Abstract
The isotope 261Bh was produced in the reaction 209Bi(54Cr, 2n)261Bh and its \( \alpha\) decay has been remeasured. It was found that it populates by an unhindered transition of \( \approx\) 10 MeV an excited level at E * > 350 keV in the daughter nucleus 257Db . The latter decays by internal transitions either into the isomeric state or the ground state. A somewhat improved half-life value of T1/2 = 11.8+3.9-2.4 ms was obtained for 261Bh . The data support the previous assignment of the \( \alpha\) activities 257Db (1) and 257Db (2) to the isomer and to the ground state, respectively. No evidence for an isomeric state in 261Bh decaying by \( \alpha\) emission was found. Based on the experimental results and theoretical calculations a partial decay scheme of 261Bh including spin and parity assignments of the ground-state and excited levels in the daughter nucleus 257Db populated by the \( \alpha\) decay and succeeding internal transitions have been suggested. 261Bh represents so far the heaviest nucleus for which such an attempt has been made. No spontaneous fission (SF) events that could be attributed to 261Bh were observed, resulting in an SF branching bSF < 0.05 . The measured production cross-section is (64±15) pb at E * = 22 MeV.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
