bluuebunny/crossref_metadata_2025 huggingface dataset:
Empirical matrix corrections in practical X‐ray spectroscopy
Authors: Plesch R.
Published: May 2005

The empirical determination of the correction coefficients makes it possible to include into their values all actual changes in the measuring technique which affect the correction. It is neither necessary nor favourable to use all matrix elements for the correction. Therefore, selection criteria are given which allow arrangement of the matrix elements according to their importance to the correction.

The correction strategy is described with the aid of two practical examples: a good agreement is found between theory and practice.
Trace level water analysis by energy dispersive X‐ray fluorescence
Authors: Carlton D. T. , Russ J. C.
Published: May 2005

Analysis of dissolved elements in fresh water at concentrations from parts per billion to the high parts per million range can be carried out using 200–500 ml sampling volumes. Preconcentration using ion‐exchange resin‐loaded filter papers is automatically and quickly carried out and the prepared and dried filters analyzed by energy dispersive X‐ray fluorescence analysis. Excitation by a filtered low power tube, subtraction of a blank filter paper spectrum, automatic computer stripping of peak overlaps and removal of spectrum background gives net elemental counts that can be used with linear calibration curves to directly obtain concentration values. The system and approach readily lend themselves to laboratory use as well as unattended operation.
X‐ray methods for the determination of the amount of glass phase in mullite refractory grog
Authors: Knudsen Torben
Published: May 2005

Two different methods were used to determine the amount of glass phase in mullite refractory grog. Quantitative X‐ray diffractometry with calcium fluoride as an internal standard, was used to determine the amount of the crystalline phases, mullite and α‐corundum. The amount of glass phase was calculated as the difference from 100%. The other method used the scanning electron microscope, equipped with an energy‐dispersive detector. Samples consisting of polished sections were analysed both in the scanning mode and with the spot situated in the glass phase. The bulk chemical composition and the chemical composition of the glass phase thus found, was used to calculate the amount of glass phase in the samples. Agreement within the estimated uncertainties of the two methods was achieved with three different samples.
Die hybride Matrixkorrektur in der Röntgenspektrometrie
Authors: Plesch R.
Published: May 2005

Es wird gelegentlich empfohlen, in die Ansätze für die empirische Matrixkorrektur auch fremdbestimmte – etwa theoretisch berechnete – Koeffizienten aufzunehmen. Man erhalte damit geringere Fehler oder komme mit weniger Standards aus. Es wird gezeigt. daß diese Überlegungen auf einem Trugschluß beruhen. Zur Beurteilung der VOrzüge eines solches Verfahrens der hybriden Matrixkorrektur muβ man seinen durchschnittlichen Fehler heranziehen, wobei man erkennt, daß allgemeine Aussagen der geschilderten Art nicht gemacht werden können.
Quantitative X‐ray diffraction analysis by a direct calculation method
Authors: Hooton D. H. , Giorgetta N. E.
Published: May 2005

A new quantitative X‐ray diffraction technique has been developed by examining the theoretical basis of X‐ray diffraction originally outlined by Alexander and Klug. The new technique is based on the assumption that all components are identifiable and are to be analysed for, and avoids the use of internal standards, calibration curves, or mass absorption coefficient measurements.
Plant analyses by X‐ray spectrometry II—Elements of atomic number greater than 20
Authors: Hutton J. T. , Norrish K.
Published: May 2005

X‐ray spectrometry can be used to analyse plants for elements of atomic number greater than 20 at concentrations as low as 1 ppm. The most accurate results are obtained by measuring peak intensity, background intensity and the mass absorption coefficient of the sample. The intensity of the Compton scatter by the sample of the Au Lα from the X‐ray tube can be used as an indirect measure of the mass absorption coefficient, or this coefficient can be calculated if the concentrations of the major elements are known. Background intensity should be measured on each sample for each element but, if not practicable, e.g. in multi‐channel instruments, then a close approximation of this intensity can be calculated from the mass absorption coefficient.

Calibration has been made using chemicals added to cellulose and the results obtained for the concentration of manganese, iron, copper and zinc in a series of plant samples and in the standard kale sample are in close agreement with the chemical values.
An intercomparison of trace element excitation methods for energy‐dispersive fluorescence analyzers
Authors: Gedcke D. A. , Elad E. , Denee P. B.
Published: May 2005

The characteristics of commonly used trace element excitation methods are compared. Detection limits measured on four different instruments show that 15 kV broadband excitation is optimum for light element excitation, while monochromatic excitation is best for the 5–30 keV energy range. For simultaneous analysis of a wide range of elements, 50 kV broadband excitation is superior to monochromatic excitation.

