bluuebunny/crossref_metadata_2025 huggingface dataset:
Relative intensity factors for K, L and M shell x‐ray lines
Authors: Schreiber T. P. , Wims A. M.
Published: May 2005

Accurate values for x‐ray relative intensity factors, which are the fraction of intensity measured, are important for quantitative calculation procedures used in scanning transmission electron microscope thin film x‐ray microanalysis. We have developed equations for calculating these parameters for the K, L and M shells and have applied them to a thin film quantitative analysis procedure. The K shell values were obtained from experimental and theoretical data in the literature and show a constant region between atomic numbers 20 and 30. To obtain L shell values measurements were made with an electron probe and an energy dispersive system on a 200 kV scanning transmission electron microscope. These data were combined with values calculated from Coster‐Kronig and fluorescence yield data in the literature. The result was two curves with a step at atom number 51 and a significantly different magnitude than values used in other thin film methods. The following equations for use in a computer program were developed from these curves; aLα1.2(Z=27−50)=1.617−0.0398Z+3.766 × 10−4Z2; aLα1,2(Z=51−92)=0.609−1.619 × 10−3Z−0.03248 sin [0.161(Z−51)].
Comparison of the intensity correction method and the analytical value correction method in the correction of interfering spectrum overlap
Authors: Ito Minao , Sato Shoki , Narita Masanao
Published: May 2005

In the X‐ray fluorescence analysis of steels, a correction method is usually used so as to eliminate interfering spectrum overlap and absorption–enhancement effects. In correcting the former, the intensity correction method, by which measured x‐ray intensity is corrected, is widely used. In the JIS method of x‐ray fluorescence analysis of steels, however, the measured x‐ray intensity is first converted into a tentative analytical value, and this value is then corrected for absorption–enhancement effects and finally for interfering spectrum overlap. In this report, a detailed comparison of both methods is made, and the characteristics of the JIS method are discussed.
X‐ray fluorescence analysis of silver and palladium film thicknesses on silicon solar cells
Authors: Artz B. E. , Bomback J. L.
Published: May 2005

An x‐ray fluorescence technique was developed to analyze the thickness of Ag and Pd metallization layers on the back side contacts of Si solar cells. The technique employed a Sn secondary target x‐ray source excited by a Cr target x‐ray tube. Sn Kβ excited Ag Kα in the overlying Ag contact while Sn Kα and Kβ excited Pd Kα in the underlying Pd film. The emitted Ag and Pd Kα intensities were compared with corresponding intensities emitted from pure bulk Ag and Pd standards. Attenuation of Sn Kβ and Sn, Ag and Pd Kα in the Ag contact and in the standards was accounted for in the calculations. The results on 17 cells compared favorably with neutron activation analyses. An accuracy of ±10% was estimated for a 40 nm Pd film beneath a 7 μm Ag contact. Palladium films as thin as 1.5 nm were analyzed. The technique is nondestructive and can be applied to process control in a production environment as well as to laboratory testing of experimental cells.
Influence of interelement effects on x‐ray fluorescence calibration curve coefficients for binary mixtures
Authors: Mainardi R. T. , Fernández J. E. , Nores M.
Published: May 2005

It has been shown that x‐ray fluorescence calibration curve coefficients are closely related to matrix effects, such as absorption or absorption plus enhancement of the fluorescent radiation. In the classical paper of Rasberry and Heinrich,1 a single coefficient (named Aik) calibration curve was proposed when pure absorption is the predominant effect on the spectral line of interest. Similarly, and for practical purposes, a single coefficient (named Bik) was also considered when absorption and enhancement are present. We propose a new interpretation of calibration curve coefficients based on analytical expressions obtained recently for binary compounds under monochromatic excitation. Six distinct possible cases of calibration curves arise. Examples of binary compounds for each case are given. The data considered have been computed using the fundamental parameters method which allowed us to study a large number of possible mixtures for an arbitrary monochromatic excitation. Finally, through a different approach we discuss how this analysis could be extended to consider polychromatic excitation.
Automated qualitative wavelength‐dispersive x‐ray fluorescence analysis
Authors: Platbrood G. , Serbruyns M. , Quitin J. M.
Published: May 2005

A SRSO1 Siemens x‐ray spectrometer equipped with a logical controller was controlled by a Tektronix 4051 computer to record step by step the x‐ray fluorescence intensities. Ten samples can be analysed after the recording of 2 spectra (LiF (110) and PET) for each sample on a magnetic tape. On a host computer, a program first reduces the x‐ray fluorescence spectra to find the peak parameters for each line and another program subsequently identifies the elements.
The concentration correction equations as a consequence of the shiraiwa and fujino equation
Authors: Kuczumow A.
Published: May 2005

Certain concentration correction equations are considered as a consequence of the Shiraiwa and Fujino equation. Particular correction equations are related to special physical cases. A set of differential equations, derived on the ground of Claisse's considerations, co‐exist with the set of classic correction equations. The mutual relations between the classic correction equations are presented.
Correction method for the particle‐size effect in the x‐ray fluorescence analysis of ‘Thin’ and monolayer samples
Authors: Hołyńska Barbara , Markowicz Andrzej
Published: May 2005

