Three dimensional (Z-dependence), collective and individual semi-empirical formulae for L X-ray production and ionization cross section by protons impact within corrected ECPSSR theory and updated experimental data: a review

2016 ◽  
Vol 45 (5) ◽  
pp. 247-257
Author(s):  
B. Deghfel ◽  
A. Kahoul ◽  
I. Derradj ◽  
A. Bendjedi ◽  
F. Khalfallah ◽  
...  
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Ionization Cross Section ◽  
Three Dimensional ◽  
Ionization Cross ◽  
X Ray ◽  
Ecpssr Theory ◽  
Semi Empirical

A measurement of the ionization cross-section of Ne + to Ne 2+ by electron impact

1963 ◽  
Vol 274 (1359) ◽  
pp. 546-551 ◽  
Keyword(s):  
Electron Energy ◽  
Cross Section ◽  
Ionization Cross Section ◽  
Incident Electron Energy ◽  
Ionization Cross ◽  
Maximum Value ◽  
Beam Method ◽  
The Cross ◽  
Semi Empirical ◽  
Limits Of Error

The crossed-beam method described by the authors in 1961 was used to measure the cross-section of Ne + in the reaction Ne + + e → Ne 2+ + 2 e . The cross-section increases linearly with electron energy near the threshold and attains a maximum value of 3·13 x 10 -17 cm 2 at 200 eV. The errors in the measurements were estimated to be less than ± 10% and the highest incident electron energy used was 1000 eV. A semi-empirical formula proposed by Drawin in 1961 describes the measured cross-section within the above limits of error when the two adjustable parameters take the values ξf 1 = 5·25 and f 2 = 0·70.

High Precision Multiple Kev X-Ray Analysis: Tests of Ionization Cross Sections and Monte Carlo Algorithms

1997 ◽  
Vol 3 (S2) ◽  
pp. 887-888
Author(s):  
John T. Armstrong ◽  
D. E. Newbury ◽  
P. K. Carpenter
Keyword(s):  
Monte Carlo ◽  
Electron Beam ◽  
Cross Section ◽  
High Precision ◽  
Atomic Number ◽  
Ionization Cross Section ◽  
Production Rates ◽  
Ionization Cross ◽  
X Ray ◽  
Monte Carlo Algorithms

Determination of the variation of absolute and relative electron-excited x-ray production rates as a function of electron beam energy and sample atomic number is necessary for calculation of the "stopping power" atomic number correction and the relative amount of characteristic fluorescence and for development of “standardless” and Monte Carlo algorithms for quantitative x-ray analysis. Critical to the calculation of x-ray production rates is an accurate expression for the inner shell electron ionization cross section. A large number of expressions have been proposed for the relative x-ray production rates (used in the fluorescence correction)1 and for the ionization cross section used in the atomic number correction, and these yield quite different results. In order to evaluate which expressions gave the most accurate results when applied to quantitative x-ray emission measurements, we performed a series of high precision measurements of x-ray intensities as a function of electron beam accelerating potential for a series of pure element and simple oxide, phosphide, sulfide, and chloride standards for 65 elements ranging in Z from C to U

Measurement of X-ray Emission Efficiency for K-lines

2004 ◽  
Vol 10 (4) ◽  
pp. 481-490 ◽  
Author(s):  
M. Procop
Keyword(s):  
Cross Section ◽  
Ionization Cross Section ◽  
Detection Efficiency ◽  
Ionization Cross ◽  
X Ray ◽  
Uncertainty In Measurement ◽  
Emission Efficiency ◽  
Low Emission ◽  
Takeoff Angle ◽  
First Time

Results for the X-ray emission efficiency (counts per C per sr) of K-lines for selected elements (C, Al, Si, Ti, Cu, Ge) and for the first time also for compounds and alloys (SiC, GaP, AlCu, TiAlC) are presented. An energy dispersive X-ray spectrometer (EDS) of known detection efficiency (counts per photon) has been used to record the spectra at a takeoff angle of 25° determined by the geometry of the secondary electron microscope's specimen chamber. Overall uncertainty in measurement could be reduced to 5 to 10% in dependence on the line intensity and energy. Measured emission efficiencies have been compared with calculated efficiencies based on models applied in standardless analysis. The widespread XPP and PROZA models give somewhat too low emission efficiencies. The best agreement between measured and calculated efficiencies could be achieved by replacing in the modular PROZA96 model the original expression for the ionization cross section by the formula given by Casnati et al. (1982) A discrepancy remains for carbon, probably due to the high overvoltage ratio.

