bluuebunny/crossref_metadata_2025_split huggingface dataset:
L'Application de la Théorie des Orbitales Moléculaires à l'Interprétation des Déplacements Chimiques et à l'Origine des Lignes Satellites à Basse Energie dans les Spectres de Rayons‐X du Silicium
Authors: Urch D. S. 
Published: May 2005

AbstractUne méthode est donnée pour l'interprétation des spectres‐X des composés par la théorie des orbitales moléculaires; enparticulaire, l'emission Kβ1,3des composés du silicium. On sait, grace de la spectroscopie photo‐électronique, que l'énergie d'ionisation du niveau 1sdu silicium s'augmente avec l'électro‐ negativité de l'autre élément,Xdans la liaison Si‐X. L'énergie d'ionisation des liaisons s̀, pour Si‐X, augmente aussi pourX= Si → O → F. Donc l'énergie de l'émission Kβ reste presque la même avec la variation deX. Mais si on peut changer l'ionicité de la liaison (avec le même ligand) on aurait, augmentation de l'énergie d'ionisation du silicium 1set diminution de l'énergie de la liaison s̀. C'est pourquoi l'énergie de la rayon‐X, Kβ est 1840 e V pour Si(CH3·CO·CH·COCH3)3+HCL2−(coordination du Si, 6) mais seulement ˜ 1835 eV pour les autres compoés avec coordination 4.
X‐ray spectroscopy on the electron microscope
Authors: Russ J. C. 
Published: May 2005

AbstractThe combination of energy dispersive X‐ray analysis with the transmission electron microscope enables the microscopist to rapidly identify features observed in the normal operation of the microscope, at high magnification. The development of equipment and techniques, especially in the art of specimen preparation, will now permit analysis of as little as 10‐18g, on a spatial scale of a few tens of nanometres. The importance of this technique in the biological and materials sciences promises to be as great as the contribution of the electron microscope itself.
Analogies between quantitative X‐ray fluorescence analysis (XRFA) and quantitative X‐ray photoelectron spectrometry (XPS)
Authors: Ebel H. , Ebel Maria F. 
Published: May 2005

AbstractThe analogies between XRFA and XPS are the basis for the development of quantitative XPS methods for solid metallic samples and also for the determination of inelastic scattering coefficients. The results of the theoretical treatment have been verified by experiments.
A simple calculation model with great versatility for interelement effects in steel by X‐ray fluorescence analysis
Authors: Dahl M. , Karlsson A. 
Published: May 2005

AbstractDemands of more rapid and accurate answers for the steel plant made it necessary to develop a computerized system for calculation and control of the analysis performed on X‐ray fluorescence and optical emission spectrometers. The interelement effects which occur in X‐ray fluorescence analysis are briefly described and the evolution of a model for these corrections is examined. This model includes corrections for absorption and secondary fluorescence as well as overlapping, dead time effects, etc. which are based on simplified theoretical formulae and can be used for a broad field of applications. The parameters in the model have been determined empirically by measuring a wide range of binary alloys. The interelement effects in optical emission analysis are calculated according to a simple emprical formula. The mathematical models have been fitted to a computer (Datasystem Trask P100) which also controls the two separate spectrometers. Examples are given of routine analysis performed by this model on bulk solids of steels and fused glassy borates of sinters, slags and hard metals. Its chief advantage is that the usual requirement for a great number of standards is eliminated.
Isotope‐excited X‐ray fluorescence analysis of binary alloys using energy dispersion
Authors: Laine E. , Tukia L. 
Published: May 2005

AbstractA radioisotope‐excited X‐ray fluorescence method for the analysis of binary alloys has been presented. In this energy dispersion analysis no standard specimens were needed. The method was applied to copper‐antimony alloys. The results were checked by another energy dispersion method based on X‐ray diffraction. X‐ray photons from the specimen were measured with an Si (Li) detector and a multichannel analyser was used to sort out the energies. The data were recorded on punched paper tape for computer processing.
Theoretical correction procedures for X‐ray fluorescence analysis
Authors: Shiraiwa Toshio , Fujino Nobukatsu 
Published: May 2005