Three different monochromatic excitation methods were studied: the regenerative monochromator filter, the secondary fluorescer and the graphite monochromator. All three methods yielded approximately the same detection limits in the 5–30 keV range, with the Si(Li) X‐ray spectrometer performance being the limiting factor.
Hybride Röntgenfluoreszenzanalyse
Authors: Kramer J. , Ebel H. , Tschismarov F.
Published: May 2005

Die Analyse mit Hilfe fundamentaler Parameter baut auf den theoretischen Zusammenhängen zwischen der Fluoreszenzzählrate, der Probenzusammensetzung und fundamentaler Grössen auf und gestattet unter Verwendung von Referenzproben Analysengenauigkeiten von grössenordnungsmassig einem Gewichtsprozent. Bei den empirischen Koeffizientenmethoden ergeben unter Verwendung einer grösseren Zahl von Referenzproben die Analysen eine um etwa eine Grössenordnung bessere Genauigkeit. Werden in dem von Lachance‐Trail1 angegebenen Linearsystem die Koeffizienten auf ihre physikalische Bedeutung hin untersucht, so zeigt es sich, dass sie in eindeutiger Weise mittels fundamentaler Parameter zu interpretieren und damit die Referenzprobenzahl auf eine einzige reduziert werden kann. Die an die theoretischen Überlegungen angeschlossenen experimentellen Untersuchungen an einer grösseren Zahl von Stahl‐ und Zementproben bestätigen die Zulässigkeit dieser Kombination und führten in den behandelten Fällen zu einer Genauigkeit von ±0,3 Gewichtsprozent im ganzen Konzentrationsbereich, also einem Wert, der zwischen den beiden oben genannten Schranken liegt.
Processing of energy‐dispersive X‐ray spectra
Authors: Russ J. C.
Published: May 2005

Much attention has been given to the treatment of energy‐dispersive X‐ray spectra. Descriptions of mathematical approaches (and their implementation in computer programs) have dealt with the major areas of separating peaks from background and from each other. There has been an unspoken but widely accepted underlying assumption that the more complex the approach, and the more general it seems to be, the better. This assumption appeals to the mathematicians and programmers but should be sharply challenged by users, whose focus is more properly the analytical results that can be obtained in specific circumstances.
The absolute determination of the reflection integral of Bragg X‐ray analyser crystals. Two‐reflection methods
Authors: Evans Kenton D. , Leigh Bryan , Lewis Margaret
Published: May 2005

The use of the two‐reflection system for the measurement of the reflection integral of Bragg X‐ray analyser crystals is investigated. Several procedures are developed and shown to produce results consistent with previously reported single reflection measurements. The new procedures are substantially more convenient in routine use.
Rapid increase of sodium count rates during the electron microprobe analysis of sepiolite. The role of zeolitic water
Authors: Butt C. R. M. , Vigers R. B. W.
Published: May 2005

During the electron microprobe analysis of sepiolite, the net count rate for sodium increased up to sixty‐fold after fifteen minutes' exposure to the electron beam. In contrast, count rates for sodium in nepheline declined by 15% in the same period. The observed increase of sodium X‐ray intensity during analysis was greater if the specimen was uncoated, and appeared to be due to a build up of negative charge at the surface. Sodium in sepiolite is associated with zeolitic water in channels within the structure of the mineral. The zeolitic water acts as an electrolyte in which the sodium ions migrate freely; dehydration before analysis reduced the enrichment effect considerably. The mechanism differs from that of ionic migration in the solid state proposed to account for similar compositional changes in glasses.
Characteristic isochromats by photons
Authors: Lindroos M. , Graeffe G. , Karras M.
Published: May 2005

A simple method is presented for measuring photoabsorption near the K absorption edge which may provide a new tool for chemical analysis. The excitation is caused by a monochromatic X‐ray beam and the emitted characteristic X‐rays are monitored as a function of the excitation energy. Simple, thick targets can be studied and only the usual type of fluorescence spectrometer is employed. The K edges of Cr, Ti and V and their compounds are studied and information is found to be available on both the concentration and chemical environment of the studied element. The chemical shifts of the half intensity of the absorption jump are presented.
Matrix effect corrections by Ag Kα Compton scattered radiation in the analysis of rock samples for trace elements
Authors: Leoni Leonardo , Saitta Maurizio
Published: May 2005

Analyses of briquetted rock samples for trace elements were carried out utilizing experimental mass absorption coefficients computed by Ag Kα Compton scattered intensity. Matrix effect corrections were applied to characteristic lines shorter than λ = 1.743 (a wavelength corresponding to the absorption edge of iron) as well as, by knowing the iron contents, to characteristic lines occurring between the absorption edge of iron and calcium. The following trace elements were analysed: Sc, V, Cr, Co, Ni, Rb, Sr, Nb, Cs, Ba, La, Ce, Pr, Nd, Pb and Th. Data on 24 international standards of rocks are reported.
Determination of uraniim in aqueous solution by X‐ray fluorescence
Authors: Barrios Nelson , Morel Oscar , Zlósilo Mario , Schlein Werner
Published: May 2005

Anlysis of uranium (VI) by X‐ray fluorescence methods, using selective solvent extraction with tri‐n‐ octulphosphin‐oxide (TOPO) has been studied. The analysis of uranium in copper leach solutions has proved successful and results indicate that this method can be used for uranium levels doen to 3ppm. The coefficient of variation (CV) at a value of 30 ppm was calculated to be CV = 2.6%.
Automatic X‐ray fluorescence analysis using CAMAC
Authors: Rucklidge J. C.
Published: May 2005

A Siemens SRS X‐ray spectrometer, with 10 sample chamber has been interfaced to a PDP11/10 mini‐computer through a CAMAC interface. Digital Equipment Corporation's RT11 operating system is used to support the Fortran programs which run the instrument. Advantages of this arrangement are: (1) The CAMAC modular interface philosophy makes simple any hardware re‐arrangements and extension to other instrument; (2) High level language programs are easily written for instrument control, data collection and processing; and (3) Simple English language dialogue via an inexpensive television console makes operation possible by all levels of personnel.
Modifications to an electron microprobe to aid in the determination of low atomic number elements
Authors: Borile Flavio , Garulli Alberto
Published: May 2005

