X-RAY PRODUCTION, INNER SHELL IONIZATION AND READING’S THEOREM IN ION · ATOM COLLISIONS

1992 ◽  
Vol 02 (03) ◽  
pp. 197-209
Author(s):  
KEIZO ISHII
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
X Rays ◽  
Ionization Cross ◽  
Heavy Charged Particles ◽  
X Ray ◽  
Inner Shell Ionization ◽  
Ionization Cross Sections ◽  
Shell Ionization

When a solid or gaseous target is bombarded with heavy charged particles, inner shell electrons of target atoms are ionized and characteristic x rays are produced. We can easily observe these x rays with a Si(Li) detector and derive inner-shell ionization cross section from the x-ray production cross sections. In this paper, we make a review of x-ray production, inner shell ionization and Reading’s theorem in light ion·atom collisions. This theorem is one of the most important ones in the ion·atom collision physics and permits precise discussion on comparison between experimental inner-shell ionization cross sections obtained with a Si(Li) detector and the calculations based on usual theories where the incident particle is assumed to interact with only one electron in an atom and the presence of other electrons is ignored.

Measurements of Electron Impact K-shell Ionization Cross Sections of Cr21+ Ions

2021 ◽  
Author(s):  
David Vogel ◽  
Peter Beiersdorfer ◽  
Keith Wong ◽  
Ron Zasadzinski ◽  
Ming Feng Gu
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
X Rays ◽  
Distorted Wave ◽  
Ionization Cross ◽  
X Ray ◽  
Relative Cross Section ◽  
Inner Shell Ionization ◽  
Ionization Cross Sections ◽  
Shell Ionization

We present relative cross section measurements of the inner-shell ionization of highly charged chromium ions by high-energy (7-30 keV) electrons. The measurements use a technique based on high-resolution x-ray spectroscopy, which correlates ionization events with K∝ decay x rays. Moreover, the measurements show that inner-shell ionization only affects the strength of the heliumlike 1s2s 3S1 -> 1s2 1S0 forbidden line. The cross sections inferred for Li-like Cr21+ agree well with distorted wave calculations.

MATRIX EFFECTS ON K-SHELL IONIZATION CROSS SECTIONS IN Al/Si ALLOYS

2002 ◽  
Vol 12 (01n02) ◽  
pp. 1-5
Author(s):  
M. NEKAB ◽  
Ch. HEITZ
Keyword(s):  
Cross Sections ◽  
Matrix Effects ◽  
Production Cross ◽  
Heavy Ion ◽  
Double Scattering ◽  
Scattering Mechanism ◽  
Ionization Cross ◽  
X Ray ◽  
Ionization Cross Sections ◽  
Shell Ionization

Thick targets consisting in Al/Si alloys were bombarded with 1.0 to 5.0 MeV Ar ions. The K X-ray production cross sections were deduced from the measured yields by using the Merzbacher-Lewis formula extended to heavy ion bombardment. The density dependence on the K X-ray production cross sections of Al and Si was observed. This phenomena can be interpreted within the molecular orbital double-scattering mechanism.

K-shell ionization cross sections of K and Lα X-ray production cross sections of I by 10–30 keV electron impact

2012 ◽  
Vol 90 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Y. Wu ◽  
Z. An ◽  
Y.M. Duan ◽  
M.T. Liu ◽  
X.P. Ouyang
Keyword(s):  
Experimental Data ◽  
Electron Impact ◽  
Cross Sections ◽  
Production Cross ◽  
Carbon Substrate ◽  
Ionization Cross ◽  
X Ray ◽  
Pure Carbon ◽  
Ionization Cross Sections ◽  
Shell Ionization

The absolute K-shell ionization cross sections of K and Lα X-ray production cross sections of I by 10–30 keV electron impact have been measured. The target was prepared by evaporating a thin film of compound KI to a thick pure carbon substrate. The effects of multiple scattering of electrons penetrating the target films, electrons reflected from the thick pure carbon substrates and bremsstrahlung photons produced when incident electrons impacted on the targets were corrected by using the Monte Carlo method. For K K-shell and I L-shell X-ray characteristic peaks, the spectra were fitted using the spectrum-fitting program ALLFIT to extract the Kα and Kβ peak counts more accurately for element K, and Lα peak counts for element I. The experimental results were compared with some theoretical results developed recently and available experimental data from the literature. The experimental data for I L-shell X-ray production cross sections by 10–30 keV electron impact are given here for the first time.

