Filters
Results 1 - 10 of 22
Results 1 - 10 of 22.
Search took: 0.016 seconds
Sort by: date | relevance |
AbstractAbstract
[en] Electron-impact ionization cross sections σq,q+n have been measured for the reaction e + Smq+ → Sm(q+n) + (n + 1)e for single, double and triple ionization and initial charge states q = 1, 2, 3. The measurements have been performed using the dynamic crossed-beams technique in an energy range from the respective ionization threshold up to 1 keV. Furthermore, we have measured the single-ionization cross section for Sm12+ using the dynamic crossed- beams method and an energy-scan method. The cross sections are compared with semi-empirical formulae. In most cases the measured cross sections are described insufficiently. In the single-ionization cross section for Sm12+ a remarkable number of narrow structures resulting from resonant excitation with subsequent double-autoionization (REDA) are observed. (orig.)
Primary Subject
Source
HCI 2000: 10. international conference on the physics of highly charged ions; Berkeley, CA (United States); 30 Jul - 3 Aug 2000
Record Type
Journal Article
Literature Type
Conference; Numerical Data
Journal
Physica Scripta. T; ISSN 0281-1847;
; v. 92; p. 262-264

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Electron-impact ionization of ions is one of the most fundamental processes in every kind of plasma. Especially in high-temperature plasmas-whether in laboratory (nuclear fusion) or in astrophysics (atmosphere of stars)-atoms become ionized into multiply-charged ions by electron impact. The main purpose of authors' investigations is to unravel the contributions from different ionization mechanisms-like direct ionization (one-step process), excitation-autoionization (two-step process) and inner-shell Auger processes to the cross sections of single and multiple ionization of highly-charged ions. As the experimental database is still rather small, theoretical cross sections are often used for the calculation of different plasma parameters. Cross sections for ions with an outer 4f shell are usually small and experimental data is needed in order to test theories in that region. In the present study, the authors investigate the ionization of praseodymium ions, where cross section data has not been available up to now
Primary Subject
Record Type
Journal Article
Journal
Nuclear Physics Review; ISSN 1007-4627;
; v. 19(2); p. 144-146

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Employing the 'crossed-beams' technique, electron-impact ionization cross sections for the single-ionization of Wq+ ions in charge states q = 1...10 have been measured. The cross sections for the ionization of ions in charge states q ≥ 5 show significant contributions below the ground-state threshold caused by the ionization of ions in excited, long-lived metastable states in the parent ion beam. In the case of W6+, the measured cross section is completely dominated by metastable contributions. For ions in charge states q = 3...7, excitation-autoionization from the ground state as well as from excited, metastable states contributes strongly to the cross sections. This results in a strong underestimation of the measured cross sections by the semiempirical Lotz formula in the energy range between the ionization threshold and the cross section maximum. (Author)
Primary Subject
Record Type
Journal Article
Literature Type
Numerical Data
Journal
Journal of Physics. B, Atomic, Molecular and Optical Physics; ISSN 0953-4075;
; CODEN JPAPEH; v. 28(13); p. 2711-2721

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Aichele, K.; Arnold, W.; Braeuning, H.; Hathiramani, D.; Scheuermann, F.; Trassl, R.; Salzborn, E., E-mail: e.salzborn@strz.uni-giessen.de2003
AbstractAbstract
[en] Using the dynamic crossed-beams method, the following absolute cross sections σq,q+n for single (n=1), double (n=2) and triple (n=3) ionization by electron impact have been measured for the reaction e-+Prq+→Pr(q+n)++(n+1)e- n=1: σ2,3 σ3,4σ4,5 σ6,7 σ7,8 σ8,9 σ11,12 n=2: σ1,3 σ2,4 σ3,5 σ4,6 n=3: σ1,4 σ2,5 σ3,6 The measurements have been performed in an energy range from the respective threshold up to 1 keV. For the single-ionization cross sections, contributions from excitation-autoionization processes increase with increasing charge state of the parent ion. As no theoretical calculations on praseodymium ions exist, these cross sections are compared to the semi-empirical Lotz formula [Zeitschrift fuer Physik 232 (1970) 101]. Where contributions of indirect inner-shell processes to the cross section are expected, we conducted energy-scan measurements with high energy resolution. For multiple ionization, no theoretical calculations on praseodymium ions exist. Therefore, the measured cross sections were compared to the semi-empirical formulae by Belenger et al. [J. Phys. B: At. Mol. Opt. Phys. 30 (1997) 2667] and Fisher et al. [J. Phys. B: At. Mol. Opt. Phys. 28 (1995) 3027]
Primary Subject
Source
11. international conference on the physics of highly charged ions; Caen (France); 1-6 Sep 2002; S0168583X03005652; Copyright (c) 2003 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Record Type
Journal Article
Literature Type
Conference
Journal
Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms; ISSN 0168-583X;
; CODEN NIMBEU; v. 205(1-4); p. 437-443