The design and installation of a cold trap system is described specifically with reference to its use in ameliorating analysis for low atomic number elements. This trap has been mounted aon an A.R.L. EMX instrument and its use in the analysis of carbon has been investigated. This paper also discusses the metallurgical and metallographic preparation of standards for carbon analysis along with matrix correction procedures for quantitative analysis.
Elemental X‐ray mapping of cementitious phases using an energy‐dispersive spectrometer in the scanning electron microscope
Authors: Barnes P. , Moore N. T. , Sarkar S. L.
Published: May 2005

Elemental X‐Ray mappings on Portland cement clinkers have been obtained using a scaning electron microscope‐energy dispersive system (SEM‐EDS). Using this method, elemental mapping of the major constituents of cement (Ca, Si, Al, Fe) can be generated in as little as 300 s, while the minor constituents(<10%) Such as Na, Mg, P, S, K yield poorer contrast mappings. The technique used and the resultant mappings obtained are discussed.
A soft X‐ray spectrometer for the study of plutonium and plutonium‐based materials
Authors: Wallance P. L. , Haugen W. L. , Gullikson E. M. , Henke B. L.
Published: May 2005

A low‐energy spectrometer for the X‐ray analysis of plutonium and plutonium‐containing materials has been built. We use ultra‐thin window to maintain different pressures and contamination level in the spectrometers's sample and crystal chambers. Ultra‐thin windows are also used on the X‐ray tube and detector. Methods have been developed by which the spectrometer can analyze both metal and loose‐powder samples. Representative calibration spectra are presented for the fluorine band in polyfluoroethylene, the oxygen band in α‐Al2 O3, and the carbon band in graphite. Experimental spectra are presented for the fluorine band in PuF3 and for the oxygen ban in PuO2.
A new approach to the intensity correction for matrix effects in the X‐ray fluorescence analysis of ores
Authors: Kirchmayer Maciej , Dziunikowski Bohdan
Published: May 2005

Some new intensity correction models are derived based on the Lanchance–Traill set of equations and the nomographic interpretation of matrix effects. The correction models proposed in the present paper are checked experimentally using the artificial samples containing iron, zinc and lead oxides in a natural dolomite. Experiments were carried out on a multi‐channel X‐ray spectrometer with a Si(Li) detector and a 238 Pu radioactive source.

The accuracy of determination achieved with the use of correction equations presented here is compared with the accuracy attinable after using several mathematical procedures known from the literature. The results presented show the great applicability of the proposed methods.
Mathematical matrix correction in isotope‐induced low‐resolution X‐ray flourescence analysis
Authors: Dziunikowski Bohdan , Kirchmayer Maciej
Published: May 2005

A new method of characteristic line selection that allows mathematical correction procedures to be extended to portable radioisotope analysers is presented and examined. The method uses half the number of X‐ray filters used in the balanced filter method when applied to multi‐component samples. Several variants of this method are shown examined, each of them exhibiting a better accracy and a shorter time of analysis than the original filter method.
The calibration of an automatic X‐ray spectrometer using calculated relative intensities
Authors: Chamberlain G. T.
Published: May 2005

It is demonstrated that an evalution procedure for conversion X‐ray intensity to element concentration used on an existing spectrometer can be used in reverse to provide intensity data for calibrating another spectrometer. Extensive remeasurement o standards is therby eliminated. Intensities are calulated for postulated changes in compostion and these form the input data for the spectrometer computer regression program. Such data are free from measurement error. Calibration and α coefficents from claulated intensities are found to give analytical results of an accuracy comparable with those derived from experimentally produced calibration. The intensity calculations can be extended to include the determination of calibration and α coefficents without using the sepctrometyer regression programs. Considedrable expense and effort can be saved.
Enhanced resolution for X‐ray spectrometry using a commercial spectrometer
Authors: Haycock D. E. , Urch D. S.
Published: May 2005

Mathermatical techniques (Fourier transform and iterative procedures) are described for unfolding spectrometer broadening from observed X‐ray emission peaks. This enables enhanced resolution to be obtained. Broadening introduced by soller collimators and by crystal imperfections are considered in detail. Low energy peak ‘tailing’ due to beam divergence in the plane of the soller slits is also discussed.
Measurement of K‐shell flourescence yield and Kα/Kβ intensity ratio for nickel
Authors: Keith H. D. , Loomis T. C.
Published: May 2005