A method of correction for the particle‐size effect in the x‐ray fluorescence analysis of thin and monolayer samples is proposed. The method consists of the measurement of characteristic x‐rays excited by x or γ radiation of two different energies. A concept of a substitute radiometric particle diameter instead of the particle‐size distribution has been introduced in order introduced in order to enable a practical application of the proposed method. The particle‐size correction factors have been obtained theoretically and experimentally for iron oxide (Fe3O4), calcium sulphate (CaSO4) and copper sulphide (Cu2S) with various particle‐size distributions. The application limits of the proposed method have been discussed.
Graphical comparison of mathematical models for quantitative x‐ray fluorescence analysis
Authors: Platbrood G. , Simon S.
Published: May 2005

Several mathematical models for correcting x‐ray fluorescence intensities are proposed in the literature. However, it is not always easy for the analyst to choose the best one for a particular case. Therefore a modular program has been written to compare automatically mathematical models for quantitative x‐ray spectrometry with the object of determining the best conditions of analysis (models, number and nature of interfering elements and matrix effects). The graphic display of the standard deviation of the standards as a function of the interfering elements used in the correction simplifies and accelerates the interpretation of the matrix effects.
Rapid determination of ash in coke using Compton scattering
Authors: Pandey H. D. , Shastry C. R.
Published: May 2005

The Compton scattering technique for rapid determination of ash content in coal has been extended to coke samples. Some improvements in respect of the sample preparation and possible line overlap and background have been incorporated. A modified regression equation used in this work to compute the x‐ray data is found to yield good results.
L11 and L111 x‐ray absorption discontinuities of Tb in some Tb compounds
Authors: Kumar A. , Salem S. I.
Published: May 2005

The L11 and L111 absorption discontinuities of Tb in various Tb compounds have been recorded using an automated and highly stable x‐ray unit. The energy shifts have been discussed in terms of effective ionic charge. Applying Levy's method, the radii of the first coordination sphere have been calculated from the extended fine structure.
Intercomparison of selected semi‐empirical and fundamental parameter interelement correction methods in x‐ray spectrometry
Authors: Pella P. A. , Sieber J. R.
Published: May 2005

Fundamental parameter interelement correction methods such as NRLXF are finding increased use in quantitative x‐ray spectrometry. The purpose of this work was to compare the results obtained with each of the three options in NRLXRF, namely empirical, full, and theoretical, with a semiempirical model such as Rasberry‐Heinrich and an NBS fundamental parameter method to check for consistency. Well characterized alloys were chosen for making the intercomparison.
An overview of EXFNBS—A data reduction procedure for energy‐dispersive XRF with secondary target excitation
Authors: Myklebust R. L. , Pella P. A. , Thorne B.
Published: May 2005

An overview of a fundamental parameter, data reduction procedure for processing energy‐dispersive, x‐ray spectrometric data obtained with monochromatic excitation is described. The programs, called EXFNBS and NBSROI, are written in FORTRAN and correct for interfering x‐ray peaks, escape peaks, background, and x‐ray absorption/enhancement due to interelement effects in a speciment. This procedure is designed to operate in an interactive mode with a minicomputer in real time.
The accuracy and precision of routine energy‐dispersive electron microprobe analysis of serpentine
Authors: Wicks F. J. , Plant A. G.
Published: May 2005

A serpentine mineral specimen used for a standard in a Materials Analysis Company Model 400 electron microprobe equipped with a Kevex Model 5000A energy dispersive sperctrometer and an on‐line Hewlett–Packard 2100 computer, was repeatedly analysed during a study of serpentinization. The results of the repeated analyses were statistically analysed and show an acceptable level of accuracy and precision. The relative and absolute errors for the serpentine standard lie within the same ranges as the errors for the other standards (forsterite, enstatite, diopside, kyanite and kaersutite) used, although the standard deviations for the serpentine analyses are slightly greater. These results are within acceptable limits and indicate that serpentine can be routinely analysed by energy dispersed analysis, using a serpentine standard for magnesium and silicon determinations, with the same accuracy but with slightly lower precision than less hydrous silicates. Most elements were present in amounts between 2 to 63 wt% of the oxide in the standards used but 0.31 wt% Al2O3 present in the serpentine standard was routinely determined with acceptable results.
XRF analysis of trace titanium in coal using fundamental parameters
Authors: Garbauskas M. F. , Wong J.
Published: May 2005

The analysis of various elements in coal has become important as coal utilization increases. The application of x‐ray fluorescence (XRF) to this type of analysis is complicated by matrix‐correction needs and lack of matrix‐matched standards. The application of fundamental parameter mathematical corrections using easily obtainable doped graphite standards is evaluated.
Evaluation of a correction method for the particle‐size effect in x‐ray fluorescence analysis of ‘Thin’ and monolayer samples
Authors: Markowicz Andrzej
Published: May 2005

