bluuebunny/crossref_metadata_2025_split huggingface dataset:
A simple empirical inter‐element correction procedure applied to the X‐ray fluorescence analysis of nickel‐base alloys
Authors: Griffiths J. M. , Whitehead H. R. 
Published: May 2005

AbstractThe application of a simple, empirical inter‐element correction procedure to the analysis of nickel‐base alloys is described. The correction factors are considered in relation to the effects predicted from a study of the mass absorption coefficients.
Eine vereinfachte Formulierung des Korngrößeneinflusses
Authors: Weber K. 
Published: May 2005

AbstractBei geeigneter Wahl der Koeffizienten ist es Möglich, die bekannte hyperbolische Gleichung für die Röntegenspektral‐analyse des Zweistoffsystems auch im Gebiet des Korngrößen‐einflusses beizubehalten. Damit wird die experimentelle Bestimmung und Handhabung der Korngrößenparameter wesentlich vereinfacht, wie an Hand von Literaturdaten belegt wird; insbesondere ergibt sich ein Weg, den Korngrößeneinfluß von anderen Einflußfaktoren abzutrennen.
A simple method for background and matrix correction of spectral peaks in trace element determination by X‐ray fluorescence spectrometry
Authors: Feather C. E. , Willis J. P. 
Published: May 2005

AbstractBetween adjacent major element absorption edges, background intensities at differing wavelength positions were found to be related linearly. Also, background intensity at any position is linearly related to the reciprocal of the mass absorption coefficient for any wavelength between the absorption edges.The method presented here allows for the determination of background, as well as mass absorption coefficient, by a single measurement at an interference‐free background position (which can be the Compton scatter ‘peak’). If the mass absorption coefficient is already known, backgrounds may be calculated directly.Tests on geological materials show that, while not as accurate as conventional methods of background determination, relative accuracies of two to five percent are obtainable with a very considerable saving in time, since intensity at only one background position need be measured. Use of low dispersion high reflectivity analysing crystals, e.g. LiF(200), is possible because it is no longer necessary to attain interference‐free background positions between peaks.Furthermore, the method is ideally suited to the determination of background intensities in energy dispersive systems where spectral resolution is a problem and in multi‐channel units where only one channel need be used for the determination of both mass absorption coefficient and backgrounds for a group of trace elements.The method has been used in the low cost determination of trace elements in large numbers of geochemical prospecting samples.
Spectral distributions of X‐rays produced by a general electric EA 75 Cr/W tube at various applied constant voltages
Authors: Loomis T. C. , Keith H. D. 
Published: May 2005

AbstractSpectral distributions of X‐rays generated by a General Electric EA 75 Cr/W dual target X‐ray tube have been measured using exciting voltages of 20, 30, 40 45 and 50 kV c.p. A carefully characterized and previously described lithium‐drifted silicon detector was used and corrections were applied for second order effects in the detection system and for detector efficiency. Relative errors are believed to be of the order of 1% over most of the range covered (4‐50 ke V), increasing to about 10% over the lower range of photon energies (2.5‐4 ke V). Although the resolution of the detector is limited, it was nevertheless possible by computation to separate groups of characteristic spectral lines from continua and to determine self‐absorption jump ratios in these continua. Spectral distributions obtained using chromium and tungsten targets are compared with earlier data of Birks and his collaborators and with the forms of continua predicted by Kulenkampff's equation. Agreement is only fair. The experimental method employed for studying spectral distributions is believed to be the most accurate and reliable now available and is particularly convenient in terms of the rapidity with which distributions can be measured. Further work is required to remove remaining uncertainties concerning the generation of X‐rays at thick targets.
Evaluation of a practical background calculation method in X‐ray energy analysis
Authors: van Espen P. , Adams F. 
Published: May 2005

AbstractThe background beneath the fluorescence lines of energy dispersive X‐ray spectra obtained with a molybdenam secondary target tube‐excited system can be obtained from the intensities of the coherently and incoherently scattered radiation. The background intensity at a particular energy is equal to the product of a proportionality factor multiplied by the incoherently scattered radiation intensity, plus another proportionality factor multiplied by the coherently scattered radiation intensity. The proportionality factors are determined from measurements of a number of molybdenum‐loaded cellulose filters.The proposed procedure provides accurate results for the analysis of complex X‐ray spectra of thin samples of varying composition.
Empirical matrix corrections in practical X‐ray spectroscopy
Authors: Plesch R. 
Published: May 2005

AbstractThe 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

AbstractAnalysis 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

AbstractTwo 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

AbstractEs 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

AbstractA 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

AbstractX‐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

AbstractThe 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

AbstractDie 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

AbstractMuch 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

AbstractThe 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

AbstractDuring 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

AbstractA 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

AbstractAnalyses 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

AbstractAnlysis 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

AbstractA 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

AbstractThe 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

AbstractElemental 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

AbstractA 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

AbstractSome 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

AbstractA 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

AbstractIt 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

AbstractMathermatical 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

AbstractFor 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.