For application for the fundamental parameter approach to quantitative chemical analysis of mixtures by X‐ray fluorescence, accrate knowledge is required of fluroescence yields and ralative intensities of X‐ray lines of the various elements involved. The spread in published data suggests, however, that these parameters are not known with as much accuracy as could be used profitably. In this paper we describe a method by which K‐shell flurescence yield and Kα/Kβ intensity ratio can both be measured in the same experiment to within approximately 0.5% for pure elements available as thin polcrystalline foil. Results are given for the particular case of nickel (Z=28) for which we find ωK = 0.452 ± 0.002 and Kα/Kβ=6.91 ± 0.335, but the method is readily applicable to anty element whose atomic number falls in the approximate range 20 ≲ Z ≲ 50 and which can be obtained in suitable physical form. A key factor in the experimental design is use of a non‐dispersive (intrinsic germanium) X‐ray analyzer; this makes it possible to employ a very simple transmission geometry which can be characterized quite precisely. Experimental conditions, and precautions needed to obtain accurate and consistant results, are described in some detail. Among other corrections applied, allowance is made for scattering of both exciting statistics and residual uncertaintes incalculating corrections for scattering. Among these residual uncertainties are errors in correcting scattering coefficients for anomalous dispersion. Such errors are significant only when evaluating fK, the K‐shell excitation efficienvcy; the important product fK ωK can, however, be determined (fKωK = 0.398 ± 0.002) with greater reliability than ωK itself.
A focusing X‐ray polarizer for energy‐dispersive analysis
Authors: Ong Poen S. , Randall John N.
Published: May 2005

The Properties of diffracting crystals a Bragg and of near 45° are studied for use as an X‐ray polarizer. Such crystals have many advantages over the Barkla type polarizer when used in an energy‐dispersive X‐ray analyzer. The study shows that many matching λ‐d combinations are available, but the present work was done with LiF (200). With this crystal, the second order diffraction of Cu Kβ radiation occurs at 43.67° and an improvement of peak to background ratio by a factor 45 was obtained. The study revealed that a substantial improvement of peak to minimum detection limit can be obtained with a larger deviation of the polarization angle, as long as this deviation is accompanied by a higher X‐ray output.
A fast and simple procedure for the evaluation of net intensities from energy‐dispersive X‐ray spectra
Authors: Ekelund S. , Thurén A. , Werlefors T.
Published: May 2005

A procedure has been developed for extracting net peak intensities from electron‐beam‐induced energy‐dispersive X‐ray spectra. The procedure has been implemented in a computer program which requires very modest storage capacity of a minicomputer, yet can be executed in a few seconds to yield net intensities. The program structure is simple. Provided the peak to background ratio is better than ∼5 to 1 the intensities are adequate for correction to quantitative analysis with accuracies comparable with more sophisticated and time‐consuming methods. The procedure has been used extensively on a computer‐controlled scanning electron microscope to give rapid information from complicated spectra.
Loss of sulphur during irradiation of X‐ray spectrometric standards prepared using cellulose and poly(vinyl alcohol)
Authors: King R. T.
Published: May 2005

A loss of sulphur Kα intensity was observed during irradiation of pellets containing some sulphur compounds in organic binders. For elemental sulphur and dibenzyl disulphide mixed with either cellulose or poly(vinyl alcohol), the loss of intensity is attributed to loss of sulphur following reaction with hydrogen produced by radiolysis of the organic binder. No such loss is observed from potassium aluminium sulphate in either binder. The rate of loss of sulphur per unit of energy absorbed by the sample accords with published values for hydrogen production by radiolysis of carbohydrates and alcohols.
Instrumental interferences in X‐ray fluorescence analysis of thin samples
Authors: Bonner Norman A.
Published: May 2005

A method is described for correcting X‐ray fluorescence spectra for the presence of instrumental interference peaks. The method applies particularly to the analysis of samples which are not infinitely thick. The intensities of coherently and incoherently scattered exciter radiation are used to determine the variable intensity of the interference peaks.
Response functions for the quantitative evaluation of compromise conditions for multi‐element analyses with energy‐dispersive X‐ray fluorescence spectrometry
Authors: Wegscheider Wolfhard , Jablonski Bruce B. , Leyden Donald E.
Published: May 2005

Figures‐of‐merit are developed for simultaneous multi‐element analysis with energy‐dispersive X‐ray fluorescence spectrometry. Those derived from information theory frequently give optima in regions of poor excitation of one or more elements and have to be restricted to the region above the absorption edge of the highest Z element; the shapes of the surface described by these and other functions are studied and their optima are compared. A product sum function of inverse Poisson standard deviation gives results that best meet the expectations of X‐ray spectroscopists. The location of optima in the space of excitation conditions is dependent upon concentration, but the optimum of the one sample of a batch with the highest overall count rate is still a good compromise between the best experimental conditions and maximum input. These results are substantiated with plots giving the dependence of the figures‐of‐merit from experimental conditions and with spectra at the optima as defined by the different functions. These equations are potentially useful as objective functions in optimization alogorithms as well as for the comparison between the performance of different X‐ray systems.
Totalreflexions‐Röntgenfluoreszenzanalyse
Authors: Wobrauschek P. , Aiginger H.
Published: May 2005

