γ-ray spectroscopy of excited states in 61 30Zn31

The ⁶¹ ₃₀Zn₃₁ isotope has been produced at the Oak Ridge National Laboratory in the fusion-evaporation reaction ⁴⁰Ca(²⁴Mg, 2pn)⁶¹Zn at 104MeV. The experimental set-up allowed γ-rays to be detected in the CLARION Ge detector array in coincidence with the detection of recoiling nuclei in the focal plane at the end of the recoil mass spectrometer. This provides a unique identification of γ-rays belonging to ⁶¹Zn. The excited states have been explored by means of recoil- γγ coincidences, and the resulting decay scheme comprises almost 70 transitions. The data reveal numerous non-yrast states and suggest a revised spin and parity assignment for a previously observed superdeformed band. The resulting decay scheme is compared to predictions from different sets of large-scale shell model calculations.