“Complete” high-spin structure of ⁵⁷Co

A comprehensive high-spin decay scheme has been deduced for ⁵⁷Co using the Gammasphere Germanium detector array coupled to the 4π charged-particle detector system Microball. Following the fusion-evaporation reaction of ²⁸Si(³⁶Ar,1α3p)⁵⁷Co at 136 MeV beam energy about 90 excited states have been observed in ⁵⁷Co, which are connected by some 230 γ-ray transitions. The proposed level scheme reaches 16 MeV excitation energy at a spin of 17ħ–18ħ. With its complexity the level scheme of ⁵⁷Co appears to be “complete” up to 1 or 2 MeV above the yrast line. This aspect is further investigated through a comparison of the data with spherical shell-model calculations.