The application limits of a correction method for the particle‐size effect in x‐ray fluorescence (XRF) analysis are estimated theoretically in the presented paper. This correction method requires the use of two sources of exciting γ‐or x‐radiation of different energies.1 The influence of the different values of the parameter t′ (which is a function of the linear absorption coefficients for primary and fluorescent radiation) and the influence of the relative standard deviation, Sr (resulting from counting statistics) have been taken into account in evaluating the efficiency of the method. In addition, the criteria for the selection of the optimum energies of the exciting radiation, the proper times of measurement and the activities of the sources of primary radiation are proposed. An example of the application of the proposed criteria to the determination of iron (as Fe3O4) is presented.
X‐ray production in thin films by electrons with energies between 40 and 100 keV. 2—Characteristic cross‐sections and the overall x‐ray spectrum
Authors: Gray C. C. , Chapman J. N. , Nicholson W. A. P. , Robertson B. W. , Ferrier R. P.
Published: May 2005

Two approximate theories are considered for the production of characteristic x‐rays when thin foil targets are bombarded with electrons with energies between 40 and 100 keV. One, due to Kolbenstvedt, is semi‐classical in nature whilst the other, due to Bethe, contains two parameters which are normally adjusted empirically. Data from six different target materials are presented, but because errors in experimentally derived absolute cross‐sections are large, a comparison is made between theoretical and observed ratios of characteristic Kα photons to bremsstrahlung photons in a 20 eV channel directly beneath the peak. By adjusting the Bethe parameters and using a modified Bethe‐Heitler theory to predict the bremsstrahlung, agreement between experiment and theory of typically 10% is recorded. Finally, a means of simplifying the equations used to enable rapid calculation of x‐ray spectra with a pocket calculator is indicated.
Energy‐dispersive x‐ray fluorescence analysis of silicate rocks for major and trace elements
Authors: Potts P. J. , Webb P. C. , Watson J. S.
Published: May 2005

The performance of an energy‐dispersive x‐ray fluorescence (ED‐XRF) system for the analysis of silicate rocks was investigated in detail. Data are presented to demonstrate the selection of optimum excitation conditions for the major elements (Na‐Fe), analysed on glass beads, and the trace elements (particularly the Rb‐Nb group) analysed on powder pellets. Limitations in spectrum analysis due to overlap interferences are discussed and have largely been overcome using x‐ray profile fitting software. The results show that when operated under optimum excitation conditions, ED‐XRF spectrometry can routinely achieve a high degree of accuracy and precision in the analysis of a wide range of major and trace elements in silicate rocks. For many elements, 2s standard deviations are better than 2% relative. Limits of determination for many trace elements are in the range 4–10 ppm.
Heterogeneity effects in direct x‐ray fluorescence analysis of hair
Authors: Török Sz. , Van Dyck P. , Van Grieken R.
Published: May 2005

The methodology of direct hair analysis by energy‐dispersive x‐ray fluorescence was studied. The effect on the XRF result of having a non‐homogeneous radial distribution of the analyte in a single hair strand and the macroscopic effects in a bundle of hairs were calculated to evaluate possible systematic errors. The detection limits were mapped as a function of the target thickness and surface fraction. It appeared that a 10 mg cm−2 sample thickness, i. e. a target with about four layers of hair strands, is recommended. The standard deviation of this simple direct analytical method is 6–19% for some important elements. Discrepancies with neutron activation analysis had a mean value of around 15%. About twelve elements can be determined simultaneously on a routine basis.
Reflective properties of beryl and gypsum crystals in the 1 keV photon energy region
Authors: Belin E. , Zuckerman S. , Sénémaud C.
Published: May 2005

Reflexion Curves from gypsum and beryl crystals have been calculated using the dynamic theory of x‐ray diffraction, assuming that the crystal is perfect, and taking into account the photoabsorption of incident photons by the crystal. The calculations were performed for two values of photon energy: 851 eV (Ni Lα emission) and 1098 eV (Ga Lα emission). The results are discussed comparatively.
A modification of Kramers' law for the x‐ray continuum from thick targets
Authors: Brunetto M. G. , Riveros J. A.
Published: May 2005

The intensity of an x‐ray continuum had been generated theoretically for incident electron energies between 10 and 45 keV, radiated photon energies between 2 and 40 keV and over the whole range of atomic numbers (from Z = 1 to 100). For these cases a relatively simple expression was found which shows the dependence of continuous radiation on the atomic number, incident electron energy and radiated energy. In order to compare observed intensities with this expression, we have made corrections for self‐absorption in the target, for loss of ionization due to backscatter and for absorption by the exit window of an x‐ray tube. Our expression provides a better description of experimental observations than dose Kramers' equation.
Radiative Auger transitions and their consideration in deconvolution of energy dispersive x‐ray spectra
Authors: Marageter E. , Wegscheider W. , Müller K.
Published: May 2005

The significance of Auger transitions as spectral components in energy dispersive x‐ray fluorescence spectra is demonstrated. As a summary of fundamental studies on radiative Auger effects the calculation of their energies and relative intensities is demonstrated. These theoretical deductions result in a suitable incorporation in least‐squares techniques by coupling the Auger transitions to the corresponding photopeak originating from the same type of primary vacancy as a function of energy. The simplifications involved, and the removal of systematic misinterpretations and of high correlations of model parameters, are discussed.
Evaluation of the use of Gaussian ϕ(ρz) curves in quantitative electron probe microanalysis: A new optimization
Authors: Bastin G. F. , Van Loo F. J. J. , Heijligers H. J. M.
Published: May 2005

