65 research outputs found
Optical polarization of neutron-rich sodium isotopes and -NMR measurements of quadrupole moments
The nuclear quadrupole moments of neutron-rich sodium isotopes are being investigated with the help of in-beam polarization by optical pumping in combination with -NMR techniques. First measurements have yielded the quadrupole splittings of NMR signals in the lattice of LiNbO for the isotopes Na, Na and Na. Interaction constants and ratios of the electric quadrupole moments are derived. In view of future experiments, -decay asymmetries for the sequence of isotopes up to the =20 neutron shell closure, Na, have been measured
Moments and mean square charge radii of short-lived argon isotopes
We report on the measurement of optical isotope shifts for Ar and for Ar from which the changes in mean square nuclear charge radii across the N = 20 neutron shell closure are deducted. The investigations were carried out by collinear laser spectroscopy in fast beams of neutral argon atoms. The ultra-sensitive detection combines optical pumping, state-selective collisional ionization and counting of -radioactivity. By reaching far into the sd-shell, the results add new information to the systematics of radii in the calcium region (Z 20). Contrary to all major neutron shell closures with N 28, the N = 20 shell closure causes no significant slope change in the development of the radii. Information from the hyperfine structure of the odd-A isotopes includes includes the magnetic moments of Ar (I=1/2) and Ar (I=7/2), and the quadrupole moments of Ar, Ar (I=3/2) and Ar. The electromagnetic moments are compared to shell-model predictions for the sd- and fp-shell. Even far from stability a very good agreement between experiment and theory is found for these quantities. The mean square charge radii are discussed in the framework of spherical SGII Skyrme-type Hartree-Fock calculations
Laser spectroscopy investigation of the nuclear moments and radii of lutetium isotopes
Collinear laser spectroscopy experiments in the LuI transition 5d6s\!^{2} \; ^{2}\!D_{3/2} \rightarrow 5d6s6p \; ^{2}\!D_{3/2} were performed on all lutetium isotopes in the range of Lu. The nuclear spins, magnetic moments and quadrupole moments were determined from the hyperfine structures observed for 19 ground states and 11 isomers. Variations in the mean square charge radii as a function of neutron number were obtained from the isotope shifts. These data considerably extend the systematics of the properties of nuclei in the upper rare-earth region. A particular feature is the appearance of high-spin and low-spin ground states and isomeric states in the vicinity of the stable Lu, partly arising from aligned neutron pairs. The present results clearly show that the deformation properties are nearly independent of the occupancy and the coupling of single-particle states. Theoretical predictions of deformation are confirmed in a consistent description of the measured radii and quadrupole moments. For all observed states, the spins and magnetic moments allow the assignment of rather pure Nilsson configurations
Quadrupole moments and mean-square charge radii in the bismuth isotope chain
Isotope shifts and hyperfine structures of the Bi isotopes have been studied on the 306.7nm line using gas cell laser spectroscopy. The neutron-rich isotopes are the first isotones of Pb to be measured immediately above the N=126 shell closure. The ground state quadrupole moments of the even--N isotopes increase as neutrons are added or removed from the N=126 shell, but no corresponding increase is observed in the charge radii
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