Search results for " laser spectroscopy"
showing 10 items of 113 documents
Performance of a high repetition pulse rate laser system for in-gas-jet laser ionization studies with the Leuven laser ion source @ LISOL
2012
The Leuven Isotope Separator On-Line (LISOL) facility at the Cyclotron Research Center (CRC) Louvain-la-Neuve; The laser ionization efficiency of the Leuven gas cell-based laser ion source was investigated under on- and off-line conditions using two distinctly different laser setups: a low-repetition rate dye laser system and a high-repetition rate Ti:sapphire laser system. A systematic study of the ion signal dependence on repetition rate and laser pulse energy was performed in off-line tests using stable cobalt and copper isotopes. These studies also included in-gas-jet laser spectroscopy measurements on the hyperfine structure of 63Cu. A final run under on-line conditions in which the ra…
Resonance ionization schemes for high resolution and high efficiency studies of exotic nuclei at the CRIS experiment
2019
© 2019 This paper presents an overview of recent resonance ionization schemes used at the Collinear Resonance Ionization Spectroscopy (CRIS) setup located at ISOLDE, CERN. The developments needed to reach high spectral resolution and efficiency will be discussed. Besides laser ionization efficiency and high resolving power, experiments on rare isotopes also require low-background conditions. Ongoing developments that aim to deal with beam-related sources of background are presented. ispartof: Nuclear Instruments & Methods In Physics Research Section B-Beam Interactions With Materials And Atoms vol:463 pages:398-402 ispartof: location:SWITZERLAND, CERN, Geneva status: published
Theoretical and experimental study of primary radiation defects in KNbO3 perovskite crystals
2000
Abstract The results of large-scale computer simulations of point defects – F-type electron centers and hole polarons bound to a potassium vacancy – in perovskite KNbO3 crystals are presented. One-site polarons and two-site (molecular) polarons are expected to coexist, both are characterized by close absorption energies around 1 eV. The transient absorption spectra and decay kinetics observed after ns-pulsed electron beam irradiation have been measured for different KNbO3 crystals. The relaxation kinetics of the optical density vary considerably for different impurity concentrations and sample stoichiometries. Experimental data are discussed in the light of the presented calculations.
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.
Electromagnetic moments of scandium isotopes and $N=28$ isotones in the distinctive $0f_{7/2}$ orbit
2022
The electric quadrupole moment of $^{49}$Sc was measured by collinear laser spectroscopy at CERN-ISOLDE to be $Q_{\rm s}=-0.159(8)$ $e$b, and a nearly tenfold improvement in precision was reached for the electromagnetic moments of $^{47,49}$Sc. The single-particle behavior and nucleon-nucleon correlations are investigated with the electromagnetic moments of $Z=21$ isotopes and $N=28$ isotones as valence neutrons and protons fill the distinctive $0f_{7/2}$ orbit, respectively, located between magic numbers, 20 and 28. The experimental data are interpreted with shell-model calculations using an effective interaction, and ab-initio valence-space in-medium similarity renormalization group calcu…
Relaxation of electronic excitations in strontium titanate
2002
The transient absorption spectra and kinetics were studied for undoped, lead doped and high purity SrTiO 3 single crystals. The pulsed electron beam induced transient absorption is studied in all crystals. The strong absorption at 0.8 v eV was observed only in high purity SrTiO 3 . This absorption is suggested to arise from intrinsic electron polaron. The bound electron polarons are likely responsible for absorption band at 1.4 v eV. The main luminescence band under excitation pulse is observed at 2.75 v eV. The luminescence decay is faster than that of transient absorption.
The experimental observation of the potential barrier for self-trapped exciton decay into F-H pair in KCl-Na crystals
1995
Abstract The optical absorption induced by the electron pulse irradiation of Na+ doped KCl has been measured. Transient optical absorption band of FA centers was observed at 80 K (LNT). The temperature dependence of FA center formation was studied. It is proposed that the obtained activation energy originates from the potential barrier between the STE perturbed by the cation impurity and the nearest neighbour FA-H pair. The mechanism of the suppression of the defect formation by the monovalent cation impurity in alkali halide crystals is discussed.
Transient color centers in GGG crystals
2002
Electron pulse induced absorption and their decay kinetics have been investigated in samples of GGG crystals with different starting absorption spectra. It is shown that for all samples there appears a wide transient absorption (TA) band with two maxima in the region 14,000-17,000 v cm m 1 and 22,000-26,000 v cm m 1 . TA decay kinetics measurements in 14,000 v cm m 1 and 22,000 v cm m 1 are two-exponential (with half-time order several tens and several hundreds ns). Analyzing the obtained results, we can suppose that low and high energy TA bands are connected with the F + (or O m ) and F transient color centers (TCC) respectively.
Time-resolved spectroscopy of ZnWO4
2001
The luminescence spectra of ZnWO 4 excited by a pulsed electron beam, pulsed nitrogen laser and X-ray are studied. The luminescence decay kinetics are compared with transient absorption relaxation kinetics. Broad band transient absorption spectra are observed and it is shown that the slow decay component (∼14 μs at RT) of the transient absorption matches well with the luminescence decay therefore this absorption is due to the excited state absorption of the luminescence center.