An Experimental Evaluation of the Atomic Number Effect

1973 ◽  
Vol 17 ◽  
pp. 479-486
Author(s):  
L. Parobek ◽  
J. D. Brown
Keyword(s):  
Experimental Data ◽  
Electron Beam ◽  
Atomic Number ◽  
Alloy System ◽  
Sample Surface ◽  
Pure Element ◽  
X Ray ◽  
Low Concentrations ◽  
Sample Technique ◽  
Intensity Ratios

AbstractA method for measuring the atomic number effect is developed using a sandwich sample technique. The depth distributions of x-ray production, ϕ(ρz) curves, have been measured for a zinc tracer in aluminum, copper, silver and gold matrices at 30, 25, 20 and 15 keV. The ϕ(ρz) curves were measured using a Cambridge Microscan 5 in which the electron beam is normal to the sample surface and the x-ray take-off angle is 75°.Samples of the low concentrations of copper (∼1 Weight %) in aluminum, nickel, silver and gold were prepared. For each alloy system (for example, Cu - Al), three different concentrations of copper were prepared. The intensity ratios from the sample to the pure element (standard) for each system have been plotted against concentration. At such low concentrations of copper the relation between this ratio and concentration is linear. The slopes of the curves have been compared to the equivalent factors obtained as ratios of the area under F(ρz) curves for aluminum, silver and gold to the area under F(ρz) curve for copper, respectively. The F(ρz) curves are obtained from ϕ(ρz) curves; F(ρz) = ϕ(ρz) exp(-μρz csc ψ) where μ is mass absorption coefficient.Comparisons are made between these experimental data and the current methods of calculating the atomic number effect.

Some Observations on X-Ray Emission as a Function of Accelerating Voltage in the Microprobe

1964 ◽  
Vol 8 ◽  
pp. 384-399
Author(s):  
D. L. Burk
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Atomic Number ◽  
X Ray ◽  
Absorption Wavelength

AbstractData are presented from several systems for which the emitted X-ray intensity goes through a maximum as accelerating voltage is increased. An attempt is made to systematize the data in terms of absorption, wavelength, and atomic number. A very simple model, analyzed graphically, is capable of displaying many of the features of the experimental data.

X-Ray Fluorescence Spectrometric Determination of Rare Earths in Plutonium

1968 ◽  
Vol 22 (5) ◽  
pp. 434-437 ◽  
Author(s):  
E. A. Hakkila ◽  
R. G. Hurley ◽  
G. R. Waterbury
Keyword(s):  
Rare Earths ◽  
Internal Standard ◽  
Internal Standard Method ◽  
X Rays ◽  
Measured Intensity ◽  
X Ray ◽  
Low Concentrations ◽  
Relative Standard ◽  
Intensity Ratios

Two methods were evaluated for determining rare earths in plutonium: (1) For the lighter rare earths ( Z≦66), or low concentrations of the heavier rare earths, an adjacent rare earth was added as a carrier and also as an internal standard, the rare earths were separated from plutonium by fluoride precipitation, and the measured intensity ratios for the sample and for solutions having known concentrations were compared. The Lβ1 x-rays were measured for the lighter rare earths and the Lα1 x rays for the remaining lanthanides. (2) For the heavier rare earths ( Z>66), the Lα1 x-ray intensities were measured from a nitric acid solution of the sample and compared to intensities obtained for solutions having known concentrations. The minimum concentrations that could be measured with a relative standard deviation no greater than 4% by the separation internal standard method varied from approximately 0.5% for lanthanum to 0.01% for lutetium. The direct measurement of x-ray intensity was much less sensitive. Applicability of the methods was shown by successful analyses of plutonium alloys containing dysprosium, thulium, or lutetium.

Quantification of losses during X-ray microanalysis of mercury

1978 ◽  
Vol 36 (2) ◽  
pp. 12-13
Author(s):  
T. Bistricki
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Mass Loss ◽  
Atomic Number ◽  
High Vacuum ◽  
Analytical Electron Microscopy ◽  
X Ray ◽  
Low Level ◽  
Analytical Electron ◽  
Concentration Levels

Diminution of the X-ray signal from the elements of low atomic number and mass loss associated with electron excited X-ray microanalysis have been demonstrated elsewhere. The elements of higher atomic number did not receive sufficient attention although under severe conditions of analytical electron microscopy, the losses of any of the specimen's elemental components exposed to the electron beam bombardment in high vacuum are to be expected and have been indicated previously. Unlike the elements of low atomic number, the losses of heavier elements, like mercury, are usually not detected unless a mass of the element within the excited volume is at a very low level (10-11 g range or less) or analytical conditions are extremely unfavourable, in which case considerable losses may occur even when concentration levels are by orders of magnitude higher (10-9 g range or higher).

