Identification of the new isotope 107265Bh by α correlated decay chains

The experimental set-up, methods and results on the synthesis and identification of the new isotope 107265Bh are presented. The new isotope was produced by the complete fusion-evaporation reaction of 243Am with 135 MeV 26Mg bombardment at the Sector Focus Cyclotron of Heavy Ion Research Facility Lanzhou. The reaction products were transported and collected using helium-jet technique and a set of rotating wheel system. the identification of the new isotope was made by observing of correlated α-particle decays chain between the new isotope 265Bh and its 261Db and 257Lr daughters. A total of 8 correlated decay events of 265Bh and 4 decay events of 264Bh were observed. The new nuclide 265Bh has a half-life of 0.94-0.31+0.70s and decays by alpha-particle emission with decay energy of Eα=(9.24 ± 0.05) MeV. The half-life and α decay energy of 265Bh from this experiment are consistent with theoretical predictions. (authors)