Search results for "Hyperfine"
showing 10 items of 428 documents
Hyperfine structure and isotope shift investigations in $^{202-222}$Rn for the study of nuclear structure beyond Z = 82
1986
The hyperfine structure (hfs) and isotope shift (IS) in the isotopic chain of the radioactive element radon have been studied for the first time. The measurements were carried out by collinear fast-beam laser spectroscopy at the mass separator facility ISOLDE at CERN. The IS between 16 isotopes in the mass range 202≦A≦222 and the hfs of 7 odd-A isotopes were determined in the transitions 7s [3/2]2-7p [5/2]3 (745 nm) of Rn I. The nuclear spins and moments, as well as the observed inversion of the odd-even staggering for218–222Rn, can be associated with the effects of octupole instability around N=134.
A gas-jet apparatus for high-resolution laser spectroscopy on the heaviest elements at SHIP
2020
© 2019 Elsevier B.V. Laser spectroscopy enables the determination of fundamental atomic and nuclear properties with high precision. In view of the low production rates of the heaviest elements, a high total efficiency is a crucial requirement for any experimental setup to be used in on-line experiments. The setup requires the use of gas stopping techniques to slow down the radionuclides of interest. In previous studies laser spectroscopy was performed inside a gas-filled stopping cell with a limited spectral resolution of a few GHz. Collisional broadening inside stopping cells ultimately limits the precision of laser spectroscopic studies and hampers in particular hyperfine spectroscopy. Th…
Nuclear ground state properties from optical investigations
1986
Recent progress in on-line techniques of laser spectroscopy applied to nuclei far off stability is reviewed. The results concern nuclear spins, moments and charge radii, determined from hyperfine structure and isotope shift of atomic transitions. Examples of large core polarizations in the Cd-In-Sn region, derived from isotope shifts, and the octupole deformation in the Ra region, derived from ground state spins and magnetic moments, are discussed.
Collinear laser spectroscopy of stable palladium isotopes at the IGISOL facility
2020
AbstractCollinear laser spectroscopy on stable palladium isotopes was performed at the IGISOL facility in Jyväskylä in preparation for an experiment on its neutron-rich isotopes. Five transitions from different initial atomic states were tested, with the goal of finding the most spectroscopically efficient. The observed intensities afforded a comparison with atomic-level population predictions based on charge-exchange calculations. For some transitions hyperfine parameters of 105Pd were measured, which were found to be in good agreement with literature values. A King plot analysis was performed using the measured isotope shifts and known charge radii from literature to determine the atomic …
Laser spectroscopy and β-decay asymmetry from on-line implanted nuclei
1985
The method of collinear laser spectroscopy is combined with s-radiation detected optical pumping by implanting the optically oriented atoms into a cubic crystal.
Electric hyperfine interaction in199Hg fluorides
1985
With the current integration technique, the Mossbauer effect on the 158 keV, 5/2−→1/2− transition in199Hg was studied using the cubic HgF2 and the tetragonal Hg2F2 as absorbers; in the latter, a quadrupole splittingeQVzz=}- 9.0(2) mm/s was observed. Electron densities were calculated with the self-consistent-charge-extended-Hueckel-molecular-orbital method and δ〈r2〉=(3.26±0.11) fm2 derived. From the quadrupole splitting and the calculation, an effective antishielding factor almost twice that of the neutral Hg atom is derived.
Generation of a 7.4 mT ESR doublet induced by γ rays in amorphous-SiO2
2000
Abstract Paramagnetic defects induced by γ rays, in a dose range from 1 to 1000 Mrad, have been investigated by electron spin resonance (ESR) spectroscopy in various types of natural and synthetic silica, having different OH content. A doublet with a field splitting of 7.4 mT, arising from the hyperfine interaction of an unpaired electron with a H nucleus associated with the H(I) center, was detected in all the investigated samples. This ESR structure exhibits a sublinear growth with the γ dose linearly correlated with the γ-induced photoluminescence band at 4.4 eV. The intensity ratio of these two signals depends on the OH content of the sample. Our results agree with a model in which the …
Bleaching and thermal recovery of PL emissions in natural silica
2000
Abstract We have investigated the bleaching of two photoluminescence (PL) emissions at 3.1 and 4.2 eV and the related growth of an electron spin resonance (ESR) signal, consisting in a hyperfine doublet split by 11.8 mT, in natural silica γ-irradiated by low doses, up to 1 Mrad. These observations definitely support the existence of a conversion mechanism, from optically active defects to paramagnetic ones. To further investigate this conversion process and the stability of the γ-induced paramagnetic centers, we performed PL and ESR measurements in samples that, after a γ exposure at 1 Mrad dose, were thermally treated at various temperatures ranging from 330 to 430 K. We found that the int…
Precision spectroscopy on trapped atomic ions
1987
Recent examples of lifetime measurements, ground state hyperfine splittings and spectroscopy on minute samples of radioactive ions illustrate the extension of classical methods of spectroscopy to new regions of interest by the use of ion storage techniques. Estimates are given on the sensitivity of the method with respect to be possible investigation of the Bohr-Weisskopf effect in isotopic chains of elements.
Evidence for Increased neutron and proton excitations between 51−63 Mn
2015
The hyperfine structures of the odd-even 51−63Mnatoms (N=26 −38) were measured using bunched beam collinear laser spectroscopy at ISOLDE, CERN. The extracted spins and magnetic dipole moments have been compared to large-scale shell-model calculations using different model spaces and effective interactions. In the case of 61,63Mn, the results show the increasing importance of neutron excitations across the N=40subshell closure, and of proton excitations across the Z=28shell gap. These measurements provide the first direct proof that proton and neutron excitations across shell gaps are playing an important role in the ground state wave functions of the neutron-rich Mn isotopes. publisher: Els…