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

Peak Broadening in Asymmetric Powder Diffraction

1992 ◽  
Vol 36 ◽  
pp. 603-607
Author(s):  
Danut Dragoi
Keyword(s):  
Experimental Data ◽  
Composite Material ◽  
Powder Diffraction ◽  
Ceramic Composite ◽  
Sample Surface ◽  
Divergence Angle ◽  
Bragg Angle ◽  
X Ray ◽  
Peak Broadening ◽  
Constant Distribution

AbstractIn the case of asymmetric X-Ray powder diffraction, usually used for stress analysis, the peak broadening is a function of the following instrumental parameters: divergence angle of incident and diffracted X-Ray beams (equatorial divergence), divergence angle of Soller slits (axial divergence), tilt angle ψ, and the intrinsic parameters of the sample (Bragg angle, size and mosaicity of the microcrystals, crystallographic imperfections due to atom impurities). This effect of peak broadening is discussed quantitatively, independent of the form of the peak, by using an approximation of a constant distribution of the intensities of diffracted X-Ray beams. The broadening effect due only to the ψ tilt of the sample surface is studied in this work. The results are compared with experimental data obtained on ceramic composite material: α-Al2O3/SiC(whisker).

scholarly journals The Influence of Nitrogen Absorption on Microstructure, Properties and Cytotoxicity Assessment of 316L Stainless Steel Alloy Reinforced with Boron and Niobium

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 506 ◽  
Author(s):  
Sadaqat Ali ◽  
Ahmad Majdi Abdul Rani ◽  
Riaz Ahmad Mufti ◽  
Farooq I. Azam ◽  
Sri Hastuty ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Photoelectron Spectroscopy ◽  
316L Stainless Steel ◽  
Artificial Saliva ◽  
Alloy System ◽  
Sample Surface ◽  
Nickel Ions ◽  
X Ray ◽  
Cytotoxicity Assessment

In the past, 316L stainless steel (SS) has been the material of choice for implant manufacturing. However, the leaching of nickel ions from the SS matrix limits its usefulness as an implant material. In this study, an efficient approach for controlling the leaching of ions and improving its properties is presented. The composition of SS was modified with the addition of boron and niobium, which was followed by sintering in nitrogen atmosphere for 8 h. The X-ray diffraction (XRD) results showed the formation of strong nitrides, indicating the diffusion of nitrogen into the SS matrix. The X-ray photoelectron spectroscopy (XPS) analysis revealed that a nitride layer was deposited on the sample surface, thereby helping to control the leaching of metal ions. The corrosion resistance of the alloy systems in artificial saliva solution indicated minimal weight loss, indicating improved corrosion resistance. The cytotoxicity assessment of the alloy system showed that the developed modified stainless steel alloys are compatible with living cells and can be used as implant materials.

Epitaxial Growth of Ni on Si by Ion Beam Assisted Deposition

1988 ◽  
Vol 128 ◽  
Author(s):  
K. S. Grabowski ◽  
R. A. Kant ◽  
S. B. Qadr
Keyword(s):  
Electron Beam ◽  
Epitaxial Growth ◽  
Crystallographic Texture ◽  
Room Temperature ◽  
Ion Beam ◽  
Sample Surface ◽  
Electron Beam Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Beam Assisted Deposition

ABSTRACTEpitaxial Ni films were grown on Si(111) substrates to a thickness of about 500 nm by ion beam assisted deposition at room temperature. The films were grown using 25-keV-Ni ions and electron-beam evaporation of Ni at a relative arrival ratio of one ion for every 100 Ni vapor atoms. The ion beam and evaporant flux were both incident at 45° to the sample surface. Standard θ-2θ X-ray diffraction scans revealed the extent of crystallographic texture, while Ni {220} pole figure measurements identified the azimuthal orientation of Ni in the plane of the film. Films grown without the ion beam consisted of nearly randomly oriented fine grains of Ni whereas with bombardment the Ni (111) plane was found parallel to the Si (111) plane. In all the epitaxial cases the Ni [110] direction was perpendicular to the axis of the ion beam, suggesting that the azimuthal orientation of the film was determined by channeling of the ion beam down {110} planar channels in the Ni film. Additional experiments with different ions, energies, and substrates revealed their influence on the degree of epitaxy obtained.

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