Exploring masses at the drip line: New MISTRAL results.

The MISTRAL experiment (Mass measurements at ISOLDE/CERN with a Transmission and Radiofrequency spectrometer on-Line), is well suited for mass determination of very short-lived nuclides. Masses are determined by measuring the cyclotron frequency of an ion in a homogeneous magnetic field. This technique is rapid, and capable of very high resolving power (m/Δm∼10[sup 5]). Results have been obtained in conformity with all aspects of the projected spectrometer performance: masses of nuclides with half-lives as short as 30 ms have been measured and accuracies of ∼5×10[sup -7] have been achieved. Masses of several nuclides have been significantly improved. The [sup 30]Na and [sup 32]Mg results show an overbinding compared to previous measurements, indicating enhanced deformation, where N=20 magicity was expected. Recently the N=Z nuclide [sup 74]Rb has been measured. This mass will allow to study the Wigner energy. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]