Polarization and anisotropic emission of K-shell radiation from heavy few electron ions1This article 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. 513-519 ◽  
Author(s):  
D.B. Thorn ◽  
A. Gumberidze ◽  
S. Trotsenko ◽  
D. Banaś ◽  
H. Beyer ◽  
...  
Keyword(s):  
Oscillator Strengths ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Excitation Process ◽  
International Colloquium ◽  
X Ray ◽  
Uranium Ions ◽  
Gas Target ◽  
Laboratory Plasmas ◽  
Gas Targets

The population of magnetic sublevels in hydrogen-like uranium ions has been investigated in relativistic ion–atom collisions by observing the subsequent X-ray emission. Using the gas target at the experimental storage ring facility we observed the angular emission of Lyman-α radiation from hydrogen-like uranium ions. The alignment parameter for three different interaction energies was measured and found to agree well with theory. In addition, the use of different gas targets allowed for the electron-impact excitation process to be observed.

Polarization of the Lyman-α1 X-ray line emitted by hydrogen-like Ti21+, Ar17+, and Fe25+ ions excited by electron impact1This 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. 503-507 ◽  
Author(s):  
Christopher J. Bostock ◽  
Dmitry V. Fursa ◽  
I. Bray
Keyword(s):  
Electron Impact ◽  
Theoretical Calculations ◽  
Oscillator Strengths ◽  
Special Issue ◽  
Close Coupling ◽  
International Colloquium ◽  
X Ray ◽  
10Th International Colloquium ◽  
Laboratory Plasmas ◽  
Theory And Experiment

We present a review of the relativistic convergent close-coupling (RCCC) method and describe how it has been used to resolve the discrepancy between theory and experiment for the polarization of the Lyman-α1 X-ray line emitted by hydrogen-like Ti21+, Ar17+, and Fe25+ ions excited by electron impact. We find that taking account of Breit relativistic corrections is important to resolve the discrepancy between experiment and theoretical calculations.

Kα transition probabilities for platinum and uranium ions for possible X-ray biomedical applications1This article 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. 483-494 ◽  
Author(s):  
Sultana N. Nahar ◽  
Anil K. Pradhan ◽  
Sara Lim
Keyword(s):  
Radiative Decay ◽  
Transition Probabilities ◽  
High Energy ◽  
Decay Rates ◽  
Oscillator Strengths ◽  
X Rays ◽  
International Colloquium ◽  
X Ray ◽  
Enhanced Production ◽  
Uranium Ions

Platinum compounds, such as cisplatin and other high-Z materials, are increasingly common in biomedical applications. The absorption and emission of high-energy X-rays can occur via the 1s–2p Kα transitions in ions of heavy elements involving deep inner-shells. Oscillator strengths (f), line strengths (S), and radiative decay rates (A), for the 1s–2p transitions for the nine ionic states from hydrogen-like to fluorine-like, are presented for platinum and uranium. For platinum ions the Kα transitions are found to be in the hard X-ray region, 64–71 keV (0.18–0.17 Å), and for uranium ions they are in the range 94–105 keV (0.12–0.13 Å). Since the number of electrons in each ionic state of the element is different, the number of Kα transitions varies considerably. While there are two 1s–2p transitions (1s 2S1/2–2p [Formula: see text]) in H-like ions, there are 2, 6, 2, 14, 35, 35, and 14 transitions in He-like, Li-like, Be-like, B-like, C-like, N-like, and O-like ions, respectively, for a total of 112 Kα transitions for each element. These include both types of electric dipole (E1) allowed transitions, same-spin multiplicity and intercombination. The former dipole allowed transitions are in general strong; their radiative decay rates are of the order of A ∼ 1016 s–1. However, there are also many weaker transitions. We demonstrate the importance of these Kα transitions, as they appear as resonances in photo-ionization, which is relevant to the enhanced production of Auger electrons for possible radiation diagnostics and therapy.

Laser gain calculations for soft X-ray and XUV radiation emitted from copper-like ions by electron collisional pumping

2016 ◽  
Vol 94 (10) ◽  
pp. 967-974
Author(s):  
Mohamed A. Sayed ◽  
Sami H. Allam ◽  
Tharwat M. El-Sherbini
Keyword(s):  
Transition Probabilities ◽  
Calculated Data ◽  
Level Population ◽  
Oscillator Strengths ◽  
Impact Excitation ◽  
Rate Coefficients ◽  
Electron Impact Excitation ◽  
Population Densities ◽  
Excitation Rate ◽  
X Ray

Electron impact excitation rate coefficients, level population densities, and gain coefficients for six excited ions with Z = 51, 52, 53, 54, 55, 56 in the copper isoelectronic sequence have been calculated. The electron collisional excitation rate coefficients are calculated according to the analytical formulas of Vriens and Smeets. Fine structure energy levels, transition probabilities, and oscillator strengths needed in the calculations have been calculated using Cowan atomic structure code with relativistic corrections for [Ar]3d10nl with n = 4–7 and l = 0–6. The level population densities are calculated by solving the coupled rate equations involving 30 levels. Positive gain coefficients of the possible emitted lines are obtained at three selected electron temperatures, namely 1/4, 1/2, and 3/4 of the ionization energy. The present calculated data show promising values for the production of soft X-ray and XUV laser by collisional pumping for the transitions 5p–5s and 6d–5f with wavelengths between 108 and 571 Å. The values of the maximum gain coefficient are found to increase with atomic number and their order of magnitude ranges from102to 104cm−1.

scholarly journals Electron-impact excitation of H-like Cr, Mn, Fe, Co, and Ni for applications in modeling X-ray astrophysical sources

2011 ◽  
Vol 526 ◽  
pp. A115 ◽  
Author(s):  
C. Malespin ◽  
C. P. Ballance ◽  
M. S. Pindzola ◽  
M. C. Witthoeft ◽  
T. R. Kallman ◽  
...  
Keyword(s):  
Electron Impact ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
X Ray
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