Mass measurement of short-lived halo nuclides

A direct mass measurement of the very-short-lived halo nuclide $^{11}$Li (T$_{1/2}$ = 8.7 ms) has been performed with the transmission mass spectrometer MISTRAL. The preliminary result for the two-neutron separation energy is S$_{2n}$ = 376$\pm$ 5 keV, improving the precision seven times with an increase of 20\% compared to the previous value [1]. In order to confirm this value, the mass excess of $^{11}$Be has also been measured, ME = 20171 $\pm$ 4 keV, in good agreement with the previous value [2, 3]