High-K multi-quasiparticle states in 254No

We report results from an experiment on the decay of the high-K isomers in 254No. We have been able to establish the decay from the known high-lying four-quasiparticle isomer, which we assign as a Kπ = 16+ state at an excitation energy of Ex = 2.928 (3) MeV. The decay of this state passes through a rotational band based on a previously unobserved state at Ex = 2.012 (2) MeV, which we suggest is based on a two-quasineutron configuration with Kπ = 10+. This state in turn decays to a rotational band based on the known Kπ = 8- isomer, which we infer must also have a two quasineutron configuration. We are able to assign many new gamma-rays associated with the decay of the Kπ = 8- isomer, including the identification of a highly K-forbidden Δ K = 8 E1 transition to the ground-state band. These results provide valuable new information on the orbitals close to the Fermi surface, pairing correlations, deformation and rotational response, and K-conservation in nuclei of the deformed trans-fermium region. © 2010 Elsevier B.V.