PIXE MICROANALYSIS OF VERY LOW Z ELEMENTS BY SUB MeV PROTON BEAM

1993 ◽  
Vol 03 (02) ◽  
pp. 109-120 ◽  
Author(s):  
USAMA M. EL-GHAWI
Keyword(s):  
Experimental Data ◽  
Proton Beam ◽  
Cross Section ◽  
Ionization Cross Section ◽  
Theoretical Calculations ◽  
X Rays ◽  
Ionization Cross ◽  
Ge Detector ◽  
Minimum Detection Limits ◽  
Modified Theory

Analysis of very low Z elements between Be and Si using sub MeV proton beam is explored based on theoretical calculations and supported by experimental data. With the availability of the new LE Ge detector, Be K α X-rays can be recorded with reasonable efficiency and high resolution. PWBA and the modified theory, ECPSSR, have been used for ionization cross-section calculation. Minimum detection limits (MDL’s) for thin target conditions are presented in the energy range of 150–2500 keV.

Ionization Cross Sections for Quantitative Electron Probe Microanalysis

2001 ◽  
Vol 7 (S2) ◽  
pp. 672-673
Author(s):  
C. Merlet ◽  
X. Llovet ◽  
S. Segui ◽  
J.M. Fernández-Varea ◽  
F. Salvat
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Ionization Cross Section ◽  
Ionization Cross ◽  
Quantitative Electron Probe Microanalysis ◽  
Ionization Cross Sections ◽  
Semi Empirical ◽  
Quantitative Epma

Quantitative procedures in electron probe microanalysis (EPMA) require the knowledge of various atomic parameters, the most fundamental of which is the ionization cross section. A number of semi-empirical, approximate analytical formulas have been proposed to calculate the ionization cross section. The simplicity of these formulas makes them suitable for quantitative EPMA procedures. However, it is difficult to assess their reliability because of the lack of accurate experimental data. Indeed, inspection of currently available data reveals that they are still scarce for many elements and, when they are available, one usually finds significant discrepancies between data from different authors. Fortunately, the inaccuracies in the semi-empirical cross section formulas used in EPMA have only a small effect on the analytical results when standards are used. Nonetheless, in quantitative EPMA studies at low overvoltages or using standardless methods, the evaluated compositions largely depend on the adopted ionization cross sections and, therefore, knowledge of accurate ionization cross sections is a requisite for the development of improved quantification methods.

scholarly journals Fundamental Parameters Related to Selenium Kα and Kβ Emission X-ray Spectra

Atoms ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 8
Author(s):  
Mauro Guerra ◽  
Jorge M. Sampaio ◽  
Gonçalo R. Vília ◽  
César A. Godinho ◽  
Daniel Pinheiro ◽  
...  
Keyword(s):  
Cross Section ◽  
Intensity Ratio ◽  
Ionization Cross Section ◽  
Theoretical Calculations ◽  
Usual Method ◽  
Ionization Cross ◽  
X Ray ◽  
Fundamental Parameters ◽  
Initial States ◽  
Experimental Values

We present relativistic ab initio calculations of fundamental parameters for atomic selenium, based on the Multiconfiguration Dirac-Fock method. In detail, fluorescence yields and subshell linewidths, both of K shell, as well as Kβ to Kα intensity ratio are provided, showing overall agreement with previous theoretical calculations and experimental values. Relative intensities were evaluated assuming the same ionization cross-section for the K-shell hole states, leading to a statistical distribution of these initial states. A method for estimating theoretical linewidths of X-ray lines, where the lines are composed by a multiplet of fine-structure levels that are spread in energy, is proposed. This method provides results that are closer to Kα1,2 experimental width values than the usual method, although slightly higher discrepancies occur for the Kβ1,3 lines. This indicates some inaccuracies in the calculation of Auger rates that have a higher contribution for partial linewidths of the subshells involved in the Kβ1,3 profile. Apart from this, the calculated value of Kβ to Kα intensity ratio, which is less sensitive to Auger rates issues, is in excellent agreement with recommended values.

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