Differences in mean-square nuclear charge radii of ^{100-130}Cd are extracted from high-resolution collinear laser spectroscopy of the 5s ^{2}S_{1/2}→5p ^{2}P_{3/2} transition of the ion and from the 5s5p ^{3}P_{2}→5s6s ^{3}S_{1} transition in atomic Cd. The radii show a smooth parabolic behavior on top of a linear trend and a regular odd-even staggering across the almost complete sdgh shell. They serve as a first test for a recently established new Fayans functional and show a remarkably good agreement in the trend as well as in the total nuclear charge radius.

Transition frequencies of the \(2s\,^2{\text{S}}_{1/2} \rightarrow 2p\,^2 {\text{P}}_{1/2,\,3/2}\) transitions in Be\(^+\) were measured in stable and short-lived isotopes at ISOLDE (CERN) using collinear laser spectroscopy and frequency-comb-referenced dye lasers. Quasi-simultaneous measurements in copropagating and counterpropagating geometry were performed to become independent from acceleration voltage determinations for Doppler-shift corrections of the fast ion beam. Isotope shifts and fine-structure splittings were obtained from the transition frequencies measured with a frequency comb with accuracies better than 1 MHz and led to a precise determination of the nuclear charge radii of \(^{7,10-12}\)Be relative to the stable isotope 9Be. Moreover, an accurate determination of the 2p fine-structure splitting allowed a test of high-precision bound-state QED calculations in the three-electron system. Here, we describe the laser spectroscopic method in detail, including several tests that were carried out to determine or estimate systematic uncertainties. Final values from two experimental runs at ISOLDE are presented, and the results are discussed.

A negative magnetic moment of 23Mg has been determined by collinear laser spectroscopy at CERN-ISOLDE. The absolute value is in agreement with previous measurements by nuclear magnetic resonance while the sign points at high-seniority configurations. The result is consistent with shell-model predictions for nuclei with valence nucleons in the sd shell.

Isomer shifts have been determined in ^{111-129}Cd by high-resolution laser spectroscopy at CERN-ISOLDE. The corresponding mean square charge-radii changes, from the 1/2^{+} and the 3/2^{+} ground states to the 11/2^{-} isomers, have been found to follow a distinct parabolic dependence as a function of the atomic mass number. Since the isomers have been previously associated with simplicity due to the linear mass dependence of their quadrupole moments, the regularity of the isomer shifts suggests a higher order of symmetry affecting the ground states in addition. A comprehensive description assuming nuclear deformation is found to accurately reproduce the radii differences in conjunction with the known quadrupole moments. This intuitive interpretation is supported by covariant density functional theory.

We report on improved isotope shift measurements of the isotopes Ca-40,Ca-42,Ca-44,Ca-48 in the 4s S-2(1/2) -> 4p P-2(3/2) (D2) transition using collinear laser spectroscopy. Accurately known isotope shifts in the 4s S-2(1/2) -> 4p P-2(1/2)(D1) transition were used to calibrate the ion beam energy with an uncertainty of Delta U approximate to +/- 0.25 V. The accuracy in the D2 transition was improved by a factor of 5-10. A King-plot analysis of the two transitions revealed that the field shift factor in the D2 line is about 1.8(13)% larger than in the D1 transition which is ascribed to relativistic contributions of the (4)p(1/2) wave function.

We report on improved isotope shift measurements of the isotopes 40,42 , 44,48 ?> Ca in the 4 s 2 S 1 / 2 → 4 p 2 P 3 / 2 ?> (D2) transition using collinear laser spectroscopy. Accurately known isotope shifts in the 4 s 2 S 1 / 2 → 4 p 2 P 1 / 2 ?> (D1) transition were used to calibrate the ion beam energy with an uncertainty of Δ U ≈ ± 0.25 V . ?> The accuracy in the D2 transition was improved by a factor of 5–10. A King-plot analysis of the two transitions revealed that the field shift factor in the D2 line is about 1.8(13)% larger than in the D1 transition which is ascribed to relativistic contributions of the 4 p 1 / 2 ?> wave function.

We give a brief overview of time dilation tests using high-resolution laser spectroscopy at heavy-ion storage rings. We reflect on the various methods used to eliminate the first-order Doppler effect and on the pitfalls encountered, and comment on possible extensions at future facilities providing relativistic heavy ion beams at γ≫ 1.

A linear Paul trap for cooling of ion beams, the former cooler for emittance elimination radiofrequency quadrupole (RFQ) at MISTRAL/ISOLDE, has been installed and commissioned at the TRIGA-SPEC experiment located at the research reactor TRIGA Mainz. It is connected to a hot-surface-ionization ion source and a subsequent mass separator for ionization and pre-separation of neutron-rich fission products as delivered from the reactor. The capability of accumulating and bunching ion beams has been implemented to provide low-emittance ion pulses of 250 ns width containing up to 10(6) ions. A technical description of the upgraded RFQ as well as its characterization with stable ions is presented. Its installation allows delivery of low-emittance ion bunches to the two branches of the TRIGA-SPEC experiment, namely TRIGA-TRAP and TRIGA-LASER.

