Configurations of the low-lying states in Eu 146

The low-lying states of Eu146 populated in the decay of the 9+ isomer were studied. The γ-ray intensities were reanalyzed employing germanium detectors, and the lifetimes of the 61- and 62- states were measured using the mirror symmetric centroid difference (MSCD) method with fast-timing LaBr3(Ce) scintillator detectors. The B(M1) values of the 61-→51- and 62-→51- transitions were deduced, and all observed states were interpreted as members of the πd5/2-1νf7/2 and πg7/2-1νf7/2 multiplets. In particular, the 51- level is shown to be dominated by the πd5/2-1νf7/2 configuration, solving the discrepancy in its configuration assignment proposed in previous works. These experimental results were compared with the shell model calculations using several different effective interactions. The systematics of low-lying structure in the N=83 isotones Pr142, Pm144, and Eu146 was established.