βdecay of 61 Mn to levels in 61 Fe

A detailed β-decay study of 61Mn is presented, yielding extended information on the level structure of 61Fe. Pure beams were obtained at ISOLDE, CERN, after selective laser ionization and mass separation of fission products from the bombardment of a UCx target by 1.4-GeV protons. The β and γ information was detected by two MiniBall clusters and three Eplastic scintillators. The new 61Mn decay scheme reveals 48γtransitions, distributed over 20 excited states. A comparison to the decay scheme of 59Mn and excited states in 59Fe is made. Shell-model calculations with two different interactions are performed in order to compare the nuclear structure of the two neighboring odd-Airon isotopes. Tentative spin and parities of several excited states in 61Fe are assigned on the basis of β-decay feeding patterns in both 59,61Fe and of results from the theoretical shell-model calculations.status: publishe