AbstractTheoretical to formulae for the fluoresent X‐ray intenisty are obtained and calculations made for nickel + iron + chromium binary and tertiary systems. In the calculation, the continous X‐ray of the irradiating source should be taken into account. The theoretical results agree well with the experimental results but have maximum deviations of 1% and it is thought that the error may be due to coexistent elements. The effect of the coexistent elements can be estimated by theoretical calculation and in routine work the effects are usually expressed as linear expansion factors. These factors are generally obtained from a series of experiments but they can be easily obtained by calculation. The errors caused by the linear approximation are also estimated and it is concluded that the approximation is approved in routine analysis of steels when the composition ranges of the steel type are limited by industrial standards.
Quantitative analysis with an energy‐dispersive detector using a pulsed electron probe and active signal filtering
Authors: Statham P. J. , Long J. V. P. , White G. , Kandiah K. 
Published: May 2005

AbstractThe pulsed beam technique has been used to achieved a high data acuumulation rate in an energy‐dispersive analytical system consisting of an electron probe analyser and the Harwell ‘Highspec’ pulse analyser system 3074. The use of fast beam switching ( ∼ 30 ns transient time) and the special timing facilities available in the Harwell equipment reduce the spectrum contamination due to displacement of the probe during switching to a low level and also provide precise measurements of live time, essential for accurate analysis. Analyses performed at spectrum accumulation rate of up to 12 kP.P.S. shows agreement with accepted values to within ± 1% for major constituents. Simple modification of the system permits accumulation rates up to 25 kP.P.S.
A self‐consistent calibration method for industrial X‐ray spectrometric analyses
Authors: Tertian R. 
Published: May 2005

AbstractA fast, efficient calibration procedure is proposed based on the accurate analysis of multicomponent systems by means of the influence coefficient method. It relies on a series of well designed additions made to a suitable standard composition, the latter also being used as a reference sample. We show that, for an n element composition, using the hypothesis of constant coefficients, (n + 1) preparations – allowing n(n + 1) intensity measurements – are in principle sufficient to calculate the n2 calibration parameters [i.e. n(n − 1) influence coefficients and n referenc relative intensities] which are necessary for a complete analysis. Actual analyses are carried out by measuring the fluorescent intensities using the ratio (i.e. unknown/standard) method, and then calculating the concentrations from the usual relationships through an iterative calculation, preferably executed by a computer program. A detailed description of a typical application is given, which involved the study of fused specimens (borax fusion) of bauxite and resulted in the very accurate analysis of calcined samples, as well as the direct analysis of raw bauxites following an adequate treatment of the ignition loss problem. While the method is immediately applicable to every system studied in either solid or liquid solution, it clearly extends to compact systems over a suitable compositional range, provided that carefully controlled additions can be achieved and that all prepared samples are homogeneous.
The effect of oxidation state on the intensities of Kβ5 and Kβ″ of 3d‐transition elements
Authors: Asada E. , Takiguchi T. , Suzuki Y. 
Published: May 2005

AbstractUsing a commercially available flat crystal spectrometer in a slightly modified form, an investigation was made of the peak intensity ratios (Kβ5/Kβ1) and the relative intensities of Kβ″ to Kβ5 in different oxidation states of 3d‐transition metal atoms existing in forms of oxidic compounds. The peak intensity ratios (Kβ5/Kβ1) for V, Cr, Mn, Fe, Co, Ni and Cu, as well as the peak profiles of Kβ″ and Kβ5 for V, Cr and Mn, were investigated. Results suggest that changes in the intensities of the Kβ5 and Kβ″ bands can be applied to determining the oxidation number of a metal atom in its oxide.
The generation, absorption and anisotropy of thick‐target bremsstrahlung and implications for quantitative energy dispersive analysis
Authors: Statham Peter J. 
Published: May 2005

