Half-Lives of Low-Lying Isomeric States in 169Ta

Two low-lying isomeric states in 169Ta have been identified via 159Tb(16O, 6nγ)169Ta reaction. Their half-lives are measured to be 28 ± 5 ns for the 9/2- level and 17 ± 4 ns for the 5/2- level by using the delayed γ-γ coincidence method. These two isomeric states are considered to be the bandheads with 9/2-[514] and 1/2-[541] configurations, respectively. Possible neutron quasiparticle configuration for the ground state of 169W is discussed.