Nikita Kovrizhnykh

The 237Np+48Ca reaction has been studied at the gas-filled separator DGFRS-2 at the SHE Factory at Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research. We have observed three -decay chains of 282Nh and descendant nuclei 278Rg, 274Mt, 270Bh terminated by spontaneous fission of 266Db. The half-life T of isotopes 282Nh, 278Rg, and 270Bh correspond to the values expected from experimental systematics for odd-Z nuclei, but T for 274Mt exceeds this value by two orders of magnitude. These results are in agreement with those previously measured in Oganessian et al. [Phys. Rev. C 76, 011601(R) (2007); Phys. Rev. C 106, 064306 (2022)]. Such a significant difference in the measured T for 274Mt is observed for the first time for the heaviest nuclei with Z  107. The decay properties of some heavy odd-Z nuclei are compared with the predictions of a cluster model based on a dinuclear system approach and their corresponding decay schemes are proposed. The reaction cross section was measured to be 0.43■(+0.46@-0.25) pb, which is consistent with the expectation for the excitation functions of the 3n channel in 48Ca-induced reactions. The upper cross-section limit of the 4n reaction channel is 0.28 pb.