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The nuclear charge radii of $^{7,9,10,11}$Be have been determined by high-precision laser spectroscopy. On-line measurements were performed at ISOLDE with collinear laser spectroscopy in the $2s_{1/2} \to 2p_{1/2}$ transition of Be$^{+}$. Simultaneous measurements in collinear and anti-collinear direction combined with absolute frequency determination using a frequency comb yielded accuracy in the isotope shift measurements of better than 1 MHz. Combined with accurate calculations of the mass-dependent isotope shifts the nuclear charge radii along the isotopic chain were extracted. The charge radius decreases from $^7$Be to $^{10}$Be and then increases for the halo nucleus $^{11}$Be. When comparing our results with predictions of {\it ab-initio} nuclear structure calculations we find good agreement. Additionally, the nuclear magnetic moment of $^7$Be was determined to be 1.3998(15) $\mu_{\rm N}$ and that of $^{11}$Be was confirmed with an accuracy similar to previous $\beta$-NMR measurements. The nuclear charge radii of $^{7,9,10,11}$Be have been determined by high-precision laser spectroscopy. On-line measurements were performed at ISOLDE with collinear laser spectroscopy in the $2s_{1/2} \to 2p_{1/2}$ transition of Be$^{+}$. Simultaneous measurements in collinear and anti-collinear direction combined with absolute frequency determination using a frequency comb yielded accuracy in the isotope shift measurements of better than 1 MHz. Combined with accurate calculations of the mass-dependent isotope shifts the nuclear charge radii along the isotopic chain were extracted. The charge radius decreases from $^7$Be to $^{10}$Be and then increases for the halo nucleus $^{11}$Be. When comparing our results with predictions of {\it ab-initio} nuclear structure calculations we find good agreement. Additionally, the nuclear magnetic moment of $^7$Be was determined to be -1.3995(5) $\mu_{\rm N}$ and that of $^{11}$Be was confirmed with an accuracy similar to previous $\beta$-NMR measurements.

Perched precariously on the brink of nuclear stability, 11Li has the lowest two-neutron binding energy of all nuclei. This gives rise to the exotic phenomena of a nuclear halo that has a wavefunction extending beyond the range normally allowed for by the strong interaction. The most accurate mass measurements are achieved using Penning traps. In this letter, we report a new mass for 11Li using the TITAN trapping experiment at TRIUMF's ISAC facility where 'designer atomic nuclei' can be produced and studied in detail. This is by far the shortest-lived nuclide, t1/2 = 8.8 ms, for which a mass measurement has ever been performed with a Penning trap. We derive a new two-neutron separation energy of 369.15(65) keV: seven times more precise than the best previous value. We also report results from state-of-the-art atomic-physics calculations using the new mass and extract a new charge radius for 11Li from recent isotope shift measurements

Expérience GANIL; International audience; The root-mean-square (rms) nuclear charge radius of ^8He, the most neutron-rich of all particle-stable nuclei, has been determined for the first time to be 1.93(3) fm. In addition, the rms charge radius of ^6He was measured to be 2.068(11) fm, in excellent agreement with a previous result. The significant reduction in charge radius from ^6He to ^8He is an indication of the change in the correlations of the excess neutrons and is consistent with the ^8He neutron halo structure. The experiment was based on laser spectroscopy of individual helium atoms cooled and confined in a magneto-optical trap. Charge radii were extracted from the measured isotope shifts with the help of precision atomic theory calculations.