β-Decay schemes of very neutron-rich sodium isotopes and their descendants

The γ-activities from the β-decay of Na isotopes up to 34Na, formed in high-energy fragmentation and analysed through mass-spectrometry techniques, are observed as well as those from their Mg descendants. The Iγ, intensities, the β-delayed one- and two-neutron probabilities and the Iβ intensities are measured. Decay schemes are proposed. We confirm, from the low location of the first 2+ level of 32Mg, the occurrence of a nuclear deformation at Z ⋍ 11, N ⋍ 20.