The nuclide Db262 was produced in the Cm248(F19,5n)Db262 reaction at beam energies of 103.1 and 97.4 MeV. Decay properties of Db262 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 76 chains were assigned to Db262 and its α-decay daughter nuclide Lr258. No correlated decay chain was observed for 263Db produced in the Cm248(F19,4n)263Db reaction and its daughter 259Lr. The half-lives of Db262 and Lr258 were measured to be T12=33.8-3.5+4.4 and 3.54-0.36+0.46s, respectively, and they confirmed the literature data. The α-particle energy (Eα) and intensity (Iα) of Db262 were revised to Eα = 8.46 ± 0.04 MeV (Iα = 70 ± 5%) and Eα = 8.68 ± 0.03 MeV (Iα = 30 ± 5%). The SF activity with T1/2 = 30.2 ± 6.1 s was assigned to Db262, and the SF branch of Db262 was determined to be bSF = 52 ± 4%. From an observation of two SF decays which correlated to the α decay of Db262, an electron capture (EC) decay with bEC = 2.6 ± 1.8% was suggested in Lr258. The production cross sections for the Cm248(F19,5n)Db262 reaction were determined to be 2.1 ± 0.7 nb at 103.1 MeV and 0.23-0.11+0.18nb at 97.4 MeV, whereas, those for the Cm248(F19,4n)263Db reaction were the upper limits of ≤0.064 nb at 103.1 MeV and ≤0.13 nb at 97.4 MeV. These cross sections are discussed by comparing with the literature data as well as the theoretical prediction.
ASJC Scopus subject areas
- Nuclear and High Energy Physics