Energiedispersive Röntgenfluoreszenzanalyse ermöglicht die rasche und gleichzeitige Bestimmung verschiedener Elemente in einer Probe. Die bei Winkeln von einigen Minuten auftretende Totalreflexion von Röntgenstrahlen an der polierten Oberfläche eines Probenträgers, z.B. Quarzglas, und eine spezielle Geometrie‐Primärstrahl‐Probe‐Detektor wird dazu verwendet, um den durch klassische und Compton‐Streuung hervorgerufenen Hintergrund zu senken. Dadurch konnten Nachweisgrenzen für Elemente mittlerer Ordnungszahl im Nanogrammbereich erzielt werden. Tritt Totalreflexion von Röntgenstrahlen auf, so dringen diese nur in einer Tiefe von etwa 40–70 nm in den Probenträger ein und bestimmen dadurch die effektive Dicke. Man verbindet daher mechanische Festigkeit, chemische Widerstandsfähigkeit und beliebige Dimensionierung des Probenträgers mit den für geringen Hintergrund günstigen Eigenschaften extrem dünner Folien. Standardmeßzeiten von 120s und ein Probenvolumen von 5 μl sind ausreichend, um Konzentrationen im ppm Bereich, d.h. Absolutmengen von Nanogramm mit RFA nachzuweisen.
The PIXE facility at Eindhoven University of Technology
Authors: van der Heide J. A. , Kivits H. P. M. , Beuzekom D. C.
Published: May 2005

A new facility for particle‐induced X‐ray emission analysis is presented. The performance of an on‐demand beam pulsing system is checked experimentally and results of some calculations are shown graphically.
X‐Ray fluorescence analysis in the X‐ray region of 0.4 to 7 nm: Application to determination of fluorine in slags
Authors: Sato Kimitaka , Tanaka Isamu , Otsuki Takashi
Published: May 2005

X‐ray fluorescence analysis under high vacuum (∼10−6 torr) was applied to the determination of fluorine in slags. Slag samples are converted into glass beads using a fusion method and the fluorescent X‐ray intensity of characteristic X‐ray F Kα (1.83 nm) is measured to determine fluorine. The calibration curve has excellent linearity and accuracy; σd is 0.18% for 11 kinds of samples involving fluorine of 0.10% to 16.78% (mean: 6.96%).
Influence of divergence of the primary radiation beam on the line intensity of the X‐ray fluorescence spectrum
Authors: Pavlinsky G. V. , Kitov B. I.
Published: May 2005

X‐ray fluorescence spectrum excitation theory is now well developed and uses the assumption that the primary X‐ray radiation beam is parallel. At the same time, in order to increase intensity it is necessary to keep the radiation source and fluorescence object as close as possible. In so doing the primary radiation divergence is found to be significant, and to ensure high accuracy of the intensity calculations it is necessary to evaluate the influence of this factor.

Considerations are carried out for the cases of point, circular and line sources of primary radiation, selective effects being absent.

The concept of the effective incidence angle is introduced which makes it possible to calculate X‐ray fluorescence intensities by formulae without correction for the primary radiation divergence. Values of the correction coefficients are given which correct for the dependence of the effective angle on chemical composition of the fluorescence material. The value of the effective incidence angle of primary radiation for a circular source is determined and compared with its theoretical value. Statistical treatment of the results shows insignificant differences between the experimental intensities and those calculated with correction for the primary radiation divergence when chemical composition variation of the material analysed is quite large.
Linear and non‐linear peak fitting in energy‐dispersive X‐ray fluorescence
Authors: Nullens H. , Van Espen P. , Adams F.
Published: May 2005

Linear and non‐linear least‐squares fitting procedures are compared in their ability to resolve X‐ray fluorescence spectra obtained with Si(Li) detectors. It is shown, by repeated analysis of synthetic and real X‐ray spectra, that non‐linear least‐squares fitting programs which take into account the relation between peak positions and widths on the one hand and X‐ray energies on the other hand, and moreover impose limitations upon the fitting parameters, represent a definite advantage over the linear least‐squares fitting method. Only for spectrometers having an extremely high stability with time and counting rate does the linear fitting procedure yield accurate results.
Optimization of a spectrometer for energy‐dispersive X‐ray fluorescence analysis by X‐ray tubes in combination with secondary targets for multielement determination
Authors: Spatz R. , Lieser K. H.
Published: May 2005

The construction of a simple device for X‐ray fluorescence analysis by use of an X‐ray tube, secondary targets and filters is described. Optimal conditions and detection limits are determined experimentally by variation of the excitation parameters for each combination of secondary target and filter.
Determination of tungsten in ores, concentrates and plant process materials using internal standard X‐ray fluorescence spectrophotometry
Authors: Harris A. M. , Hingle D. N.
Published: May 2005

A method is described for the X‐ray fluorescence determination of tungsten in non‐metallic samples over the range 0–100%. The sample is fused with (65% sodium, 35% lithium) tetraborate, barium nitrate and tantalum pentoxide, the internal standard, at 1200°C and the melt cast into a platinum/5% gold mould. After cooling the cast bead, the tungsten and tantalum Lα intensities are determined by X‐ray fluorescence. The tungsten content of the sample is found by comparing the measured intensity ratio with intensity ratios obtained from standards prepared using pure tungsten trioxide.

