| 1. |
- Rodriguez, L. , V, et al.
(författare)
-
Doubly-magic character of Sn-132 studied via electromagnetic moments of( 13)(3)Sn
- 2020
-
Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 102:5
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first measurement of the magnetic dipole and electric quadrupole moment of the exotic nucleus Sn-133 by high-resolution laser spectroscopy at ISOLDE/CERN. These, in combination with state-of-the-art shell-model calculations, demonstrate the single-particle character of the ground state of this short-lived isotope and, hence, the doubly-magic character of its immediate neighbor Sn-132. The trend of the electromagnetic moments along the N = 83 isotonic chain, now enriched with the values of tin, are discussed on the basis of realistic shell-model calculations.
|
|
| 2. |
- Sampaio, J. M., et al.
(författare)
-
Simulation of (125) I Auger emission spectrum with new atomic parameters from MCDHF calculations
- 2022
-
Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier. - 0022-4073 .- 1879-1352. ; 277
-
Tidskriftsartikel (refereegranskat)abstract
- New 125 I atomic decay emission data of medical interest are presented. The calculations are based on two atomic structure codes that implement the multi-configuration Dirac-Hartree-Fock method. Radiative and non-radiative ransition rates are calculated in this method and then used to generate the atomic deexcitation cascade. Subshell transition rates, level widths and fluorescence yields are compared to the Evaluated Atomic Data Library. Coster-Kronig and Auger electron emission yields are also compared with results from other authors. The comparison with the experimental electron emission spectrum shows that the new calculations can reproduce very well the structure of the K-LL Auger electron peaks and improve the description of the M Auger peaks below 300 eV. The 125 I dose-point kernel is also simulated using the new data, resulting in higher values below 10 nm when compared those obtained with the Evaluated Atomic Data Library.
|
|
| 3. |
- Ekman, Jörgen, et al.
(författare)
-
Retention of Pb isotopes in glass surfaces for retrospective assessment of radon exposure
- 2006
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier. - 0168-583X .- 1872-9584. ; 249:1-2, s. 544-547
-
Tidskriftsartikel (refereegranskat)abstract
- In recent years there has been increasing interest in radio-epidemiological techniques to retrospectively measure the radon dose exposure by determining the activity of 210Pb, the longest-lived 222Rn progeny, in glass surface layers. In this study the diffusion of 39 keV 209Pb+ ions implanted into glass using the IGISOL facility has been studied under conditions that mimic the recoil implantation of 210Pb from 222Rn. The resulting depth distributions of 209Pb were then measured after heat treatment in vacuum at different temperatures by a sputter erosion technique. The diffusion coefficient could be described by an Arrhenius equation D = D0exp(−H/kT) where and H = 2.81 ± 0.11 eV. No statistically significant loss of 209Pb from the sample was observed for annealing between 470 and 600 °C.
|
|
| 4. |
- Inoyatov, A. Kh, et al.
(författare)
-
The KLM plus KLN Auger electron spectrum of rubidium in different matrices
- 2017
-
Ingår i: Journal of Physics B. - : Institute of Physics Publishing (IOPP). - 0953-4075 .- 1361-6455. ; 50:15
-
Tidskriftsartikel (refereegranskat)abstract
- The KLM + KLN Auger electron spectrum of rubidium (Z = 37) emitted in the electron capture decay of radioactive Sr-83 in a polycrystalline platinum matrix and also Sr-85 in polycrystalline platinum and carbon matrices as well as in an evaporated layer onto a carbon backing were experimentally studied in detail for the first time using a combined electrostatic electron spectrometer. Energies, relative intensities, and natural widths of fifteen basic spectrum components were determined and compared with both theoretical predictions and experimental data for krypton (Z = 36). Relative spectrum line energies obtained from the semi-empirical calculations in intermediate coupling scheme were found to agree within 3 sigma with the measured values while disagreement with experiment exceeding 3s was often observed for values obtained from our multiconfiguration Dirac-Hartree-Fock calculations. The absolute energy of the dominant spectrum component given by the semi-empirical approach agrees within 1 sigma with the measured value. Shifts of +(0.2 +/- 0.2) and -(1.9 +/- 0.2) eV were measured for the dominant KLM spectrum components between the 85Sr sources prepared by vacuum evaporation on and implanted into the carbon foil, respectively, relative to 85Sr implanted into the platinum foil. A value of (713 +/- 2) eV was determined for the energy difference of the dominant components of the KLM + KLN Auger electron spectra of rubidium and krypton generated in the polycrystalline platinum matrix. From the detailed analysis of the measured data and available theoretical results, the general conclusion can be drawn that the proper description of the KLM + KLN Auger electron spectrum for Z around 37 should still be based on the intermediate coupling of angular momenta taking into account relativistic effects.
|
|
| 5. |
- Jönsson, Per, et al.
