Octupole deformation in the odd-odd nucleus 154Eu

Octupole deformation has been observed for the first time in the detailed spectroscopy of an odd-odd nucleus in 154Eu. 15 parity doublet bands or band heads are observed including most of the known levels below 600 keV. El transition probabilities are enhanced by ≈ 102 compared to the normal transitions in 154Eu.