A wide range of ores, concentrates and plant process materials are analysed for tungsten by this method. The accuracy and precision of the method, which is quicker and requires less skill from the analyst, are found to be superior to those of the classical gravimetric method.
An estimation of selected methods for the correction of interelement effects in X‐ray fluorescence analysis
Authors: Stankiewicz W. , Sanner G.
Published: May 2005

The comparison of the efficiency of the selected interelement effect correction methods was the aim of this paper. The experiments were carried out on the synthetic oxide samples containing 0–40% PbO2, 20–60% ZnO, 0–40% Fe2O3 and 0–30% SiO2. The existing strong interelement effects were evaluated by means of the Plesch criterion. In order to find the correction method giving the best results and at the same time being relatively simple for practical use the internal standard and several mathematical methods (de Jongh, Rasberry–Heinrich, Lucas‐Tooth–Pyne, and regression) were accurately investigated. The efficiency of the selected mathematical methods was characterized by the values of relative residual variance. None of the examined methods gives the best results for all elements simultaneously. The values of relative residual variance lie between 1% and 5%. The approximation by the Rasberry–Heinrich model gives the best average variance over all elements, but its practical use is very labour‐consuming. The simple form of the Lucas‐Tooth–Pyne and regression equations as well as the relatively simple calculations provide facilities for their application in laboratories not equipped with more sophisticated calculating systems. The internal standard method gives results which are comparable with those obtained by use of the mathematical methods tested.
X‐Ray production by 11‐27 MeV alpha particles
Authors: Bǎdicǎ T. , Ciortea C. , Petrovici A. , Popescu I.
Published: May 2005

K X‐ray prodution cross‐sections for S, Cl, K, Ni, Cu, Ga, Br, Ag and Cs and total L X‐ray production cross‐sections for Cs, W and Pb using α‐particles of 11, 16, 21 and 27 MeV energy have been measured. The present results, combined with some earlier measurements, were compared with the theoretical predictions of the plane‐wave Born approximation (PWBA), binary encounter approximation (BEA) and perturbed stationary state (PSS) approximation.
Multielement x‐ray fluorescence spectrometry of solutions
Authors: Budesinsky B. W.
Published: May 2005

The theoretical relationships between fluorescence intensity and concentration have been used for the calculation of correction constants of the Lachance‐‐Traill and Rasberry‐‐Heinrich equation for systems of solutions. The constants have also been calculated by means of the multivariate least‐‐squares method. Those two alternatives have been tested on systems of Cu‐‐Fe‐‐Zn and Cu‐‐Fe‐‐Zn‐‐Pb in 3.5% aqueous nitric acid and compared with the simple two‐variable linear relationship between fluorescence intensity and concentration. The multivariate least‐‐squares alternative gives for the Lachance‐‐Traill method very accurate results (average relative deviation does not exceed 0.18%). In a theoretical discussion, the relationship between optimum sample concentration and solvent correction (enhancement) constant is shown. The optimum conditions for a background reading are also calculated.
Kβ/Kα ratios in energy‐dispersive x‐ray emission analysis
Authors: Khan Md. R. , Karimi M.
Published: May 2005

A set of most probable Kβ/Kα values estimated on the basis of all available experimental data is presented.
A peak integration method for acquiring x‐ray data for on‐line microprobe analysis
Authors: Ferguson A. K. , Sewell D. K. B.
Published: May 2005

The operation of a computer system for producing on‐line chemical analyses from a three‐spectrometer JEOL JXA‐5A electron microprobe is briefly discussed. A new method for acquiring the X‐ray data by integrating the area under the peak is discussed in greater detail. The increased reliability of the results from this new method are illustrated by considering the effect of focus error on the measured count rates.
X‐ray diffractometry of airborne particulates deposited on membrane filters
Authors: O'Connor B. H. , Jaklevic J. M.
Published: May 2005

Methods are considered for optimizing a conventional Bragg‐‐Brentano X‐ray powder diffractometer for the identification of crystalline phases in airborne particulates deposited on membrane filters. The instrumental parameters investigated include detector stepping increment and scan range, Kβ filtration, and the incident beam divergence slit width. Sample‐related factors such as substrate material (cellulose ester, polycarbonate and polytetrafluoroethylene), off‐axis displacement of the sample and X‐ray induced specimen degradation were also studied. Scan times for sample deposits of several hundred μcm−2 are in the vicinity of 24 h with an 800 W tube. These times may be reduced substantially by one or more of the following modifications: rotating anode or synchrotron radiation source, energy‐dispersive diffractometry, and Bragg‐‐Brentano diffractometry with a position‐sensitive gas detector.
Determination of the thickness of SiO2 layers on SI by X‐ray spectrometry
Authors: Ebel M. F. , Ebel H. , Wernisch J.
Published: May 2005

This paper shows the employment of five X‐ray methods for the investigation of a thickness range of 1 Å to 0.1 mm. The well known techniques (X‐ray fluorescence and scanning electron microscopy) are treated, a new method (energy‐dispersive X‐ray diffraction) is discussed and X‐ray photoelectron spectroscopy measurements are essentially improved by a new evaluation method. Low energy electron induced X‐ray spectrometry is mentioned. As far as significance of the measured thicknesses is concerned, the range of 10‐‐50 nm deserves special attention.
Automatic absorption correction in x‐ray fluorescence analysis of intermediate thickness samples using a dual external reference signal
Authors: Van Dyck P. , Markowicz A. , Van Grieken R.
Published: May 2005

