Visible spectrum of highly charged ions: The forbidden optical lines of Kr, Xe, and Ba ions in the Ar I to Kr I isoelectronic sequence

2002 ◽  
Vol 80 (12) ◽  
pp. 1687-1700 ◽  
Author(s):  
J.R. Crespo López-Urrutia ◽  
P Beiersdorfer ◽  
K Widmann ◽  
V Decaux
Keyword(s):  
Electron Beam ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Visible Spectrum ◽  
Ion Traps ◽  
Highly Charged Ions ◽  
Excited Configuration ◽  
Experimental Conditions ◽  
Ion Cloud ◽  
Charged Ions

We present experimental data on visible transitions in highly charged ions observed in the Lawrence Livermore National Laboratory (LLNL) electron beam ion traps, including results from lines within the ground-state configuration and the first excited configuration. Measurements of lines produced by Kr (q = 11+ to 22+), Xe (q = 18+ to 35+), and Ba (q = 28+ to 36+) ions, corresponding mainly to 3sl 3pm 3dn configurations, were carried out. The ionization stages were determined experimentally by sweeping the electron beam energy over the ionization threshold of each species. We propose possible identifications for the lines with the help of simple atomic structure calculations. However, most observed lines remained unidentified, demonstrating that the understanding of visible spectra from highly charged ions, even if obtained under nearly "ideal" experimental conditions, is still in its infancy. These spectral data may be useful for the diagnostics of magnetically confined plasmas and may set the stage for future measurements of radiative lifetimes. In our experiments, we used the emission from visible lines to image the intersection of the electron beam with a beam of neutral atoms injected into the trap at a right angle as well as the ion cloud in the trap. Under some conditions, the diameter of the ion cloud may be an order of magnitude larger than that of the electron beam. PACS Nos.: 32.30Jc, 39.30+w, 52.59Rz

The visible spectrum of highly charged ions: A window to fundamental physics

2008 ◽  
Vol 86 (1) ◽  
pp. 111-123 ◽  
Author(s):  
J.R. Crespo López-Urrutia
Keyword(s):  
Transition Probabilities ◽  
Visible Spectrum ◽  
Ion Traps ◽  
Precise Determination ◽  
Highly Charged Ions ◽  
Visible Range ◽  
Electron Systems ◽  
Ionic Charge ◽  
Excellent Control ◽  
Charged Ions

The observation of forbidden transitions in the visible range was the first experimental sign of the existence of highly charged ions in nature. Such lines can nowadays be excited in electron beam ion traps with excellent control of the ionic charge state, allowing their identification and precise determination of wavelengths and transition probabilities. The accuracy achieved in such experiments has been central to the study of nuclear size effects and quantum electrodynamic contributions, which are drastically magnified in highly charged ions, thus enabling the study of the underlying fundamental interactions in few-electron systems. At the same time, forbidden lines can be used to probe conditions in high temperature plasmas present in both astrophysical and laboratory environments.PACS Nos.: 31.30.Jv, 32.10.Fn, 32.30.Jc, 96.60.Tf, 97.10.Ex, 32.60.+i, 32.70.Cs, 12.20.Fv, 42.50.Xa

Applications of EBITs to spectra of multi-electron ions: some solved and some unsolved problems

2008 ◽  
Vol 86 (1) ◽  
pp. 125-129 ◽  
Author(s):  
S Wu ◽  
R Hutton
Keyword(s):  
Electron Beam ◽  
Ion Traps ◽  
Highly Charged Ions ◽  
Spectral Features ◽  
Electron Systems ◽  
Charged Ions

Electron beam ion traps (EBITs) have, and will continue, to play an important role in unraveling spectral features in highly charged ions. In this paper, we will discuss two examples of EBIT-based spectroscopy of multi-electron systems, i.e., spectroscopy of N-, O- and F-like Ba and of Pm-like W. The EBIT work on W will be compared to a spectrum taken at the ASDEX upgrade Tokamak in Garching. PACS Nos.: 32.30.Jc, 32.30.Rj

X-ray wavelength survey of iron and nickel L-shell emission and resonance contributions to their intensities

2008 ◽  
Vol 86 (1) ◽  
pp. 191-198 ◽  
Author(s):  
M F Gu
Keyword(s):  
Electron Beam ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Ion Traps ◽  
Laboratory Astrophysics ◽  
X Ray ◽  
The Past ◽  
Line Identification

As part of the laboratory astrophysics program at the electron beam ion traps of the Lawrence Livermore National Laboratory, L-shell X-ray emission of Fe and Ni ions have been studied extensively in the past decade. In this paper, we review these experimental efforts in line identification and wavelength surveys of Fe and Ni L-shell emission and resonance contributions to their intensities. PACS Nos.: 52.72.+v, 52.20.–j, 34.80.Kw

scholarly journals The role of EBIT in X-ray laser research

2008 ◽  
Vol 86 (1) ◽  
pp. 19-23 ◽  
Author(s):  
J Nilsen
Keyword(s):  
Cross Sections ◽  
Ion Trap ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Highly Charged Ions ◽  
Index Of Refraction ◽  
X Ray ◽  
History Of ◽  
Level Of Understanding ◽  
Charged Ions

In the early 1980s, the X-ray laser program required a new level of understanding and measurements of the atomic physics of highly charged ions. The electron beam ion trap (EBIT) was developed and built at Lawrence Livermore National Laboratory (LLNL) as part of the effort to understand and measure the cross sections and wavelengths of highly charged ions. This paper explains some of the early history of EBIT and how it was used to help develop X-ray lasers. EBIT’s capability was unique and some of the experimental results obtained over the years, related to X-ray lasers, will be shown. As X-ray lasers have now become a table-top tool, new areas of research that involve understanding the index of refraction in partially ionized plasmas will be discussed. In addition, new areas where EBIT may be able to further contribute will be suggested.PACS Nos.: 52.38.–r, 52.25.Os, 52.70.–m, 42.55.Vc, 07.60.Ly, 29.30.Kv, 31.15.–p

Tungsten spectroscopy at the Livermore electron beam ion trap facility1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 571-580 ◽  
Author(s):  
J. Clementson ◽  
P. Beiersdorfer ◽  
G.V. Brown ◽  
M.F. Gu ◽  
H. Lundberg ◽  
...  
Keyword(s):  
Electron Beam ◽  
Ion Trap ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Ion Traps ◽  
Oscillator Strengths ◽  
Radiative Properties ◽  
Experimental Investigations ◽  
Fusion Plasma ◽  
International Colloquium

The utilization of tungsten spectroscopy for diagnostics of magnetically confined fusion plasmas requires the radiative properties of tungsten ions to be accurately known. At the Lawrence Livermore National Laboratory, a program to gather spectroscopic data on tungsten ions has been initiated with the purpose to study spectral signatures and identify candidate fusion plasma diagnostics. In this paper, an overview of recent results from the Livermore WOLFRAM spectroscopy project is presented, which includes experimental investigations at the EBIT-I and SuperEBIT electron beam ion traps. In particular, the spectra of highly charged M- and L-shell tungsten ions have been studied. These investigations cover energy measurements of n = 2 to n = 2, 3 transitions in Ne-like W64+ through Li-like W71+ ions and soft X-ray measurements of n = 3 to n = 3, 4 transitions in M-shell ions with emphasis on the Ni-like W46+ and Si-like W60+ through Na-like W63+ ions. The measurements are complemented by atomic-structure calculations and spectral modeling using the Flexible Atomic Code (FAC).

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