AbstractThe bremsstrahlung spectrum from a thick specimen bombarded with 20 ke V electrons is studied with emphasis on the shape rather than the absolute intensity in the energy range 1–10 keV. Monte Carlo calculations are described in detail and used to compare the absorption corrections for characteristic and continuous (bremsstrahlung) radiation from a thick specimen and to determine the extent to which anisotropy modifies the intensity distribution of the continuum. The absorption corrections are found to differ by roughly 5% for f(χ) = 0.5 and 10% for f(χ) = 0.2, but it is shown that the ratio of the corrections can be predicted by using the ratio of two Philibert‐type formulae. Anisotropy has little influence on the absorption correction but changes in atomic number or geometry may result in the intensity distribution being altered by typically 5‐10% across the energy range 1–10keV. Numerical integration gives values for the generated brems‐strahlung intensity which are used in constructing an expression to represent the functional form of the background. Although experimental spectra confirm this to be superior to the combination of Kramers' law and a characteristic absorption expression, several sources of error at low energies, including bremsstrahlung from the Be window, are pointed out and improvements suggested. In order to eliminate the principal uncertainty, that of the overall efficiency curve for a Si(Li) detector and pulse‐processor, it is recommended that a stored spectrum be used as a ‘background standard’ for explicit background corrections. Errors are then reduced to the 0.1% absolute concentration level, which is suitable for quantitative analysis.
The analytical description of the white spectrum from a Mo X‐ray tube
Authors: Castellano E. E. , Rivero B. E. 
Published: May 2005

AbstractKramers' formula for the white intensity distribution from a diffraction X‐ray tube is modified to obtain a better analytical description of the observed values. The correction is performed through the multiplication of an exponential factor which depends upon a conveniently defined ‘effective depth’ of X‐ray white production. This effective depth is obtained for a Mo target as a function of operating voltage (varying from 8.5‐50 kV) and wavelength (varying from 0.421–2.310 Å).
Accuracy, precision and detection limits of energy‐dispersive electron‐microprobe analyses of silicates
Authors: Dunham A. C. , Wilkinson F. C. F. 
Published: May 2005

AbstractThirty analyses of each of nine well‐characterized silicate glasses and minerals have been made, using a Link Systems Model 290‐2KX energy‐dispersive spectrometer, fitted to a Cambridge Geoscan. Statistical analysis of the analytical data shows that the accuracy and precision of energy‐dispersive analyses are comparable to wavelength‐dispersive analyses, provided that more than about 1 wt% of each element of interest is present. The detection limits for different elements vary accrding to the nature of the sample, the element concerned and the counting time. For 100 liveseconds counting times the detection limits are in the range from 0.05–0.26 wt % of elements.
Computer analysis of X‐ray spectra (EDS) from thin biological specimens
Authors: Bauer Richard , Rick Roger 
Published: May 2005

AbstractThe analysis of energy‐dispersive X‐ray spectra in the low energy region is complicated by the fact that the shape of the background curve is distorted by absorption and the characteristic peaks partially overlap. A computer program (FORTRAN) has been developed, which fits to the measured spectrum an artificially generated one, composed of calculated background and peaks. The parameters defining the artificial spectrum are simultaneously adapted. After four to five iterations of that adaptation, good agreement with the measured spectrum is achieved. This procedure takes about 3 min, using a small computer system.
A proposed model for particle‐size effects in the X‐ray fluorescence analysis of heterogeneous powders that includes incidence angle and non‐random packing effects
Authors: Hawthorne Alan R. , Gardner Robin P. 
Published: May 2005

