Reinvestigation of the decay properties of Bh261,262 at the gas-filled recoil separator SHANS2

The isotopes 261,262Bh were reinvestigated by using the cold fusion reaction ⁵⁴Cr+²⁰⁹Bi. The evaporation residues were separated by the gas-filled recoil separator SHANS2 (Spectrometer for Heavy Atoms and Nuclear Structure-2) and identified by means of the recoil-α-correlation method. The α-decay properties of 261,262Bh were measured and the results are consistent with the previously reported values. Based on the measured half-lives, the existence of two distinct states of ²⁶²Bh was confirmed, whereas ²⁶¹Bh lacked any isomer with α-decay properties. Two spontaneous fission events potentially from ²⁶²Bh and/or ²⁶¹Bh were detected and the production cross sections at beam energies of 264.1 and 270.4 MeV were obtained.