Collective excitations in the transitional nuclei 224, 226Ra

The γ-rays following the β − decay of 224,226 Fr have been investigated by means of γ-ray singles including multispectrum analysis and γ-γ coincidence measurements using Ge(Li) spectrometers. Most of the observed transitions could be placed in level schemes comprising 40 excited states of 224 Ra and 40 excited states of 226 Ra. The properties of the collective states of 224,226 Ra are discussed. It is concluded that the ground states of these nuclei possess a non-zero octupole deformation.