(författare)
-
Relativistic CI calculations of spectroscopic data for the 2p6 and 2p53l configurations in Ne-like ions between Mg III and Kr XXVII
- 2014
-
Ingår i: Atomic Data and Nuclear Data Tables. - : Elsevier. - 0092-640X .- 1090-2090. ; 100:1, s. 1-154
-
Tidskriftsartikel (refereegranskat)abstract
- Energies, E1, M1, E2, M2 transition rates, oscillator strengths, and lifetimes from relativistic configuration interaction calculations are reported for the states of the 2p6, 2p53s, 2p53p, and 2p53d, configurations in all Ne-like ions between Mg III and Kr XXVII. Core–valence and core–core correlation effects are accounted for through single and double excitations to increasing sets of active orbitals. The Breit interaction and leading quantum electrodynamic effects are included as perturbations. The results are compared with experiments and other recent benchmark calculations. In Mg III, Al IV, Si V, P VI, S VII, and Ar IX, for which experimental energies are known to high accuracy, the mean error in the calculated energies is only 0.011%.
|
|
| 6. |
- Laitinen, Mikko, et al.
(författare)
-
Mobility determination of lead isotopes in glass for retrospective radon measurements
- 2008
-
Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 131:3, s. 212-216
-
Tidskriftsartikel (refereegranskat)abstract
- In retrospective radon measurements, the 22-y half life of Pb-210 is used as an advantage. Pb-210 is often considered to be relatively immobile in glass after alpha recoil implanted by Rn-222 progenies. The diffusion of Pb-210 could, however, lead to uncertain wrong retrospective radon exposure estimations if Pb-210 is mobile and can escape from glass, or lost as a result of cleaning-induced surface modification. This diffusion was studied by a radiotracer technique, where Pb-209 was used as a tracer in a glass matrix for which the elemental composition is known. Using the ion guide isotope separator on-line technique, the Pb-209 atoms were implanted into the glass with an energy of 39 keV. The diffusion profiles and the diffusion coefficients were determined after annealing at 470-620 degrees C and serial sectioning by ion sputtering. In addition, the effect of surface cleaning on diffusion was tested. From the Arrhenius fit, the activation enthalpy (H) was determined, which is equal to 3.2 +/- 0.2 eV, and also the pre-exponential factor D-0, in the order of 20 m(2)s(-1). This result confirms the assumption that over a time period of 50 y Pb-209 (and Pb-210) is effectively immobile in the glass. The boundary condition obtained from the measurements had the characteristic of a sink, implying loss of Pb-209 in the topmost surface at high temperatures.
|
|
| 7. |
- Li, Wenxian, et al.
(författare)
-
Multiconfiguration Dirac-Hartree-Fock calculations of Lande g-factors for ions of astrophysical interest : B II, C I-IV, Al I-II, Si I-IV, P II, S II, Cl III, Ar IV, Ca I, Ti II, Zr III, and Sn II
- 2020
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 639
-
Tidskriftsartikel (refereegranskat)abstract
- Aims. The Lande g-factor is an important parameter in astrophysical spectropolarimetry, used to characterize the response of a line to a given value of the magnetic field. The purpose of this paper is to present accurate Lande g-factors for states in B II, C I-IV, Al I-II, Si I-IV, P II, S II, Cl III, Ar IV, Ca I, Ti II, Zr III, and Sn II.Methods. The multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction methods, which are implemented in the general-purpose relativistic atomic structure package GRASP2K, are employed in the present work to compute the Lande g-factors for states in B II, C I-IV, Al I-II, Si I-IV, P II, S II, Cl III, Ar IV, Ca I, Ti II, Zr III, and Sn II. The accuracy of the wave functions for the states, and thus the accuracy of the resulting Lande g-factors, is evaluated by comparing the computed excitation energies and energy separations with the National Institute of Standards and Technology (NIST) recommended data.Results. All excitation energies are in very good agreement with the NIST values except for Ti II, which has an average difference of 1.06%. The average uncertainty of the energy separations is well below 1% except for the even states of Al I; odd states of Si I, Ca I, Ti II, Zr III; and even states of Sn II for which the relative differences range between 1% and 2%. Comparisons of the computed Lande g-factors are made with available NIST data and experimental values. Analysing the LS-composition of the wave functions, we quantify the departures from LS-coupling and summarize the states for which there is a difference of more than 10% between the computed Lande g-factor and the Lande g-factor in pure LS-coupling. Finally, we compare the computed Lande g-factors with values from the Kurucz database.