A computer program based on the use of Gaussian expressions for the x‐ray distribution with depth [ϕ(ρz)curves] was tested on its usefulness for quantitative electron probe microanalysis. As the good results originally claimed for a similar program could not be reproduced initially, it was subjected to a detailed analysis. As a result, some modifications in the approach are proposed. Apart from increasing the speed of calculation considerably, the modified expressions provide a better insight into the delicate balance which has to exit between the relevant quantities involved. After a new optimization process the modified program was tested on about 450 published microanalyses. The results show that the ϕ(ρz) approach is indeed very promising as a narrow histogram with an r. m. s. value of 5. 4% could be produced. Finally, some suggestions are made for future improvements.
Fundamental algorithm between concentration and intensity in XRF analysis 2—practical application
Authors: Rousseau Richard M.
Published: May 2005

In Part 1, a new formalism was proposed to correct with accuracy the matrix effects in XRF analysis. In this paper it is shown how to adapt this new formalism to practical situations. From an estimate of composition calculated by the Claisse–Quintin algorithm and an appropriate calibration, the new algorithm is used to refine the estimated composition for greater accuracy. This last approach is equivalent to the ‘fundamental parameters’ method but is presented in a simpler version adaptable to any mini‐computer.
Concentration mapping—a software package for the quantitative determination of two‐dimensional elemental distribution by an electron probe microanalyser
Authors: Mayr M. , Angeli J.
Published: May 2005

Developments starting from known digital mapping techniques led to a powerful and versatile software package, Concentration Mapping (CM), the advantages of which over former programs are as follows: up to 18 elements can be measured; correction calculations can be applied to obtain quantitative results; additional information may be obtained by further data processing; several programs for special data readout, phase analysis and statistical calculations are available; a very efficient automation system makes extended investigations practicable in an economical manner. Some examples of applications are given to demonstrate the extensive information from CM investigations which could not be achieved easily with customary electron probe microanalysis systems.
An analytical algorithm for calculation of spectral distributions of x‐ray tubes for quantitative x‐ray fluorescence analysis
Authors: Pella P. A. , Feng Liangyuan , Small J. A.
Published: May 2005

Fundamental parameter methods for quantitative x‐ray fluorescence analysis require a knowledge of the spectral distributions of x‐ray tubes used for sample excitation. The theoretical models for the calculation of the spectral distributions include a number of parameters which are not known with sufficient accuracy. Also, spectral distributions have been measured for only a few x‐ray tubes operated at 45–50 kV. We have developed an algorithm for calculating x‐ray tube spectral distributions by utilizing extensive electron microprobe data obtained under various operating conditions with a Si(Li) detector. The algorithm includes the calculation of the continuum and the ratio of the characteristic line(s) to the underlying continuum intensity at the wavelength of the characteristic line(s).
A general characteristic fluorescence correction for the quantitative electron microbeam analysis of thick specimens, thin films and particles
Authors: Armstrong John T. , Buseck Peter R.
Published: May 2005

A rigorous, general characteristic fluorescence correction for the electron microprobe analysis of samples of given geometry is developed, and specific versions of this equation are presented for the calculation of the fluorescence produced (a) within a homogeneous thin film, (b) in a thin film by x‐ray emission from substrate layers of arbitrary thickness and (c) in a spherical particle. Results of the use of these equations are compared with those obtained using empirical expressions for thin films and show that the empirical expressions are accurate only for films less than 1 μm in thickness. A simplified empirical correction is proposed for particles that is in good agreement with the rigorous correction. The results of calculations using these expressions show that a 2000 Å thick film or a 1 μm diameter particle typically has about 10% of the relative contribution from characteristic fluorescence as occurs in an infinitely thick polished specimen (TPS), a 1 μm thick film has about 30–40% of the contribution in a TPS and a 10 μm diameter particle has more than 50% of the contribution in a TPS. Thus, in particular matrices, certain elements in a 2000 Å thin film or a 1 μm particle can have characteristic fluorescence corrections as high as 5%.
Determination of the valence of the iron in welding fumes with the Kβ emission spectrum
Authors: Tanninen V.‐P. , Mikkola E. , Hyvärinen H.‐K. , Grekula A. , Kalliomäki P.‐L.
Published: May 2005

The average valence of the iron present in the most common types of welding fumes was studied using Fe Kβ emission lines and a flat crystal spectrometer. Analysis of the energy separation Kβ1,3 – Kβ′ and the intensity ratio of the Kβ′ to Kβ1,3 yielded estimates of the predominant valence state of iron in its oxidic compounds. The presence of pure iron in the four different welding fumes is also discussed on the basis of the x‐ray emission analysis.
Measurement of L and M shell x‐ray production cross‐sections by 6 keV photon
Authors: Shatendra K. , Singh N. , Mittal R. , Allawadhi K. L. , Sood B. S.
Published: May 2005

The cross‐sections for the production of L and M shell x‐rays in some elements by 5.959 keV photons have been measured in order to provide data for use in photon‐induced x‐ray fluorescence analysis. An attempt has been made to interpret the experimental data in terms of the theoretical sub‐shell photoionization cross‐sections, fluorescence and Coster–Kronig yields wherever available. In general, an agreement between the experimental and calculated values was found for the L shell. However, for the M shell, sufficient data for comparison were not available.
Quantitative electron probe microanalysis of carbon in binary carbides. II—data reduction and comparison of programs
Authors: Bastin G. F. , Heijligers H. J. M.
Published: May 2005

The performances of four current matrix correction programs have been tested on a data file of measurements on 13 binary carbides between 4 and 30 kV. Both the metal lines as well as the carbon Kα line have been measured, which resulted in 145 k ratios for the metals (relative to elemental standards) and 117 integral k ratios for carbon Kα (relative to Fe3C).

