Neutron-deficient americium isotopes 233,234,235,236Am were produced in the bombardment of multiple thin targets of 233U and 235U with 7.6-10.5 MeV/nucleon 6Li ions. The reaction products were effectively mass-separated using the on-line isotope separator (JAERI-ISOL) coupled to a helium gas-jet transport system. For the first time, the α transition of 235Am was observed, and some improved α-decay data for 233,234,236Am and229Np (α-decay daughter of 233Am) were accumulated. The α-particle energies of 233Am and 235Am were determined to be 6780±17 keV and 6457±14 keV and their half-lives were 3.2±0.8 min and 10.3±0.6 min, respectively. Measured α-decay branching ratios of 235Am and 229Np were (4.0±0.5) × 10-3 and 0.68±0.11, respectively, while the lower limit for α-decay of 233Am was deduced to be 3 × 10-2. Hindrance factors and probable assignments of the levels involved in those α transitions are discussed.
|ジャーナル||Physical Review C - Nuclear Physics|
|出版ステータス||Published - 2004 1月|
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