A method has been investigated which allows calculations from the X‐ray fluorescence spectra of the absorption coefficients at any energy for any sample, without any additional measurement. Use is made of the ratio of the characteristic X‐ray signals from a Zr wire positioned in front of the sample and from a Pd foil placed behind the sample, both in a fixed geometry. From the experimentally measured absorption coefficient at the Pd L energy (2.9 keV), the coefficients for higher energies are calculated. By the use of an iterative computer routine in which corrections for the enhancement of the Pd foil by the sample are also included, an accuracy of 2% or better on the absorption coefficient determination can be reached for homogenous samples in one measurement. Grain‐size and heterogeneity effects induce inaccuracies on the absorption coefficient determinations which might well reach 20% for particulate samples like intermediate thickness deposits of geological materials. This approach thus has the same limitations as the classical transmission method for such heterogeneous samples.
The derivation of influence coefficients from experimental and calculated XRF data
Authors: Chamberlain G. T.
Published: May 2005

The use of the multiple linear regression program for the derivation of influence coefficients destroys the data bank in the Philips PW 1450/10 spectrometer computer and interrupts analysis. Consideration of the basis of α‐coefficients as applied to relatively dilute solutions leads to methods of avoiding the use of this program. Linear regression involving a single independent variable and simple algebraic expressions can be used to derive the coefficients. The requirements for converting α‐coefficients applicable to one solvent for use in a different solvent are described.
Computer control of the electron probe microanalyser: The control system and some applications
Authors: Bishop H. E. , Poole D. M.
Published: May 2005

The ways in which the usefulness of the electron probe X‐ray microanalyser is extended by computer control and the demands imposed on the computer operating system by a general purpose electron probe are discussed. Three main modes of operation are identified and a flexible operating system to meet the main requirements for these modes is described. Examples of the use of the system are given with particular emphasis on two applications which could not be tackled easily with a manually operated system: composition surveys over large areas of the sample and digital mapping techniques.
A method for isotope‐excited X‐ray fluorescence analysis of thick samples
Authors: Datta S. , Sadasivan S.
Published: May 2005

A simple equation relating the intensity of characteristic X‐ray lines to their respective weight fractions has been obtained for a thick sample excited by an isotopic source. It follows from the equation that a single intense line in a standard sample suffices to generate calibration constants over a wide range of elements. Validity of this aproach has been demonstrated by the analysis of a standard soil sample using only the Fe Kα line for calibration. A procedure for correction of peak overlaps has been given using the Kβ/Kα ratios, modified by the matrix effects. The method is very useful for the analysis of soil samples and can be conveniently applied to other matrices.
X‐ray fluorescence analysis without standards of small particles extracted from super‐alloys
Authors: Ohno Katsumi , Fujiwara Jun , Morimoto Ichiro
Published: May 2005

Small amounts of particulate matter electrochemically extrated from super‐alloys were accurately analysed by X‐ray fluorescence spectrometry with pure element bulk standards. The extracts are less than a few hundred micrograms per square centimeter and are not homogeneous. They are approximated by a thin film on a filter substrate. The penetration of the particulates into the membrane filter on which they are mounted is negligible and no absorption correction for the filter is required. The spectral distribution of the X‐ray source used in the calculation was obtained from Kramer's formula with self‐absorption correction for the continuum and from measurements of the characteristic line. The intensity‐concentration algorithm is based on the fundamental parameter method; the calculation is simplified because no matrix correction is required if the relative intensities are less than or equal to 0.04. The method gives excellent results in chemical analyses.
Multielement analysis of phytoplankton by tube‐excited energy‐dispersive X‐ray fluorescence
Authors: Pietiläinen K. , Adams F. , Nullens H. , Van Espen P.
Published: May 2005

Tube‐excited energy‐dispersive X‐ray fluorescence with Mo K and Ti K secondary target radiation proves to be a rapid, precise and accurate method for the multielement analysis of phytoplankton collected on membrane filters. Using 150–750 ml water samples it is possible to determine the concentration of 11–16 elements among the 22 elements which can be systematically searched for in the spectra. The study area is an estuarine water body on the Gulf of Finland and an archipelago outside the estuary.
Comparison of crystals for oxygen analysis
Authors: Barrus D. M. , Blake R. L.
Published: May 2005

A comparison is made between five acid phthalates and clinochlore as analyzer crystals for oxygen Kα emission. Thallium acid phthalate (TAP) is shown to be superior for quantitative analysis because it has high reflectivity, relatively smaller corrections to reflectivity for anomalous dispersion, relatively low high order reflectivities and relatively low fluorescence background. The interplanar 2d spacing for TAP is 25.7626 ± 0.001 Å and its coefficent of thermal expansion α is 32.7 ± 1 K−1. At the oxygen Kα position its effective 2d spacing is 25.724 Å and the mean reflection coefficient is 2.8 × 10−4 rad. For analysis of chemical state, where higher resolution is often desired to distinguish band shapes and satellites, rubidium acid phthalate (RAP) is the best choice. It has α = 37.0±3 K−1, an effective 2d spacing of 26.083 Å and a mean reflection coefficient of 8.2 × 10−5 rad.
Standardization of the peak area ratios obtained from the analysis of small glass fragments using energy‐dispersive X‐ray fluorescence spectrometers
Authors: Howden C. R. , Dudley R. J. , Smalldon K. W.
Published: May 2005

