Identification of the isomer in neutron-rich W

Shizuma, Toshiyuki; Hayakawa, Takehito; Mitarai, Shiro*; Morikawa, Tsuneyasu*; Ishii, Tetsuro  

Excited states in neutron-rich W have been populated via deep inelastic collisions of a 630-MeV Se beam on a W target. Projectile-like fragments were measured by an annular Si detector for reaction channel selection. Delayed rays from target residues were detected by means of the so-called recoil shadow technique. A new isomer at 411 keV, based on the [615] Nilsson configuration, has been identified with the half-life of 1.56(28) s. The decay rates of the isomers are discussed in terms of the quantum number by comparison with the systematics from the neighboring nuclei.