Isomeric decay studies using a recoil mass separator

Microsecond isomers in the exotic proton-richN=82, 83 nuclei153Yb,153Lu,154Lu and154Hf have been identified byγ-ray spectroscopy following mass analysis of102Pd+245 MeV54Fe reaction products using the Daresbury Recoil Separator. The decays of the isomers, interpreted asπh 11 2/n andπh 11 2/n vf7/2 states, are characterized. The reduced E2 transition rates indicate that half-filling of theπh11/2 subshell occurs just belowZ=71, and results for theN=83 odd-odd isotones are also consistent with this finding.