Study of the Cf249-251+Ca-48 reactions: recent results and outlook

Experiment aiming at the synthesis of heavy isotopes of Z=118 (Og) using beam of Ca-48 and a target of Cf249-251 was undertaken in October 2015 - April 2016 employing the Dubna Gas-Filled Recoil Separator (FLNR JINR). The target of mixed isotopes of Cf249-251 (50.7% of Cf-249, 12.9% of Cf-250, and 36.4% of Cf-25) was irradiated by Ca-48 ions at two beam energies of 252 and 258 MeV with the corresponding accumulated beam doses of 1.6 x 10(19) and 1.1x10(19). A single event observed at lower beam energy was assigned to the isotope (294)Og, the product of the reaction Cf-249(Ca-48, 3n); its decay pattern and the observed radioactive properties of the nuclides in the decay chain reproduce in full those observed for (294)Og in our earlier experiments of 2002-2005 and 2012. At higher beam energy we observed no decay chains that could be attributed to the isotopes of Og. The possibility of renewal of this experiment in the future is discussed.