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

B. Olaizola et al. -- 20 pags., 8 figs., 5 tabs.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.This work was partially supported by the Spanish MINECO through projects FPA2013- 41267-P, FPA2014-57196, FPA2012-32443 and Centro de Excelencia Severo Ochoa Programme (SEV-2012-0249). It was also partly funded by the NuPNET network FATIMA (PRI-PIMNUP-2011-1338). Support by Grupo de Física Nuclear (GFN-UCM) and by the European Union Seventh Framework through ENSAR (contract 262010) is also acknowledged. BO acknowledges funding by the CPAN Consolider (CSD-2007-00042) project. AA and SRL acknowledge funding by the US National Science Foundation under contract PHY- 07-58100. Fast timing electronics were provided by the Fast Timing Collaboration and MASTICON.Peer Reviewe