The spectral sensitivities of different energy‐dispersive X‐ray fluorescence spectrometers may vary to the extent that the same glass fragment produces noticeably different spectra. In this study a set of twelve glass standards has been prepared. These are polished glass discs which span a wide range of elemental levels, and have been prepared for the monitoring and measurement of relative instrument sensitivies. The polished discs were analysed several times in rapid succession on one instrument and the mean elemental peak area ratios obtained were designated as standard values for these samples. During subsequent routine analytical work on this and other instruments, the discs are regularly analysed and if any significant changes are found the new elemental ratios can be corrected to the standard values usually simply by multiplying by a constant (the relative sensitivity factor). The procedure is shown to be effective in the case of 14 fragments of glass weighing between 40 and 1160 μg which were analysed several months apart on two different instruments.
A correction constant for rapid microprobe analysis of multicomponent metallic systems
Authors: Kale G. B. , Khera S. K.
Published: May 2005

The evaluation of the true chemical composition of multicomponent alloys by electron probe microanalyser requires the application of several correction factors, viz. atomic number, absorption and fluorescence corrections. Calculation of these factors is dependent upon a set of empirical correlations and needs the use of a computer. An alternative simple procedure of converting raw data into true composition using constants A is presented here. The paper describes the evaluation of these A constants, by rewriting the Ziebold–Ogilivie relation in the form: k/C = A + (1− A)k, and their use in computing true compositions.
An X‐ray narrow band detector and its application to X‐ray spectral quantitative analysis
Authors: Anisovich K. V. , Komyak N. I.
Published: May 2005

An X‐ray narrow band detector based upon a selective X‐ray filter and selective secondary emitter is described. The detector transmission band makes up 0.3–1.5 Ke Vin the range 2–40 KeV. The detection efficiency of X‐rays reaches 5%, the area of the detector entrance window being 10cm2.A high luminosity of the narrow band detector makes it possible to decrease the required power of an X‐ray tube to a few watts in X‐ray spectral quantitive analysis. optimal relations between the detector elements as well as optimal conditions of fluorescence excitation are discussed. The application of the narrow band detector to X‐ray spectral quantitative analysis is illustrated.
Use of a bare CaF2 (Eu) scintillator to assess the escape peak formalism and the fundamental parameter method
Authors: Szöghy I. M.
Published: May 2005

Escape peak and thick target yield formalisms are shown to be equivalent, although experimental results using a practical source–target–detector geometry favor the latter. A bare non‐hygroscopic CaF2(Eu) scintillator is used to measure the K X‐ray yield from thick targets of pure elements excited by monoenergetic photons. The scintillator is found free of dead layer up to the limit of 0.1 μm: it can thus detect photons above 2 keV energy with intrinsic efficiency approaching 100%.
A microcomputer based control and data acquisition system for early model wavelength‐dispersive X‐ray fluorescence spectrometers
Authors: Jablonski Bruce B. , Leyden Donald E.
Published: May 2005

Early model wavelength‐dispersive X‐ray fluorescence spectrometers can be inexpensively fitted with computer capability through the use of a microcomputer. The principal advantage of the microcomputer over a minicomputer is low cost and the principal disadvantage is relatively slow computational speed. We have found that an Apple II plus microcomputer can perform all of the tasks previously assigned to a larger (and more expensive) minicomputer. Ready availability, ease of service and program flexibility make the microcomputer an attractive choice for a laboratory computer. A matrix effect correction program, XRF‐4, has been run in the microcomputer with excellent results.
Theoretical evaluation of overlap coefficients in XRF spectra
Authors: Datta S. , Sadasivan S.
Published: May 2005

An attempt has been made to obtain theoretically the overlap coefficients of interfering lines in XRF spectra. The peaks have been analytically represented by a Gaussian function and the overlap evaluated for Covell integration. The coefficients for a wide range of elements and for various detector resolutions have been computed as a function of integration window width. The variation with window width of evaluated coefficients is compared with published experimental values.
A simple method for calculating x‐ray absorption spectra for use in crystal spectrometer and mirror analysis
Authors: Shah A. , Gurman S. J.
Published: May 2005

A simple scheme is described whereby x‐ray absorption spectra, including the very strong rapidly varying structure near an absorption edge, may be calculated using only a short program and small amounts of computer time. The analysis also provides general rules for the existence of strong structures at the edge. The scheme can describe any neutral absorbing atom (or, with a little modification, ion) and includes the effect of the core hole when necessary. Fits to experiment show good agreement near absorption edges, with somewhat poorer agreement far from the edge. The method is of use in obtaining absorption spectra for use in crystal spectrometers for x‐ray mirror calculations where a knowledge of the fine detail of the absorption is not necessary, but an accurate reproduction of the major structure near the edge is.
Simultaneous multielement analysis of phosphates by x‐ray fluorescence
Authors: Issahary D. , Pelly I.
Published: May 2005

An accurate, rapid and relatively cheap method adapted for use in the phosphate industry for on‐line simultaneous multielement analysis of phosphate ore and calcined phosphate, using x‐ray fluorescence, is described. The method of analysis is sufficiently accurate for the phosphate industry, which demands great accuracy in P2O5 analysis. A statistical evaluation of precision and accuracy is given.
Energy dispersive x‐ray diffractometry: 1. The specimen transparency factor
Authors: Mantler M.
Published: May 2005

The shape of energy dispersive diffraction lines from flat powder samples is determined by the Bragg angle, beam divergences, absorption of the radiation, specimen misalignment and detector performance. Due to asymmetric line broadening, the lines appear to be shifted, usually to lower energies. Two ‘specimen transparency models’ are presented, based upon the accurate determination of line positions and line intensities that are possible.