First Experiment at the Super Heavy Element Factory: New Data from the 243Am + 48Ca Reaction.

We presented the results of the series of experiments on the synthesis of Mc isotopes in the ²⁴³Am + ⁴⁸Ca reaction performed at the new separator DGFRS-2 and cyclotron DC280 of the SHE Factory at FLNR JINR. There were registered 110 new ²⁸⁸Mc decay chains, 10 ²⁸⁹Mc chains, and 4 ²⁸⁷Mc chains. Alpha decay of ²⁶⁸Db with an energy of 7.6–8.0 MeV, half-life h and α-branch % was registered for the first time together with a new spontaneously fissioning isotope ²⁶⁴Lr with a half-life of h The measured cross section of the ²⁴³Am(⁴⁸Ca, 3n)²⁸⁸Mc reaction was pb, which is the largest for known superheavy nuclei. A new isotope 286Mc was synthesized with a half-life of 20 ms and an α-particle energy of 10.71 ± 0.02 MeV. Spontaneous fission of ²⁷⁹Rg was first observed in one of the four new decay chains of ²⁸⁷Mc. The reaction excitation function was measured at six ⁴⁸Ca energies in the range of 239–259 MeV, which led to the first observation of the 5n channel with a cross section of 0.5 pb. The decay properties of 20 previously known isotopes have been determined with higher accuracy. [ABSTRACT FROM AUTHOR]