Production of heavy atomic clusters upon interaction of laser radiation with matter

The results of an investigation of the formation of Pb, Th, and U clusters over a broad range of numbers of atoms (from a few atoms to macroparticles) upon interaction of high-power pulsed laser radiation with matter are presented. Clusters of fissionable elements are studied for the first time. A setup for determining the yield of clusters and the number of atoms in them, which is based on the use of several different methods (laser resonance fluorescence, time-of-flight measurements, and counting the number of tracks of fission fragments from the cluster nuclei), is described. The dependence of the yield of clusters with various numbers of atoms on the conditions for their formation is discussed. Zh. éksp. Teor. Fiz. 112, 78–88 (July 1997)     

First results from laser spectroscopy on bunched radioactive beams from the JYFL ion-beam cooler

A new RFQ ion-beam cooler and buncher, installed after the mass-separating magnet of the ion guide isotope separator, IGISOL, JYFL, has dramatically increased the scope of on-line laser spectroscopy at this facility. The device, operated in a bunching mode, has permitted new measurements on short-lived radionuclei in the Ti, Zr and Hf chains at a sensitivity two orders of magnitude greater than that previously achieved. The device has also opened new prospects for laser-based nuclear spectroscopy at the facility, particularly collinear resonance ionisation spectroscopy. Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002 RID="a" ID="a"e-mail: pc@mags.ph.man.ac.uk     

Optical polarization of 24Na nuclei in a trap based on photoinduced drift

The results of experiments on the polarization of nuclei of the 24 Na radioactive isotope in a gas trap are presented. The action of the trap is based on the effect of the photoinduced drift of atoms caused by laser radiation. The anisotropy of γ-radiation emitted by ²⁴Na during the illumination of sodium vapor in the trap by circularly polarized laser radiation is measured and its dependence on the temperature of the trap walls is analyzed. A degree of polarization of ²⁴Na nuclei of 62 ± 2% is attained at temperatures above 1300 K, for which a rapid desorption of Na atoms from the walls and the decomposition of Na-based compounds take place.     

Hyperfine splitting and isotope shift in the optical transition of Eu isotopes and electromagnetic moments of Eu

The laser-induced resonance fluorescence in an atomic beam was used in order to measure the hyperfine splitting of the 4f ⁷ 6s ² and 4f^{7 6s6p} levels in ^151,153,155Eu isotopes. The hfs constants A and B of the unstable ¹⁵⁵Eu were determined for the first time: MHz, MHz and MHz. With these data and after corrections for second-order hyperfine structure perturbations the nuclear moments of ¹⁵⁵Eu were deduced: n.m. and b. In addition new and more precise values of the hfs constants of the excited state for the stable ^151,153Eu were obtained. They are as follows: MHz, MHz and MHz, MHz. The hyperfine anomalies % and % were extracted from the corrected hfs constants. Received 28 July 1999 and Received in final form 14 January 2000     

Nuclear charge radii changes of uranium and hafnium isotopes determined by laser spectroscopy

The present work reports measurements of isotope shifts and hyperfine structure in the optical spectra of two high-Z elements: Hf and U. The experiments are based on the observation of the resonance fluorescence in a well collimated atomic beam, excited by a tunable dye laser. The chains of the stable Hf isotopes and of^{233–236, 238}U have been investigated and changes in ms nuclear charge radii have been deduced. The results have been discussed from the point of view of nuclear structure in the investigated regions.     

Optical isotope shifts and changes in nuclear charge radii of stable Ti isotopes

Isotope shifts and hyperfine structures in three optical transitions of TiI have been investigated by using laser induced resonance fluorescence in a collimated atomic beam. From the isotope shifts data, changes of the mean square charge radii of the stable titanium isotopes have been determined for the first time. Using a combined analysis with muonic atom data on root mean square nuclear charge radii, improved model independent r ^21/2 values for the odd-even Ti isotopes have been obtained.     

Hyperfine splitting of the odd 4 F J o , 2 P J o and 4 S J o LaI multiplets

High resolution spectra of LaI lines recorded in the R6G region by laser-induced resonance fluorescence method show well resolved hyperfine structures. The analysis of the hyperfine structure of seven LaI transitions is presented here. It has allowed the deduction of magnetic dipole and electric quadrupole constants of all levels belonging to the excited odd parity multiplets: ⁴ F ^o (J = 3/2-9/2), ² P ^o (J = 1/2,3/2), and ⁴ S ^o (J = 3/2). Some of the results are new and some of them present improved values of the hyperfine splitting constants.     

Hyperfine Magnetic Anomaly in Atomic Spectra of Rare-Earth Elements

The constants of the hyperfine splitting in the atomic optical spectra of the rare-earth elements – Nd, Eu, Gd and Lu – were measured. The method of laser resonance fluorescence in the parallel atomic beam was used. The values of the hyperfine magnetic anomaly were determined from the comparision of magnetic dipole constant ratios of the neighbouring odd Z or N isotopes for the different atomic levels. The connection of these values and the parameters of atomic and nuclear structure is discussed. This revised version was published online in September 2006 with corrections to the Cover Date.     

Hyperfine splitting constants in the optical transition \boldsymbol{{4{f}^{7}} {6{s}^{2}} \;{^{8}{\rm S}_{7/2}} \to {4{f}^{7}} {6{s}6{p}}\; {^{6}{\rm P}_{5/2}} \ {\rm of} \ {^{151-155}{\rm Eu}}} isotopes and hyperfine anomaly

Using the method of laser-induced fluorescence in an atomic beam we have measured the hyperfine splitting constants, A and B, of the ground and excited states of the optical transition 4f ⁷6s ^{2 8}S $_{1/2}\to 4f^{7}$ 6s6p ⁶P_5/2 (564.58 nm) for ^151???155Eu isotopes. For all isotopes, the magnetic dipole constants of the ⁶P_5/2 atomic level are determined to a precision better than 0.04%. The A and B constants for the ground state ⁸S_7/2 of the radioactive ^152,154,155Eu were obtained for the first time with a precision better than 0.5%. Our data along with previous ground state hyperfine structure measurements for the stable europium isotopes allow us to determine the hyperfine anomaly for mentioned Eu isotopes.