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Stenke, M.; Aichele, K.; Hathiramani, D.; Hofmann, G.; Steidl, M.; Voelpel, R.; Salzborn, E.
Atomic and plasma-material interaction data for fusion. V. 61995
Atomic and plasma-material interaction data for fusion. V. 61995
AbstractAbstract
[en] Electron impact ionization cross sections for the single and multiple ionization of tungsten ions have been measured by employing the ''crossed-beams'' technique. For Wq+ ions in charge states q=1...10 cross sections for single ionisation were determined. For ions in charge states q=3...7, excitation-autoionization from the ground state as well as from excited, metastable states strongly contributes to the cross sections. This results in a strong underestimation of the measured cross sections compared to the semiempirical Lotz formula in the energy range between the ionization threshold and the cross section maximum. The ionization cross section for Wq+ ions was measured in the case of double ionization for q=1...6 and of triple ionization up to q=4. The multiple ionization cross sections indicate no considerable contributions of indirect processes. (author). 17 refs, 10 figs, 1 tab
Primary Subject
Secondary Subject
Source
International Atomic Energy Agency, Vienna (Austria); Nuclear Fusion; (Suppl.6); 264 p; 1995; p. 51-58; IAEA; Vienna (Austria)
Record Type
Book
Literature Type
Numerical Data
Country of publication
Reference NumberReference Number
Related RecordRelated Record
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Short communication
Original Title
Fragmentation von positiv geladenen Fulleren-Ionen durch Elektronenstoss
Primary Subject
Source
Spring meeting of Fachverbaende Atomphysik, Kurzzeitphysik, Massenspektrometrie, Molekuelphysik, Plasmaphysik and Quantenoptik of Deutsche Physikalische Gesellschaft e.V. (DPG) with physics and book exhibition; Fruehjahrstagung der Fachverbaende Atomphysik, Kurzzeitphysik, Massenspektrometrie, Molekuelphysik, Plasmaphysik und Quantenoptik der Deutschen Physikalischen Gesellschaft e.V. (DPG) mit Physik- und Buchausstellung; Mainz (Germany); 3-6 Mar 1997
Record Type
Journal Article
Literature Type
Conference
Journal
Verhandlungen der Deutschen Physikalischen Gesellschaft; ISSN 0420-0195;
; CODEN VDPEAZ; v. 32(3); p. 186

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Employing the animated crossed-beams technique, absolute cross sections for electron impact single ionization of the iron isonuclear sequence are measured for charge states q=1-6 for electron energies from threshold up to 1 keV, as well as for the intermediate charge states q=9,10 up to an electron energy of 5 keV. The cross sections observed for Feq+ ions in charge states q=1-4, 9 and 10 show a significant ionization signal below the respective ground state threshold resulting from ions in excited, long-lived metastable states in the parent ion beam. In the case of Fe5+ and Fe6+ no metastable components are found. The experimental results are in good agreement with the theoretical predictions if excitation-autoionization processes are taken into account. Our measured cross sections are also in good agreement with experimental results of other groups. (author)
Primary Subject
Source
Available online at the Web site for the Journal of Physics. B, Atomic, Molecular and Optical Physics (ISSN 1361-6455) http://www.iop.org/; Country of input: Pakistan; 29 refs
Record Type
Journal Article
Journal
Journal of Physics. B, Atomic, Molecular and Optical Physics; ISSN 0953-4075;
; v. 32(15); p. 3627-3639

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
External URLExternal URL
AbstractAbstract
[en] Electron impact ionization cross sections σq,q+n for gallium ions have been measured for the reaction e + Gaq+ → Ga(q+n)+ + (n + 1)e for single (n = 1, q = 1, 3, 8) and triple (n = 3, q = 3, 4) ionization. The measurements have been performed using the crossed-beams technique in an energy range from the respective ionization threshold up to 1 keV, partly up to 6 keV. The cross sections for single ionization of ions in the charge state q = 1 and 3 show contributions below the ground state threshold caused by ionization of ions in excited, long-lived states in the parent ion beam. The cross sections are compared with the semiempirical Lotz formula. The cross section for Ga4+ triple ionization shows contributions from inner-shell processes. Semiempirical formulae are in good agreement with the experimental data only at energies below the cross section maximum. (orig.)
Primary Subject
Source
9. international conference on the physics of highly-charged ions (HCI-9); Bensheim (Germany); 9-14 Sep 1998; 12 refs.
Record Type
Journal Article
Literature Type
Conference
Journal
Physica Scripta. T; ISSN 0281-1847;
; v. 80(pt.B); p. 287-288

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Absolute cross sections σq,q+n for the multiple ionization of Cq+, Nq+ and Oq+ ions were measured for the reactions: e + Aq+ → A(q+n)+ + (n + 1)e. The measurements were performed for electron energies up to 6.5 keV using the animated crossed-beams method at the Giessen electron-ion crossed-beams set-up. K-shell ionization with subsequent autoionization or even double-autoionization strongly contributes to the cross sections. (orig.)
Primary Subject
Source
9. international conference on the physics of highly-charged ions (HCI-9); Bensheim (Germany); 9-14 Sep 1998; 10 refs.
Record Type
Journal Article
Literature Type
Conference
Journal
Physica Scripta. T; ISSN 0281-1847;
; v. 80(pt.B); p. 285-286

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Using the crossed-beams technique, cross sections for electron impact double ionization of Feq+ ions in charge states q=1-6 (except 2) are measured in the energy range from the respective ionization thresholds up to 1 keV, partly up to 5 keV. The data for Fe4+, Fe5+ and Fe6+ show significant contributions from inner-shell processes. Using a high-resolution energy-scan technique, we study narrow resonances in the cross sections for Fe4+ and Fe5+. Besides contributions from excitation-autoionization processes, a remarkable number of structures arising from resonant-excitation triple-autoionization processes are observed. The results are compared with the scaling laws of Fisher et al and the semiempirical formula published by Shevelko and Tawara, respectively. (author)
Primary Subject
Source
Available online at the Web site for the Journal of Physics. B, Atomic, Molecular and Optical Physics (ISSN 1361-6455) http://www.iop.org/; Country of input: Pakistan; 20 refs
Record Type
Journal Article
Journal
Journal of Physics. B, Atomic, Molecular and Optical Physics; ISSN 0953-4075;
; v. 32(15); p. 3641-3649

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
External URLExternal URL
1 | 2 | 3 | Next |