Study of the nuclear structure of 155Eu

The 155Eu nuclide was investigated by the directional angular correlation technique following the β decay of 155Sm. The angular correlation measurements were carried out using a setup with 4 Ge detectors and a multi parametric data acquisition system. To perform the data analysis a new methodology was developed . The multipole mixing ratios of twenty sixty γ- transitions were determined. Seven of them agreed with the results of earlier angular correlation studies and nineteen obtained for the first time confirmed the multipolarity suggested in earlier electron capture studies. Besides, the spin of the level at 1106.83 keV as well as the parity of the level at 1301.41 keV have also been suggested. The nuclear structure of 155Eu was discussed successfully in terms of the single particle model using a deformed Woods-Saxon potential plus residual pairing interaction permitting the description of the rotational quasi-proton band heads. (author)