Evidence is presented that the existing sets of mass absorption coefficients for carbon Kα radiation are perhaps not fully consistent and a new set is therefore proposed, which is in better agreement with the experimental results. Finally, it is shown that the modified Gaussian ϕ(ρz) approach, when used in conjunction with the new set of mass absorption coefficients, leads to unexpectedly good results, with a relative root‐mean‐square value of 3.7%. This demonstrates that even for carbon very good accuracy can be obtained, provided that proper care is exercised in the measurements and the proper procedures are followed.
Quantitative analysis of binary mixtures using a simple x‐ray fluorescence technique
Authors: Mittal Raj , Allawadhi K. L. , Sood B. S.
Published: May 2005

A method is described for the quantitative analysis of binary mixtures using a simple x‐ray fluorescence technique. It requires neither special preparation of thin samples nor corrections for absorption and enhancement effects. Enhancement effects are avoided using selective excitation and absorption is estimated in terms of intensities of the measured x‐rays. Linear calibrations requiring the use of only two standards are obtained. The application of the method is illustrated with six different binary mixtures.
Calculation of the influence coefficients for the claisse–quintin algorithm
Authors: Wadleigh Kevin R.
Published: May 2005

Rousseau derived the Claisse—Quintin (C—Q) equation from Sherman's equation. His theoretical description of the influence coefficients used in the C—Q equation is not correct. Also, Rousseau and Claisse as well as Rousseau gave methods for calculating influence coefficients for the C—Q equation but the coefficients listed in their papers are in error. The purpose of this paper is two‐fold: to give a set of equations that contain the correct theoretical description of the influence coefficients, and to give the correct equations for the calculation of these influence coefficients.
A comprehensive alpha coefficient algorithm (a second version)
Authors: Rousseau Richard M.
Published: May 2005

An expression proposed by Lachance is suggested to correct for matrix effects in any system analysed by X‐ray fluorescence. If, for any reason, an analyst does not wish to use the fundamental parameters approach, this expression is a good alternative, yielding accurate results. It is in agreement with the theory and uses influence coefficients calculated from equations containing fundamental parameters only. It is compared with three other expressions correcting for matrix effects and its accuracy is illustrated by calculations for some hypothetical specimens.
Control of chemical composition in tin–lead commercial alloys by wavelength‐dispersive X‐ray spectrometry
Authors: Ward C. Jose
Published: May 2005

Wavelength‐dispersive X‐RAY SPECTROMETRY can be used to great advantage for the rapid monitoring of the composition of tin‐lead solders. However, account must be taken of some metallurgical properties that influence the X‐ray analysis, viz. the development of concentration gradients during solidification and the process of ageing that sets in at room temperature. Only after these problems have been controlled can a reliable analytical procedure be set up. Standards can be prepared with common facilities and matrix effects are dealt with by simple correction models.
LIII EXAFS in holmium
Authors: Agarwal B. K.
Published: May 2005

The holmium LIII extended X‐ray absorption was analysed by the Fourier transform method. The effect of regarding the threshold energy as a parameter is discussed.
Analytic description of Si(Li) spectral lineshapes due to monoenergetic photons
Authors: Campbell J. L. , Perujo A. , Millman B. M.
Published: May 2005

Spectra have been recorded from monochromatized Kα1, Kβ1 and Lα1 X‐rays in the 3—16 keV energy region incident on an Si(Li) detector. An analytic lineshape consisting of a Gaussian plus two Gaussian‐exponential convolutes fits these well, except at very low energy. The intensities and parameters of these tails are explored in the context of the processes responsible, and the behaviour of the shorter tail is compared with the predictions of a model calculation of Auger and photoelectron escape. The well behaved energy dependence of the tailing parameters improves the prospects for more accurate fitting of complex XRF, EPMA and PIXE spectra.
Assessment of the gaussian ϕ(ρz) curves in quantitative electron probe microanalysis without optimization of the parameters
Authors: Saá J. H. Tirira , Del Giorgio M. A. , Riveros J. A.
Published: May 2005

A new expression for the parameter β of the ϕ(ρz) curves is developed and the calculated K intensity ratios are compared with the corresponding experimental K, compiled in previous publications. The results show a mean value for K/K of 1.003, a standard deviation of 4.8% and an asymmetry of 1.01 with respect to unity.
Thick target X‐ray yields from proton bombardment
Authors: Katsanos A. A. , Aravantinos A. , Kallithrakas‐Kontos N.
Published: May 2005

