Beta decay of 66Mn to the N = 40 nucleus 66Fe

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 β- 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 21+ state and four other states of 66Fe were measured using the advanced time-delayed βγγ(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.