Neutron-rich nuclei in the region of $Z\approx 28$ and $N\approx 40$ demonstrate a noticeable departure from traditional mean-field nuclear properties through shell evolution effects, display variations in deformation and shape coexistence, and may fall along astrophysical neutron-capture nucleosynthesis pathways. Spectroscopic data on these isotopes provide insight into open questions in low-energy nuclear science, and are becoming more readily available at modern radioactive ion beam facilities. We present the study of the ${}^{71}\mathrm{Fe}\to {}^{71}\mathrm{Co} \beta$ decay, performed using the technique of total absorption spectroscopy. Extracted $\beta$-strength distributions are compared to shell-model calculations to interpret the structure of low-lying levels in ${}^{71}\mathrm{Co}$ and indicate the possibility of shape coexistence. The calculations underestimate the amount of feeding observed at higher excitation energies (and particularly above the neutron separation energy), similarly to some neighboring nuclei in which $\beta$-delayed neutron emission and $\gamma$ decay have been observed to compete. This effect could exert influence on the $\beta$-delayed neutron probability and thus the progression of r-process nucleosynthesis, which is sensitive to such properties.

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• Beta decay
• Electromagnetic transitions
• Energy levels
• Nuclear decay
• Nuclear structure & decays
• 59 ≤ A ≤ 89
• Radiation detectors
• Radioactive beams
• Shell model
• Spectrometers & spectroscopic techniques