The production yields for characteristic x‐rays from the bombardment of thick targets by protons are calculated by integrating the x‐ray production cross‐section for each element for the whole range of the protons, taking into account the self‐absorption of x‐rays. A simple approximation which can be applied with a pocket calculator is also presented, using simplified relationships for the energy dependence of the proton stopping power and the x‐ray production cross‐sections. The approximation allows very fast calculations, has an accuracy of better than 5% for low‐energy protons and is also very useful for the first steps in a computer program for PIXE analysis of thick targets, using the method of iterations. The calculated yields are compared with experimental results obtained on thick specimens of pure elements, compounds and standards.
Investigations towards optimizing EDS analysis by the Cliff‐Lorimer method in scanning transmission electron microscopy
Authors: Hoeft H. , Schwaab P.
Published: May 2005

The critical specimen thickness up to which the Cliff‐Lorimer method can be used without additional corrections was measured on some steels and nickel‐base alloys for soft x‐rays with line energies between 1 and 3 keV. The critical thickness values measured are 50 nm at 1 keV and 450 to 500 nm at 3 keV. These results indicated that verification of the calibration measurements used for determining the correction factors was necessary in the case of soft radiation. The measurements led to a further optimization of the parameters in the equation used for calculating the ionization cross‐section

The published equations for absorption correction, which becomes necessary when the critical specimen thickness is exceeded, were found to lead to an overcorrection in the case of very thin foils and an insufficient correction in the case of thicker specimens. However, it is only of significance if the specimens are very thick or errors less than 5% are aimed for.
Determination of X‐ray fluorescence sample geometry from compton backscatter energy
Authors: Nielson Kirk K. , Rogers Vern C. , Shuman Rob
Published: May 2005

A method was developed to determine automatically sample positions and correct peak intensities for sample positional variations in x‐ray fluorescence (XRF) analysis. Small shifts in Compton backscatter peak energy are accurately measured in the spectrum and used to compute the mean scatter angle, from which the effective scatter position is determined. New equations were derived to express fluorescent and scatter positions within samples, and to correct peak intensities for geometry variations in a sample of arbitrary thickness, position and composition. The method was validated with an energy‐dispersive XRF system with secondary excitation. With thin samples, the method corrected intensity errors of up to 69% to within 2%, and with samples of intermediate thickness it corrected errors of up to 83% to within 1.7%. The method is important in quantitative fundamental parameter calculations, such as the CEMAS method, which otherwise define the sample to lie in a pre‐determined plane.
Quantitative X‐ray fluorescence analysis of specimens with rough surfaces: Monte Carlo approach
Authors: Ebel H. , Poehn Ch.
Published: May 2005

In general, the application of the fundamental parameter method in quantitative x‐ray fluorescence analysis is restricted to specimens with plane and smooth surfaces. For such surfaces, the correlation of path lengths x of incident tube photons and y of escaping fluorescent photons is well defined. For rough surfaces this correlation is described by distribution functions. Thus, for x1 ≤ x ≤ x2 a probability density Ø(y)x1, x2 allows the probability of y values to be described within the range yA ≤ y ≤ yB. From the results it is now possible to describe probability distributions of rough surfaces by means of Monte Carlo calculations.
Analysis of metallic shred: A basic experiment
Authors: Mantler M. , Taut T.
Published: May 2005

Metallic shred obtained by turning bulk copper, brass and steel was embedded in resin and count rates were measured from these specimens and from the original bulk material. The specimens were then sliced into 0.5 mm thick sheets parallel to the plane of the x‐ray beams and the distribution of the metal within each cut was mapped by an optical scanner. Fundamental parameter calculations were applied to compute the count rates from the shred specimens pixel by pixel according to the map and also the count rate ratios relative to the bulk material of the same composition. Whereas count rates between different measurement positions may vary by more than an order of magnitude owing to the statistical distribution of the metal grains, the computed values agree to within (typically) 10% (relative) with the experimental data from matching specimen areas.
Application of X‐ray fluorescence spectrometry to the analysis of geochemical prospecting samples in China
Authors: Ma Guangzu , Li Guohui
Published: May 2005

The application of x‐ray fluorescence analysis to multi‐element determination in geochemical prospecting samples has been discussed in this paper. It consists of seven parts: introduction; sample preparation; instrument and analytical conditions; standardization and standardized sample; matrix effect correction; correction of spectral overlap; and conclusion.
Determination of Y, Zr, Ba, La and Ce in granitic rocks using energy‐dispersive X‐ray fluorescence
Authors: Lodha G. S. , Sawhney K. J. S. , Choubey V. M.
Published: May 2005

High atomic number trace elements in granitic rocks were determined using an EDXRF spectrometer. The K series x‐rays of these elements were excited using 59.6‐keV gamma rays from 241Am. Minimal sample preparation is required and quantitative determination was achieved using a single geological standard.
A low dilution fusion technique for the analysis of geological samples 1—method and trace element analysis
Authors: Eastell J. , Willis J. P.
Published: May 2005