|
|
| 8. |
- Tashiro, M., et al.
(författare)
-
Macro-coherent radiative emission of neutrino pair between parity-even atomic states
- 2019
-
Ingår i: European Physical Journal C. - : Springer. - 1434-6044 .- 1434-6052. ; 79:11
-
Tidskriftsartikel (refereegranskat)abstract
- A new scheme to determine the neutrino mass matrix is proposed using atomic de-excitation between two states of a few eV energy spacing. The determination of the smallest neutrino mass of the order of 1 meV and neutrino mass type, Majorana or Dirac, becomes possible, if one can coherently excite more than 1 gram of atoms using two lasers.
|
|
| 9. |
- Wang, Kai, et al.
(författare)
-
Extended calculations of energy levels, radiative properties, A(J), B-J hyperfine interaction constants, and Lande g(J)-factors for oxygen-like Kr XXIX
- 2017
-
Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier. - 0022-4073 .- 1879-1352. ; 194, s. 108-112
-
Tidskriftsartikel (refereegranskat)abstract
- Using the multiconfiguration Dirac-Fock method and the second-order many-body perturbation theory method, highly accurate calculations are performed for the lowest 344 fine-structure levels arising from the 2s(2)2p(4), 2s2p(5), 2p(6), 2s(2)2p(3)3s, 2s(2)2p(3)3p, 2s(2)2p(3)3d, 2s2p(4)3s, 2s2p(4)3p, 2s2p(4)3d, 2p(5)3s, 2p(5)3p, 2p(5)3d, 2s(2)2p(3)4s, 2s(2)2p(3)4p, 2s(2)2p(3)4d, 2s(2)2p(3)4f, and 2s2p(4)4s configurations in O-like Kr XXIX. Complete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Lande g(J)-factors, and E1, M1, E2, M2 transition rates, line strengths, and oscillator strengths among these 344 levels are obtained. Comparisons are made between our two different sets of results, as well as with the other available experimental and theoretical values. For O-like Kr only a few levels have been experimentally established. The accuracy of our calculated energies is however high enough to facilitate identifications of observed lines involving the n = 3,4 levels. The calculated data are also useful for modeling and diagnosing fusion plasmas. (C) 2017 Elsevier Ltd. All rights reserved.
|
|
| 10. |
- Wang, Kai, et al.
(författare)
-
Extended Calculations of Spectroscopic Data : Energy Levels, Lifetimes, and Transition Rates for O-like Ions from Cr XVII to ZnXXIII
- 2017
-
Ingår i: Astrophysical Journal Supplement Series. - : Bibliopolis, Edizioni di Filosofia e Scienze. - 0067-0049 .- 1538-4365. ; 229:2
-
Tidskriftsartikel (refereegranskat)abstract
- Employing two state-of-the-art methods, multiconfiguration Dirac-Hartree-Fock and second-order many-body perturbation theory, the excitation energies and lifetimes for the lowest 200 states of the 2 s(2)2p(4), 2s2p(5), 2p(6), 2s(2)2p(3)3s, 2s(2)2p(3)3p, 2s(2)2p(3)3d, 2s(2)p(4)3s, 2s2p(4)3p, and 2s2p(4)3d configurations, and multipole (electric dipole (E1), magnetic dipole (M1), and electric quadrupole (E2)) transition rates, line strengths, and oscillator strengths among these states are calculated for each O-like ion, from Cr XVII to Zn XXIII. Our two data sets are compared with the National Institute of Standards and Technology and CHIANTI compiled values, and previous calculations. The data are accurate enough for identification and deblending of new emission lines from the Sun and other astrophysical sources. The amount of high-accuracy data is significantly increased for the n. =. 3 states of several O-like ions of astrophysical interest, where experimental data are very scarce.
|
|
