Production of Bh 266 in the Cm 248 (Na 23,5n) Bh 266 reaction and its decay properties

Abstract

The nuclide 266Bh was produced in the 248Cm(23Na,5n)266Bh reaction at beam energies of 125.9, 130.6, and 135.3 MeV. Decay properties of 266Bh were investigated with a rotating wheel apparatus for α and spontaneous fission (SF) spectrometry under low background conditions attained by a gas-jet transport system coupled to the RIKEN gas-filled recoil ion separator. Based on genetically correlated α−α and α-SF decay chains, a total of 23 chains were assigned to 266Bh and its daughter nuclide 262Db and granddaughter 258Lr. The half-life of 266Bh was measured to be T1/2=10.0+2.6−1.7s which is an order of magnitude longer than the literature data. The α-particle energies of 266Bh disperse widely in the range of Eα=8.62–9.40MeV. The maximum production cross section for the 248Cm(23Na,5n)266Bh reaction was determined to be σ=57±14 pb at 130.6 MeV, whereas the upper limit for the 248Cm(23Na,4n)267Bh reaction was σ≤14 pb at 121.2 MeV. These cross sections are discussed by comparing with the literature data as well as the theoretical calculations.