A low dilution fusion (LDF) technique using a 2:1 flux‐to‐sample ratio has been developed for the accurate determination of major, minor and trace elements in rock samples by wavelength‐dispersive x‐ray fluorescence spectrometry (XRFS). The choice of flux, oxidant and the dilution ratio and the application to trace element analysis are discussed. The elimination of particle size effects in the homogeneous glass fusion discs is a major advantage over the use of powder pellets, especially for the determination of elements such as Ba, Cr and the REEs. The fusion technique ensures complete loss of volatiles from the rock samples and provides an accurate estimation of loss on fusion values. The oxidation and retention of sulphur in the discs were also investigated. Instrumental conditions, including corrections for spectral line interferences, are reported for 20 trace elements. The average relative error for the trace elements commonly analysed in rock samples was less than 5% and there was a decrease in sensitivity by about a factor of 2 compared with XRFS determinations on powder pellets. The LDF method has been used for the analysis of geological samples of widely varying and unusual composition, such as lamproites and kimberlites, but is also suitable as a general‐purpose sample preparation technique.
New horizons in x‐ray fluorescence analysis
Authors: Gilfrich John V.
Published: May 2005

Although the present‐day x‐ray analyst has at his or her disposal a sufficient variety of instrumentation and data reduction schemes to enable him or her to perform elemental analysis on many different types of materials, there exists a continuing demand to improve detection limits, to extend the capability to lower atomic numbers and to make the analytical process more efficient (easier!). There are advances in x‐ray physics and instrumentation being pursued which may contribute to these objectives. The status of these efforts is reviewed and some suggestions are made concerning their potential.
Combined energy‐dispersive–wavelength‐dispersive quantitative electron microprobe analysis
Authors: Ware N. G.
Published: May 2005

An empirical study of the precision of measurement by energy‐dispersive (EDS) and wavelength‐dispersive (WDS) techniques is described. Combined EDS–WDS quantitative analysis provides efficient instrument operation, optimum precision in major element analysis and the best limits of detection in trace element analysis. A software package for a combination EDS–WDS electron microprobe is described.
Study of the effect of sample, loading heterogeneity in the energy‐dispersive x‐ray fluorescence analysis of specimens of intermediate thickness
Authors: Markowicz Andrzej , Abdunnabi Ashur A.
Published: May 2005

The influence of the effect of sample loading heterogeneity on the accuracy of the emission–transmission technique applied in the x‐ray fluorescence analysis of specimens of intermediate thickness was studied. Various types of sample loading heterogeneities, including incompletely loaded samples, were considered. General expressions describing the accuracy of the emission–transmission method within a wide range of sample thicknesses and characteristic x‐ray energies were derived. Experiments for the verification of the theoretical predictions were also carried out for some selected test samples of known sample loading inhomogeneity.
Calculation of depth distribution functions for characteristic x‐radiation using an electron scattering model. I—theory
Authors: August Hans‐Jürgen , Wernisch Johann
Published: May 2005

The depth distribution function for characteristic x‐radiation is calculated using a simple electron scattering model, which quantifies the amount of electrons being scattered back and forth in the sample. The quantities used for the calculation are the transmission and backscattering coefficients, the corresponding energy and angular distributions and the ionization cross‐section. The physical background and implications of this model are discussed.
Application of x‐ray fluorescence spectrometry in process control in sinter plants
Authors: Subrahmanyam V. V. V. , Krishnaiah K. S. R. , Srivastava Y. P.
Published: May 2005

The importance of the analysis of the green mix in the operation of sinter plants in integrated steel plants is described. The application of XRF in process control of sinter plants was investigated. The results suggest the replacement of time‐consuming wet chemical methods by a combination of XRF and IR absorption techniques.
Multi‐element trace analysis of rocks and soils by EDXRF using polarized radiation
Authors: Heckel J. , Brumme M. , Weinert A. , Irmer K.
Published: May 2005

An XRF device using polarized x‐rays for trace element analysis of rocks and soils has been developed. During a measuring time of 1000 s (two single measurements of 750 and 250 s, respectively), 36 elements with atomic numbers 22 ≤ Z ≤ 92 and detection limits between 15 and 0.3 ppm can be determined with high precision. The ratio between the net counts from a characteristic line of the element being determined and the number of background counts caused mainly by Compton scattering is used for the matrix correction procedure. Absorption and enhancement effects by major sample element concentrations are taken into account. Good agreement was found between analytical results and certified values for standard reference materials.
Beam profile studies in an x‐ray fluorescence spectrometer
Authors: Boman J. , Standzenieks P. , Selin E.
Published: May 2005

For small samples, the beam intensity in a secondary target conventional x‐ray fluorescence (XRF) spectrometer is often not sufficient. As a step in our efforts to optimize the three‐axial XRF spectrometer in Gothenburg, the intensity profile of the x‐ray beam from the secondary target was studied. The intensity profile was found to be inhomogeneous. For the beam profile studies, mechanical systems were built which can also be used for position determination of small samples. A movable platform for the detector was constructed and equipped with driving and controlling electronics. To improve further the flexibility of the spectrometer, the sample holder was rebuilt to allow for movements of the sample in the x‐, y‐ and z‐directions. The possibility of tilting the sample and thus varying the angle between the incoming beam and the sample plane from about 0 to 90° was included in the mechanics of the sample holder. The arrangement can also be used to centre the samples in the spectrometer and to move the sample for analysis of different parts of the sample.
X‐ray fluorescence determination of trace elements in geological materials: An iterative approach to compton scatter corrections for matrix absorption
Authors: Harvey P. K.
Published: May 2005

