of the posterior experiments performed at the SHIP, BGS, and TASCA separators, as well as at the chemistry setups, are discussed and compared with the theoretical calculations and the systematic trends in the α-decay and spontaneous fission properties. The properties of the new nuclei, isotopes of elements 112–118, and their decay products demonstrate significant increases in the stability of the heaviest nuclei with increasing neutron number and closer approach to magic number N=184

Simulation of angular and energy distributions for heavy evaporation residues using statistical model approximations and TRIM code

A Monte Carlo approach has been developed for simulations of the angular and energy distributions for heavy evaporation residues (ER) produced in heavy ion fusion-evaporation reactions. The approach uses statistical model approximations of the HIVAP code for the calculations of initial angular and energy distributions inside a target, which are determined by neutron evaporation from an excited compound nucleus. Further step in the simulation of transmission of ER heavy atoms through a target layer is performed with the TRIM code that gives final angle and energy distributions at the exit from the target. Both the simulations (neutron evaporation and transmission through solid media) have been separately considered and good agreement has been obtained between the results of simulations and available experimental data. Some applications of the approach have been also considered

Discovery of the New Element Z=117 and Confirmation of 115

The discovery of the new chemical element with atomic number Z=117 is presented. The isotopes 293 117 and 294117 were produced in fusion reactions between 48Ca and 249Bk. The 249Bk was produced in the High Flux Isotope Reactor and chemically separated at Oak Ridge. Decay chains involving eleven new nuclei were identified by means of the Dubna Gas-Filled Recoil Separator. The measured decay properties show a strong rise of stability for superheavy nuclei toward N=184.The reaction 243Am+48Ca was studied at three energies. Twenty one decay chains of 288115 and one decay chain of 289115 were observed to confirm the earlier discoveries of Z=115 and 117

Discovery of elements 113 - 118

Review of discovery and investigation of isotopes of elements 113-118 produced in the reactions of 48 Ca with target nuclei 238U-249Cf is presented. The synthesis of the heaviest nuclei, their summary decay properties, and methods of identification are discussed. The radioactive properties of the new nuclei give evidence of the significant increase of the stability of the heavy nuclei with rise of their neutron number and approaching magic number N=184