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

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

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

scholarly journals QED Theory of Transition Probabilities and Line Profiles in Highly Charged Ions

2002 ◽  
Vol 302 (1) ◽  
pp. 22-58 ◽  
Author(s):  
L.N. Labzowsky ◽  
A. Prosorov ◽  
A.V. Shonin ◽  
I. Bednyakov ◽  
G. Plunien ◽  
...  
Keyword(s):  
Transition Probabilities ◽  
Highly Charged Ions ◽  
Line Profiles ◽  
Charged Ions

scholarly journals Effect of Voltage Pulse Width and Synchronized Substrate Bias in High-Power Impulse Magnetron Sputtering of Zirconium Films

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 7
Author(s):  
Chin-Chiuan Kuo ◽  
Chun-Hui Lin ◽  
Jing-Tang Chang ◽  
Yu-Tse Lin
Keyword(s):  
Growth Rate ◽  
Magnetron Sputtering ◽  
High Power ◽  
Pulse Width ◽  
Film Growth ◽  
Highly Charged Ions ◽  
Argon Pressure ◽  
Hexagonal Prism ◽  
Film Growth Rate ◽  
Charged Ions

The Zr film microstructure is highly influenced by the energy of the plasma species during the deposition process. The influences of the discharge pulse width, which is the key factor affecting ionization of sputtered species in the high-power impulse magnetron sputtering (HiPIMS) process, on the obtained microstructure of films is investigated in this research. The films deposited at different argon pressure and substrate biasing are compared. With keeping the same average HiPIMS power and duty cycle, the film growth rate of the Zr film decreases with increasing argon pressure and enhancing substrate biasing. In addition, the film growth rate decreases with the elongating HiPIMS pulse width. For the deposition at 1.2 Pa argon, extending the pulse width not only intensifies the ion flux toward the substrate but also increases the fraction of highly charged ions, which alter the microstructure of films from individual hexagonal prism columns into a tightly connected irregular column. Increasing film density leads to higher hardness. Sufficient synchronized negative substrate biasing and longer pulse width, which supports higher mobility of adatoms, causes the preferred orientation of hexagonal α-phase Zr films from (0 0 0 2) to (1 0 1¯ 1). Unlike the deposition at 1.2 Pa, highly charged ions are also found during the short HiPIMS pulse width at 0.8 Pa argon.

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