High eff. structure study of ⁷⁷Ge nuclei from ⁷⁷Ga β-decay

Medium mass Ge nuclei exhibits interesting structural features like shape co-existence and tri-axial deformation in low-lying states which makes it an interesting case both from nuclear structure as well as astrophysical point of view. In this measurement, pure ⁷⁷Cu beam was developed at the Holifield Radioactive Ion Beam facility of Oak Ridge National Lab and detailed β-decay studies of A = 77 decay chain was performed to understand the structure of corresponding daughter nuclei. Data on γ ray emission following β-decay, including βγ and γγ coincidences were recorded, and the gated γγ spectra were analyzed to identify the statistically significant coincidences in cascades. The proposed decay scheme of ⁷⁷Ge nuclei contains a total of 39 energy levels occupying up to 3.2 MeV with the placement of 67 γ rays. Due to the purity of beam and high efficiency four clover HPGe detector used, this work has been able to significantly increase both the number of energy levels and transitions. Finally, shell model-calculations are used for comparison to the observed level density.