Beta decay of $^{66}$Mn to the $N = 40$ nucleus $^{66}$Fe

The low energy structure of 66Fe was studied by means of γ- and fast-timing spectroscopy at the ISOLDE/CERN facility. The level scheme of 66Fe populated following the ${\beta }^{-}$ decay of 66Mn was established. It confirms and further expands the level scheme from recent publications. The β-delayed neutron emission branch was measured and γ rays in 65Fe were observed following the β–n decay for the first time. The half lives of the ${2}_{1}^{+}$ state and four other states of 66Fe were measured using the advanced time-delayed $\beta \gamma \gamma $(t) method. These results are compared with large-scale shell-model calculations based on the Lenzi–Nowacki–Poves–Sieja interaction. The β-decay of 66Mn to 66Fe has been calculated as well, and log(ft) values derived. Spin and parity assignments are proposed based on the experimental information and the new calculations.The low energy structure of 66Fe was studied by means of γ- and fast-timing spectroscopy at the ISOLDE/CERN facility. The level scheme of 66Fe populated following the decay of 66Mn was established. It confirms and further expands the level scheme from recent publications. The β-delayed neutron emission branch was measured and γ rays in 65Fe were observed following the β–n decay for the first time. The half lives of the state and four other states of 66Fe were measured using the advanced time-delayed (t) method. These results are compared with large-scale shell-model calculations based on the Lenzi–Nowacki–Poves–Sieja interaction. The β-decay of 66Mn to 66Fe has been calculated as well, and log(ft) values derived. Spin and parity assignments are proposed based on the experimental information and the new calculations