D. T. Yordanov

Nuclear Charge Radii of Be-7, Be-9, Be-10 and the one-neutron halo nucleus Be-11

Nuclear charge radii of ;{7,9,10,11}Be have been determined by high-precision laser spectroscopy. On-line measurements were performed with collinear laser spectroscopy in the 2s_{1/2}-->2p_{1/2} transition on a beam of Be+ ions. Collinear and anticollinear laser beams were used simultaneously, and the absolute frequency determination using a frequency comb yielded an accuracy in the isotope-shift measurements of about 1 MHz. Combining this with accurate calculations of the mass-dependent isotope shifts yields nuclear charge radii. The charge radius decreases from 7Be to 10Be and then increases for the halo nucleus 11Be. When comparing our results with predictions of ab initio nuclear-structure calculations we find good agreement. Additionally, the nuclear magnetic moment of 7Be was determined to be -1.3995(5)micro_{N} and that of 11Be was confirmed with an accuracy similar to previous beta-NMR measurements.

Nuclear charge radii of 7,9,10Be and the one-neutron halo nucleus 11Be.

Nuclear charge radii of ;{7,9,10,11}Be have been determined by high-precision laser spectroscopy. On-line measurements were performed with collinear laser spectroscopy in the 2s_{1/2}-->2p_{1/2} transition on a beam of Be+ ions. Collinear and anticollinear laser beams were used simultaneously, and the absolute frequency determination using a frequency comb yielded an accuracy in the isotope-shift measurements of about 1 MHz. Combining this with accurate calculations of the mass-dependent isotope shifts yields nuclear charge radii. The charge radius decreases from 7Be to 10Be and then increases for the halo nucleus 11Be. When comparing our results with predictions of ab initio nuclear-structure calculations we find good agreement. Additionally, the nuclear magnetic moment of 7Be was determined to be -1.3995(5)micro_{N} and that of 11Be was confirmed with an accuracy similar to previous beta-NMR measurements.

Nuclear Charge Radius of 12 Be

The nuclear charge radius of (12)Be was precisely determined using the technique of collinear laser spectroscopy on the 2s(1/2)→2p(1/2,3/2) transition in the Be(+) ion. The mean square charge radius increases from (10)Be to (12)Be by δ(10,12)=0.69(5) fm(2) compared to δ(10,11)=0.49(5) fm(2) for the one-neutron halo isotope ^{11}Be. Calculations in the fermionic molecular dynamics approach show a strong sensitivity of the charge radius to the structure of ^{12}Be. The experimental charge radius is consistent with a breakdown of the N=8 shell closure.

Spins, Electromagnetic Moments, and Isomers of 107-129Cd

The neutron-rich isotopes of cadmium up to the N=82 shell closure have been investigated by high-resolution laser spectroscopy. Deep-uv excitation at 214.5 nm and radioactive-beam bunching provided the required experimental sensitivity. Long-lived isomers are observed in (127)Cd and (129)Cd for the first time. One essential feature of the spherical shell model is unambiguously confirmed by a linear increase of the 11/2(-) quadrupole moments. Remarkably, this mechanism is found to act well beyond the h(11/2) shell.

Isotope shift measurements in the 2s1/2 → 2p3/2 transition of Be+ and extraction of the nuclear charge radii for 7, 10, 11Be

We have performed isotope shift measurements in the 2s1/2 → 2p3/2 transition of Be + ions using advanced collinear laser spectroscopy with two counterpropagating laser beams. Measurements involving a frequency comb for laser stabilization and absolute frequency determination allowed us to determine the isotope shifts with an accuracy of 2 MHz. From the isotope shifts between 9 Be and 7,10,11 Be, high-accuracy mass shift calculations and the charge radius of the reference isotope 9 Be we determined nuclear charge radii for the isotopes 7,10 Be and the one-neutron halo nucleus 11 Be. The results are compared to nuclear-structure calculations using the fermionic molecular dynamics model which reproduce well the general trend of the radii. Decreasing charge radii from 7 Be to 10 Be are explained by the cluster structure of the nuclei. The increase from 10 Be to 11 Be is mainly caused by the halo neutron by which the 10 Be core moves relative to the center of mass. Polarization of the 10 Be core

Precision measurement of 11Li moments: influence of halo neutrons on the 9Li core.

The electric quadrupole moment and the magnetic moment of the 11Li halo nucleus have been measured with more than an order of magnitude higher precision than before, |Q| = 33.3(5) mb and mu = +3.6712(3)muN, revealing a 8.8(1.5)% increase of the quadrupole moment relative to that of 9Li. This result is compared to various models that aim at describing the halo properties. In the shell model an increased quadrupole moment points to a significant occupation of the 1d orbits, whereas in a simple halo picture this can be explained by relating the quadrupole moments of the proton distribution to the charge radii. Advanced models so far fail to reproduce simultaneously the trends observed in the radii and quadrupole moments of the lithium isotopes.

Nuclear spins, magnetic moments, and quadrupole moments of Cu isotopes from N = 28 to N = 46: Probes for core polarization effects

Measurements of the ground-state nuclear spins and magnetic and quadrupole moments of the copper isotopes from

Nuclear Charge Radius of 12Be

^{61}\mathrm{Cu}

Calibration of the ISOLDE acceleration voltage using a high-precision voltage divider and applying collinear fast beam laser spectroscopy

up to

Spins and Magnetic Moments of 49K and 51K: Establishing the 1/2+ and 3/2+ Level Ordering Beyond N=28

^{75}\mathrm{Cu}