Search results for "hyperfine structure"
showing 10 items of 423 documents
Precision measurements of the charge radii of potassium isotopes
2019
International audience; Precision nuclear charge radii measurements in the light-mass region are essential for understanding the evolution of nuclear structure, but their measurement represents a great challenge for experimental techniques. At the Collinear Resonance Ionization Spectroscopy (CRIS) setup at ISOLDE-CERN, a laser frequency calibration and monitoring system was installed and commissioned through the hyperfine spectra measurement of $^{38–47}$K. It allowed for the extraction of the hyperfine parameters and isotope shifts with better than 1 MHz precision. These results are in excellent agreement with available literature values and they demonstrate the suitability of the CRIS tec…
Laser Spectroscopy of Short-Lived Isotopes in Fast Atomic Beams and Resonance Cells
1979
The introduction of laser techniques to optical spectroscopy of hyperfine structure (HFS) and isotope shift (IS) has put new life into this field at the intersection between atomic and nuclear physics which is now about fifty years old. Two severe limitations of classical spectroscopy could be reduced drastically, i.e., (i) the amount of atoms needed for optical spectroscopy and (ii) the Doppler width of optical lines. The increase in sensitivity went together with the development of powerful accelerators or reactors so that exotic nuclei with half lives down to 10 msec can now be produced and optically analysed. The increase in resolution allows the determination of nuclear spins, nuclear …
First observation of the blue optical lines of francium
1987
We report here the first wave-length measurements in the second resonance doublet of francium, D1'(7s2S1/2-8p2P 1/2) and D2'(7s2S1/2-8p2P 3/2), carried out by collinear fast-beam laser spectroscopy. The transition wave numbers are D1' = 23112.9603(50) cm-1 and D2' = 23658.3058(40) cm-1, corresponding to a 8p fine-structure splitting of δW8p = 545.3454(70) cm-1. In addition the hyperfine structure in both lines and the isotope shift in the D2' line for the isotopes 212,213,220,221Fr have been measured. The results are discussed with special emphasis on the analysis of the atomic structure in the heaviest alkali element and compared with theoretical predictions, as well as the only earlier sp…
Nuclear spin and moments of 73Kr and odd—even staggering in the radii of light krypton isotopes
2003
Nuclear spectroscopy measurements in the region of neutron-deficient krypton isotopes have indicated that pronounced shape changes and instabilities occur when the nuclei approach the N = Z line. This is confirmed by isotope shift measurements on krypton [1] yielding an increasing inverted odd—even staggering of the radii [2] from 82Kr (N = 46) to 74Kr (N = 38). We have now completed the published data by measuring the hyperfine structure and isotope shift of 73Kr. This is also interesting in context with a recent β-decay study [3]. The feeding of excited states in 73Br gave strong arguments for the ground-state spin and parity of 73Kr to be 3/2−, in contrast to the adopted assignment of 5/…
Isotope shifts and hyperfine structure in the $\mathsf{ 3d ^2D_J \rightarrow 4p ^2P_J}$ transitions in calcium II
1998
The isotope shift and hyperfine structure in the three \(\) - transitions in Ca II have been studied by fast ion beam collinear laser spectroscopy for all stable Ca isotopes. The metastable 3d states were populated within the surface ionization source of a mass separator with a probability of about 0.1%. After resonant excitation to the 4p levels with diode laser light around 850 nm the uv photons from the \(\) transitions to the ground state were used for detection. Hyperfine structure parameters A and B for the odd isotope 43Ca, as evaluated from the splittings observed, agree well with theoretical predictions from relativistic many-body perturbation theory. Field shift constants \(\) and…
Isotope shifts and hyperfine structure in calcium 4snp and 4snf F Rydberg states
2000
Isotope shifts and hyperfine structure have been measured in 4snp 1 P1 and Rydberg states for all stable calcium isotopes and the radioisotope 41Ca using high-resolution laser spectroscopy. Triple-resonance excitation via Rydberg state was followed by photoionization with a CO2 laser and mass selective ion detection. Isotope shifts for the even-mass isotopes have been analyzed to derive specific mass shift and field shift factors. The apparent isotope shifts for 41Ca and 43Ca exhibit anomalous values that are n-dependent. This is interpreted in terms of hyperfine-induced fine-structure mixing, which becomes very pronounced when singlet-triplet fine-structure splitting is comparable to the h…
Hyperfine structure andg-factor measurements in ion traps
1995
We report about measurements on ground-state hyperfine splitting constants of stable Eu+ isotopes in radio frequency ion traps and experiments on the electronicg-factor of Ba+ in a Penning trap. From the precision of both measurements, which ranges between 3·10−6 and 5·10−7, we conclude that precise determination of the differential Bohr-Weisskopf effect in chains of isotopes will be possible in the near future.
Isotope shifts from collinear laser spectroscopy of doubly charged yttrium isotopes
2018
Collinear laser spectroscopy has been performed on doubly charged ions of radioactive yttrium in order to study the isotope shifts of the 294.6-nm $5s\phantom{\rule{0.16em}{0ex}}^{2}S_{1/2}\ensuremath{\rightarrow}5p\phantom{\rule{0.16em}{0ex}}^{2}P_{1/2}$ line. The potential of such an alkali-metal-like transition to improve the reliability of atomic-field-shift and mass-shift factor calculations, and hence the extraction of nuclear mean-square radii, is discussed. Production of yttrium ion beams for such studies is available at the IGISOL IV Accelerator Laboratory, Jyv\"askyl\"a, Finland. This newly recommissioned facility is described here in relation to the on-line study of accelerator-p…
Isotope shifts and nuclear-charge radii in singly ionizedCa40–48
1992
The isotope shifts in the resonance lines 4${\mathit{s}}_{1/2}$\ensuremath{\rightarrow}4${\mathit{p}}_{1/2,3/2}$ in Ca ii have been measured for the isotopes $^{40\mathrm{\ensuremath{-}}48}\mathrm{Ca}$ by fast-ion-beam collinear laser spectroscopy. Atomic many-body perturbation theory was then used to calculate the electronic factor for the field shift, giving F=-285(3) MHz/${\mathrm{fm}}^{2}$. The estimate of the uncertainty in F is based on the agreement at the level of 1% for the 4s and 4p hyperfine structures obtained using the same wave functions which include core polarization and pair correlation to all orders. The theoretical value is in excellent agreement with the result F=-283(6)…
Hyperfine structure study of Tc97,98,99 in a new laser ion source for high-resolution laser spectroscopy
2020
Using a novel concept for efficient laser spectroscopy, we investigated the hyperfine splittings of three different atomic transitions in the long-lived isotopes $^{97\ensuremath{-}99}\mathrm{Tc}$. Despite the refractory character of the element technetium, sample sizes as low as ${10}^{11}$ atoms were sufficient to achieve excellent signal-to-noise ratios at a spectroscopic linewidth of less than 100 MHz. The obtained spectra were analyzed in detail, which results in a very good consistency for the extracted hyperfine parameters from the different transitions. The presented measurements provide the first hyperfine structure data for the isotopes $^{97,98}\mathrm{Tc}$ from which, in combina…