Search for Weak Side Branches in the Electromagnetic Decay Paths of the 6526-keV 10+ Isomer in 54Fe

High-spin nuclear isomers in N approximate to Z nuclei between doubly magic Ca-40 and Ni-56 provide an excellent testing ground for the nuclear shell model and questions related to isospin symmetry breaking in the vicinity of the proton drip line. The purpose of the present study is to investigate the possibility of weak electromagnetic decay branches along the decay paths of the 6526-keV 10(+) isomer in Fe-54. The isomer was strongly populated by means of the fusion-evaporation reaction Mg-24(Ar-36,alpha 2p)Fe-54m. The Gammasphere array was used to detect gamma-ray cascades emitted from the isomeric state. By means of gamma gamma gamma coincidences, weak non-yrast decay branches can be discriminated, with the isomer's half-life confirmed at T-1/2=363(4) ns. The yrast 6(1)(+) -> 2(1)(+) E4 cross-over transition was interrogated. The observations are compared with shell-model calculations.

Automated summary

This study investigates the possibility of weak electromagnetic decay branches along the decay paths of high-spin nuclear isomers in Fe-54. The Gammasphere array is used to detect gamma-ray cascades emitted from the isomeric state, allowing for discrimination of weak non-yrast decay branches. The observations are compared with shell-model calculations.