Inner-Shell Ionization Cross Sections

1990 ◽  
Vol 48 (2) ◽  
pp. 6-7
Author(s):  
C. J. Powell
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Relativistic Correction ◽  
Bethe Equation ◽  
Ionization Cross ◽  
Section Data ◽  
Inner Shell Ionization ◽  
Ionization Cross Sections ◽  
Image Position ◽  
Shell Ionization

Values of cross sections for ionization of inner-shell electrons by electron impact are required for electron probe microanalysis, Auger-electron spectroscopy, and electron energy-loss spectroscopy. The present author has reviewed measurements and calculations of inner-shell ionization cross sections. This paper is an update and summary of these previous reviews.It is convenient to start with the Bethe equation for inner-shell ionization cross sections which is frequently used (and misused) in x-ray microanalysis:(1)where σnℓ is the cross section for ionization of the nℓ shell with binding energy Enℓ by incident electrons of energy E. The terms bnℓ and cnℓ are the Bethe parameters discussed further below. It has been assumed in the derivation of Eq. (1) that E ≫ Enℓ ; this requirement will also be discussed. Finally, it has been assumed here that E is low enough (≲50 keV) so that a relativistic correction is unnecessary.The extent to which a given set of measured or calculated cross-section data is consistent with Eq. (1) can be determined from a Fano plot in which σnℓE is plotted versus ℓnE; if such a plot is linear, Eq. (1) is consistent with the data and values of the Bethe parameters can be easily derived.

X-Ray Production Cross Sections for Ti, Co, Ge, Rb and Sn by 16 - 44 Mev Oxygen Ion Bombardment

1973 ◽  
Vol 17 ◽  
pp. 445-456
Author(s):  
R. F. Chaturvedi ◽  
J. L. Duggan ◽  
T. J. Gray ◽  
C. C. Sachtleben ◽  
J. Lin
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
X Rays ◽  
X Ray ◽  
Oxygen Ions ◽  
Oxygen Ion ◽  
Theoretical Predictions ◽  
Ionization Cross Sections ◽  
Binary Encounter Approximation ◽  
Shell Ionization

AbstractAbsolute K-shell ionization cross sections were measured for Ti, Co, Ge, Rb, and Sn for incident oxygen ions from 16-44 MeV. The x-rays were measured with a high resolution Si(Li) detector (166 eV at 5.9 keV). All of the data represents cross section measurements for thin targets. The measured cross sections for these elements are compared to the theoretical predictions of the Binary Encounter Approximation (BEA). Kα/Kβratios and energy shifts were also extracted from the data. The experimental data are compared to measured cross sections for other elements to give an overview of the systematics for oxygen ion induced x-ray production cross sections in this energy range. Some comment will also be given in regard to the use of oxygen ions to measure the parameters associated with ion implanted semiconductors.

LIGHT ION-INDUCED L-SHELL IONIZATION OF HIGH-Z ELEMENTS

1996 ◽  
Vol 06 (01n02) ◽  
pp. 39-50 ◽  
Author(s):  
E. PERILLO ◽  
P. CUZZOCREA ◽  
N. DE CESARE ◽  
G. SPADACCINI ◽  
M. VIGILANTE
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
Wave Functions ◽  
Ionization Cross ◽  
X Ray ◽  
Li Ion ◽  
Ion Impact ◽  
Ionization Cross Sections ◽  
Coupled Channel ◽  
Shell Ionization

L-shell X-ray production cross sections for selected heavy elements (Tl, Pb, Bi), of interest in BIO-PIXE analyses, have been measured by proton and 7 Li ion impact in the energy range 0.8–2.6 MeV and 1.8–3.3 MeV respectively. Further, production cross sections for 7 Li ion impact on Au between 1.0 and 2.4 MeV have been measured. L-subshell ionization cross sections have been extracted and arranged, together with similar results from other laboratories, in an analysis aiming at testing the performance of various theoretical approximations in the description of the ionization process. The disagreement observed at low values of the reduced velocity parameter ξ R L between the data and the predictions of the ECPSSR model is significantly reduced by using a United Atom approximation in the treatment of the binding correction, suggested by our group (ECPSSR-UA). The remaining discrepancies, mostly for the L 1-subshell, are almost completely removed by replacing the screened hydrogenlike wave functions with the more realistic Dirac-Hartree-Slater ones. In the case of 7 Li ions, especially for L 2-subshell, also a more refined Coulomb deflection correction and more sophisticated coupled channel calculations are needed.

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