New mass measurements of neutron-rich nuclei near N = 20

International audienceThe masses of 39 neutron-rich nuclei in the mass range 17–37 have been measured using a direct time-of-flight technique following the fragmentation of a 48Ca beam at 55 MeV/nucleon. The masses of 29,30Ne, 34,35Mg and 36,37Al are reported for the first time. The very neutron-rich nuclei, 31–33Na, are found to be 2–4 MeV less bound than previously believed. A comparison is made with recently available large scale shell model calculations encompassing the deformed A∼32 nuclei. Conclusions are drawn regarding the extent of the region of deformation, which is found to include 30Ne