Search results for "Francium"
showing 7 items of 17 documents
Beta-decay measurements of neutron-rich thallium, lead, and bismuth by means of resonant laser ionisation
2004
Abstract Neutron-rich thallium, lead, and bismuth isotopes were investigated at the ISOLDE facility. After mass separation and resonant laser ionisation of the produced activity, new spectroscopic data were obtained for 215,218 Bi and 215 Pb. An attempt to reach heavy thallium had to be abandoned because of a strong francium component in the beam that gave rise to a neutron background through (α,n) reactions on the aluminium walls of the experimental chamber.
Laser spectroscopy of francium isotopes at the borders of the region of reflection asymmetry
2014
The magnetic dipole moments and changes in mean-square charge radii of the neutron-rich $^{218m,219,229,231}\text{Fr}$ isotopes were measured with the newly-installed Collinear Resonance Ionization Spectroscopy (CRIS) beam line at ISOLDE, CERN, probing the $7s~^{2}S_{1/2}$ to $8p~^{2}P_{3/2}$ atomic transition. The $\delta\langle r^{2}\rangle^{A,221}$ values for $^{218m,219}\text{Fr}$ and $^{229,231}\text{Fr}$ follow the observed increasing slope of the charge radii beyond $N~=~126$. The charge radii odd-even staggering in this neutron-rich region is discussed, showing that $^{220}\text{Fr}$ has a weakly inverted odd-even staggering while $^{228}\text{Fr}$ has normal staggering. This sugges…
Nuclear moments and charge radii of neutron-deficient francium isotopes and isomers
2015
Collinear laser fluorescence spectroscopy has been performed on the ground and isomeric states of $^{204,206}\mathrm{Fr}$ in order to determine their spins, nuclear moments, and changes in mean-squared charge radii. A new experimental technique has been developed as part of this work which much enhances the data collection rate while maintaining the high resolution. This has permitted the extension of this study to the two isomeric states in each nucleus. The investigation of nuclear $g$ factors and mean-squared charge radii indicates that the neutron-deficient Fr isotopes lie in a transitional region from spherical towards more collective structures.
α-decay studies of the francium isotopes198Fr and199Fr
2013
Very neutron deficient francium isotopes have been produced in fusion evaporation reactions using ${}^{60}$Ni ions on ${}^{141}$Pr targets. The gas-filled recoil separator RITU was employed to collect the fusion products and to separate them from the scattered beam. The activities were implanted into a position sensitive silicon detector after passing through a gas-counter system. The isotopes were identified using spatial and time correlations between the implants and the decays. Two $\ensuremath{\alpha}$-particle activities, with ${E}_{\ensuremath{\alpha}}=7613(15)$ keV and ${T}_{1/2}$ $=$ (${15}_{\ensuremath{-}5}^{+12}$) ms and ${E}_{\ensuremath{\alpha}}=7684(15)$ keV and ${T}_{1/2}$ $=$…
Evaluation of the magnetic moment ofRa213
1991
The hyperfine field at the nucleus of singly ionized radium has been investigated using the relativistic linked-cluster many-body-perturbation-theory procedure, including the effects of distributed charge and magnetization over the nucleus. The total hyperfine field of 1239 T, when combined with the experimentally observed hyperfine constant for $^{213}\mathrm{Ra}^{+}$, yields a nuclear moment of 0.607(12)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$, in excellent agreement with the experimentally observed moment of 0.6133(18)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$ from Zeeman measurements. Our investigation leads to exchange core-polarization and correlation contributions of 14% and 13%, r…
Nuclear moments and charge radii of neutron-deficient francium isotopes and isomers
2015
Collinear laser fluorescence spectroscopy has been performed on the ground and isomeric states of 204,206Fr in order to determine their spins, nuclear moments, and changes in mean-squared charge radii. A new experimental technique has been developed as part of this work which much enhances the data collection rate while maintaining the high resolution. This has permitted the extension of this study to the two isomeric states in each nucleus. The investigation of nuclear g factors and mean-squared charge radii indicates that the neutron-deficient Fr isotopes lie in a transitional region from spherical towards more collective structures. peerReviewed
Delayed and In-beam Spectroscopy on Francium and Astatine Nuclei at the Proton Drip Line
2011
Delayed and in‐beam spectroscopy on francium and astatine nuclei at and beyond the proton drip line has been performed. In neutron deficient astatine nuclei a shift to deformed shapes as a function of decreasing neutron has been obtained. In neutron deficient francium isotope the same shift is evident.