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

Abstract

The nuclide Bh266 was produced in the Cm248(Na23,5n)Bh266 reaction at beam energies of 125.9, 130.6, and 135.3 MeV. Decay properties of Bh266 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 Bh266 and its daughter nuclide Db262 and granddaughter Lr258. The half-life of Bh266 was measured to be T1/122=10.0-1.7+2.6s which is an order of magnitude longer than the literature data. The α-particle energies of Bh266 disperse widely in the range of Eα=8.62-9.40MeV. The maximum production cross section for the Cm248(Na23,5n)Bh266 reaction was determined to be σ=57±14 pb at 130.6 MeV, whereas the upper limit for the Cm248(Na23,4n)Bh267 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.