First experiment at the Super Heavy Element Factory: High cross section of 288Mc in the 243Am+48Ca reaction and identification of the new isotope 264Lr

We present results of the first experiment aimed at the synthesis of Mc isotopes in the 243Am + 48Ca reaction performed at the new gas-filled separator DGFRS-2 online to the new cyclotron DC280 at the Super Heavy Element Factory at JINR. Fifty-five new decay chains of 288Mc and six chains assigned to 289Mc were detected. The alpha decay of 268Db with an energy of 7.6-8.0 MeV, half-life of 16+6-4 h, and a branch of 55+20 -15% was registered for the first time, and a new spontaneously fissioning isotope 264Lr with a half-life of 4.9+2.1 -1.3 h was identified. The cross section for the 243Am(48Ca, 3n) 288Mc reaction was measured to be 17.1+6.3 -4.7 pb, which is the largest value for the known superheavy nuclei at the island of stability.

Automated summary

Results of the first experiment on the synthesis of Mc isotopes were presented, where 55 new decay chains and several new isotopes were detected. The alpha decay of 268Db and the identification of 264Lr were reported for the first time.