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.

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.

We propose to study the neutron-deficient cadmium isotopes with high-resolution laser spectroscopy for the first time. Our goal is to determine nuclear spins, electromagnetic moments and rms charge radii towards N = 50, contributing decisively to a better understanding of the nuclear structure in the vicinity of the doubly-magic Sn. keywords: cadmium, spins, electromagnetic moments, radii, COLLAPS Requested shifts: 9 shifts of radioactive beam and 2 shifts of stable beam

Charge radii of all magnesium isotopes in the sd shell have been measured, revealing evolution of the nuclear shape throughout two prominent regions of assumed deformation centered on (24)Mg and (32)Mg. A striking correspondence is found between the nuclear charge radius and the neutron shell structure. The importance of cluster configurations towards N=8 and collectivity near N=20 is discussed in the framework of the fermionic molecular dynamics model. These essential results have been made possible by the first application of laser-induced nuclear orientation for isotope shift measurements.

The installation of an ion–beam cooler–buncher at the ISOLDE, CERN facility has provided increased sensitivity for collinear laser spectroscopy experiments. A migration of single-particle states in gallium and in copper isotopes has been investigated through extensive measurements of ground state and isomeric state hyperfine structures. Lying beyond the N = 50 shell closure, 82Ga is the most exotic nucleus in the region to have been studied by optical methods, and is reported here for the first time.

The performance characteristics of two charge-exchange cells (CECs) with horizontal and vertical cell configurations were determined by neutralizing a 10-keV rubidium ion beam in a potassium vapor. The neutralization efficiency and the fluorescence line shape of the 5s 2S1/2↔5p 2P3/2 (D2) transition in neutral 85Rb were investigated as a function of the reservoir temperature used to control the potassium vapor density. The CECs exhibited similar neutralization performance and at neutralization efficiencies greater than 25–50% an asymmetric line shape of the rubidium D2 fluorescent signal was observed. The asymmetry was attributed to inelastic channels in the charge-exchange process. The rubidium D2 fluorescence line shape was fitted with a multiple Voigt function, which quantitatively models the inelastic channels. In the present Rb+ + K charge-exchange process, the optimum neutralization efficiency to accurately determine the centroid of the Rb D2 resonance line shape was obtained by fitting single Voigt functions to the resonance spectra obtained at neutralization efficiencies where inelastic processes were negligible.

Collinear laser spectroscopy was performed on the Ga-63,Ga-64,Ga-66,Ga-68-82 isotopes with neutron numbers from N = 32 to N = 51. These measurements were carried out at the ISOLDE radioactive ion beam facility at CERN. Here we present the nuclear mean-square charge radii extracted from the isotope shifts and, for the lighter isotopes, new spin and moment values. New ground-state nuclear spin and moments were extracted from the hyperfine spectra of Ga-63,Ga-70, measured on an atomic transition in the neutral atom. The ground-state spin of Ga-63 is determined to be I = 3/2. Analysis of the trend in the change in mean-square charge radii of the gallium isotopes demonstrates that there is no evidence of anomalous charge radii behavior in gallium in the region of N = 32.

This paper reports on the ground state nuclear moments measured in 58–62Cu using collinear laser spectroscopy at the ISOLDE facility. The quadrupole moments for 58–60Cu have been measured for the first time as Q(Cu58)=−15(3) efm2, Q(Cu59)=−19.3(19) efm2, Q(Cu60)=+11.6(12) efm2 and with higher precision for 61,62Cu as Q(Cu61)=−21.1(10) efm2, Q(Cu62)=−2.2(4) efm2. The magnetic moments of 58,59Cu are measured with a higher precision as μ(Cu58)=+0.570(2)μN and μ(Cu59)=+1.8910(9)μN. The experimental nuclear moments are compared to large-scale shell-model calculations with the GXPF1 and GXPF1A effective interactions, allowing the softness of the 56Ni core to be studied.

Laser spectroscopy was performed on the Ga-72,Ga-74,Ga-76,Ga-78 isotopes at On-Line Isotope Mass Separator (ISOLDE) facility, CERN. Ground-state nuclear spins and moments were extracted from the measured hyperfine spectra. The results are compared to shell-model calculations, which provide a detailed probe of the nuclear wave function. The spin is established from the shape of the hyperfine structure and the parity inferred from a comparison of shell-model calculations with the measured nuclear moments. The ground states of Ga-76,Ga-78 are both assigned a spin and parity of I-pi = 2(-), while Ga-74 is tentatively assigned as I-pi = 3(-). For Ga-72, the results are consistent with the previous I = 3 assignment.