Search results for "HYPERFINE"
showing 10 items of 428 documents
On-Line Ion Cooling and Bunching for Collinear Laser Spectroscopy
2002
A new method has been developed for increasing the sensitivity of collinear laser spectroscopy. The method utilizes an ion-trapping technique in which a continuous low-energy ion beam is cooled and accumulated in a linear Paul trap and subsequently released as a short ( $10--20\ensuremath{\mu}\mathrm{s}$) bunch. In collinear laser measurements the signal-to-noise ratio has been improved by a factor of $2\ifmmode\times\else\texttimes\fi{}{10}^{4}$, allowing spectroscopic measurements to be made with ion-beam fluxes of $\ensuremath{\sim}50\mathrm{ions}{\mathrm{s}}^{\ensuremath{-}1}$. The bunching method has been demonstrated in an on-line isotope shift and hyperfine structure measurement on r…
Charge radii and electromagnetic moments of At195–211
2018
Hyperfine-structure parameters and isotope shifts of At195-211 have been measured for the first time at CERN-ISOLDE, using the in-source resonance-ionization spectroscopy method. The hyperfine structures of isotopes were recorded using a triad of experimental techniques for monitoring the photo-ion current. The Multi-Reflection Time-of-Flight Mass Spectrometer, in connection with a high-resolution electron multiplier, was used as an ion-counting setup for isotopes that either were affected by strong isobaric contamination or possessed a long half-life; the ISOLDE Faraday cups were used for cases with high-intensity beams; and the Windmill decay station was used for short-lived, predominantl…
Combined high-resolution laser spectroscopy and nuclear decay spectroscopy for the study of the low-lying states inFr206,At202, andBi198
2016
High-resolution laser spectroscopy was performed on $^{206}\mathrm{Fr}$ with the collinear resonance ionization spectroscopy (CRIS) experiment at CERN-ISOLDE. The hyperfine structure and isotope shift of the ground, first isomeric and second isomeric states were measured. The hyperfine components were unambiguously assigned to each nuclear state by means of laser-assisted nuclear decay spectroscopy. The branching ratios in the $\ensuremath{\alpha}$ decay of $^{206}\mathrm{Fr}$ and $^{202}\mathrm{At}$ were also measured for the first time with isomerically purified beams. The extracted hindrance factors allow determination of the spin of the ground, first isomeric, and second isomeric states…
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.