Compton scatter corrections are widely used for trace element determinations in geological materials where elements heavier than iron commonly occur only in low concentrations and whose effects on matrix absorption are usually ignored. Problems with the Compton correction for absorption can be seen if the concentrations of these trace elements become anomalously large, perhaps up to a few percent, although the effects can actually become significant at only a few hundred parts per million. When this occurs the simple absorption relationship, estimated at the Compton wavelength, becomes distorted. An iterative algorithm is presented that corrects absorption ratios at any wavelength as absorption edges are encountered during processing and in turn extends the Compton method to the accurate determination of anomalously high trace element concentrations.
X‐ray fluorescence analysis of rocks by the fundamental parameter method
Authors: Afonin V. P. , Finkelshtein A. L. , Borkhodoev V. J. , Gunicheva T. N.
Published: May 2005

Improvements to the fundamental parameter algorithm of x‐ray fluorescence analysis are considered. The algorithm involves the following effects: primary and secondary x‐ray absorption, secondary and tertiary fluorescence, excitation by scattered x‐rays, excitation by photoelectrons and excitation by the divergent primary beam. The algorithm allows one to calculate the spectral intensity of x‐ray tubes with both thick and electron transmission targets. A version of the algorithm that can be handled on a low‐capacity computer is proposed. The algorithm was tested experimentally on the analysis of rocks, but its algorithm may be applied to different substances and materials.
Iodine determination in photographic fixers by energy‐dispersive x‐ray fluorescence
Authors: Morse Mark A.
Published: May 2005

An energy‐dispersive x‐ray fluorescence method is described for the determination of iodine in seasoned photographic fixing solutions. The method employs a cesium internal standard and is intended to cover a concentration range of ca. 80–4000 μg g−1 iodine. The precision [relative standard deviation (RSD)] of the iodine measurement was found to be 1.01% (1s) at the 2700 μg g−1 level. The RSD of the fixer sample preparation was determined to be 0.79% (1s). The limit of detection for iodine was calculated to be 8.7 μg g−1 (3s).
X‐ray analysis of thin GexCyOz: H films
Authors: Ebel M. F. , Ebel H. , Mantler M. , Wernisch J. , Svagera R. , Gazicki M. , Olcaytug F. , Schalko J. , Kohl F. , Jachimowicz A.
Published: May 2005

Investigations by means of x‐ray photoelectron spectrometry, electron probe microanalysis, x‐ray fluorescence analysis, imaging x‐ray fluorescence analysis, x‐ray diffraction and secondary ion mass spectrometry were performed to quantify thin GexCyOz: H films. The films were prepared by r.f. plasma deposition of tetraethylgermanium in a parallel‐plate system and in a two‐rod discharge system with magnetron enhancement. The results of these investigations indicated that depth profiling delivers a homogeneous composition, with the exception of the outermost surface. At a constant flow‐rate of tetraethylgermanium, the film density and the Ge/C atomic ration increase with increasing r.f. power density towards a maximum of 3.5 g cm−3 and 0.5, respectively. The hydrogen content does not change significantly. At low r.f. power densities there is a considerable increase in oxygen. There is no evidence for crystalline germanium carbide. Magnetron enhancement causes an increasing deposition rate and an inhomogeneous deposition in the lateral direction of the films.
X‐ray fluorescence intensity of an element in multicomponent ores and the use of compton radiation for matrix effect correction
Authors: Domi Nuri
Published: May 2005

A theoretical justification of an equation in which the matrix effects are corrected using the Compton peak, for thick specimens, is proposed. For the sake of experimental assessment with the same set of specimens but different spectrometers (wavelength‐ and energy‐dispersive), an intercomparison between ten models used for the determination of iron, copper, zinc and lead in polymetallic ores is presented.
Accuracy of calibration procedure for energy‐dispersive x‐ray fluorescence spectrometry
Authors: Markowicz A. , Haselberger N. , Mulenga P.
Published: May 2005

The quality of a calibration procedure was studies in terms of the accuracy of the calibration factors. In particular, the influence of the uncertainties of the incident and emerging angles and of the mass absorption coefficients on the calibration factors was described theoretically for a calibration procedure based on standard samples of any thickness. The calculations were carried out for an x‐ray tube and a radioisotope excitation set‐up. Practical consequences of the inaccuracies of the calibration factors were also demostrated for a few test samples of intermediate thickness analysed by the emission–transmission method.
Calculation of x‐ray fluorescence and scattered primary radiation intensitie in x‐ray fluorescence analysis of powder slurry‐like materials
Authors: Finkelshtein A. L. , Gunicheva T. N. , Kalughin A. G. , Afonin V. P.
Published: May 2005

Analytical equations for calculating x‐ray fluorescence and scattered primary radiation intensities in x‐ray fluorescence analysis of slurries and slurry‐like materials are proposed. These equations are derived for the slurry model, in which the space distribution of the solid‐phase particles is described by Poisson's law. The computation results are compared with literature data and the authors' experience.