AbstractAn empirical model that includes the effect of incidence and exit angles and non‐random packing effects is proposed for describing the effect of particle size on the measured X‐ray fluorescence (XRF) response from thick heterogeneous samples. An exact model is derived that illustrates these effects for the ideal case of reglarly oriented cubes, and the previous models at high concentrations of a single homogeneous particale the proposed model and the previous models at high concentrations of a single homogeneous particle type where the largest difference between the previous models is observed. It is shown that at specific angles of incidence and exit the proposed model agrees closely with each of the earlier models. Experimental data taken at different incidence angles show that the proposed model provides the best least‐squares fit to the observed data on the basis of the minimum reduced chi‐square value.
An X‐ray fluorescence method for coating thickness measurement
Authors: Jain S. K. , Gupta P. P. , Eapen A. C. 
Published: May 2005

AbstractAn X‐ray fluorescence method for the measurement of film and coating thickness has been described for use in situations where standard foils of the same material are not available for comparison. The method is based on the measurement of combined mass absorption coefficient of the coating element at the excitation and at the fluorescent energies using thin samples of a compound in which the coating element is present and then calculating the coating thickness using the fluorescence equation. The paper describes the theoretical approach and presents the result of the measurement of certain film and coating thicknesses which support the theoretical considerations.
Deconvolution of energy‐dispersive X‐ray peaks using the poisson probability function
Authors: Ingamells C. O. , Fox J. J. 
Published: May 2005

AbstractA disability of energy‐dispersive X‐ray (EDX) analyzers is the relatively poor resolution of available detectors. Much work has been done in efforts to separate overlapping peaks. It is recognized that the distribution of signals registered in the several channels around a peak is essentially Poisson, but most efforts at deconvolution have been based on Gaussian statistics, probably because of difficulties encountered in the use of the Poisson formula. These difficulties have been overcome, and a simple method for deconvoluting two, three or more overlapping peaks in an EDX spectrum has been developed.
Comparison between experimental and calculated relative escape peak intensities for an intrinsic Ge detector in the energy region 11–25 keV
Authors: Christensen L. H. 
Published: May 2005

AbstractExperimental measurements of the relative intensity of the escape peak produced in an intrinsic Ge detector agree quite well with the calculated intensities based on a theoretical model. Contrary to the Si(Li) detector Kα as well as Kβ escape peaks are observed. In the energy region 11–25 keV the Ge Kα escape peak intensities vary from 16.3 to 4.7% and the Ge Kβ escape peak from 2.4 to 0.9% of that to the parent line. Therefore, the escape peaks are not negligible in X‐ray fluorescence analysis, and it may be necessary to numerically correct for them or, by a suitable choice of excitation energy, avoid them completely.
The suitability of energy‐dispersive electron‐microprobe analysis for the investigation of stainless steels
Authors: Dunham A. C. , Wilkinson F. C. F. 
Published: May 2005

AbstractCarefully polished samples of five austenitic stainless steels have been examined by reflected light microscopy and analysed, using a Link Systems model 290 KX energy‐dispersive spectrometer attached to a Cambridge Instrument Company Geoscan microprobe. At least ten different spots within apparently homogeneous areas of each sample were analysed. While the means of these analyses agree well with the published values, three of the samples have an inhomogeneous distribution of their major elements. Precipitates within the samples are mainly MnCr2O4 and MnS, both with much substitution of the Mn by other elements. Other precipitates are rich in P or Nb. While such blocks are probably sufficiently homogeneous for use as bulk standards, great care should be exercised if they are to be used as microprobe standards. A small excess of silicon was found in most analyses. This is believed to be due to fluorescent excitation of silicon in the detector. Analyses of pure metals suggest that a correction of 0.12 wt % silicon should be applied.
Zur quantitativen mikrosondenanalyse von geologischen proben mittels kombiniertem EDS/WDS
Authors: Schwander H. , Gloor F. 
Published: May 2005

AbstractEs wird eine quantitative Analysenmethode für geologische Proben (Silikate and Karbonate) mittels Röntgenmikrosonde beschrieben. Im Falle von Silikaten sind fur eine Totalanalyse mehr als 10 chemische Elemente simultan zu erfassen (Haupt‐und Nebenelemente). Zwei experimentelle Moglichkeiten sind realisierbar: (a) Automatischer Sequenzbetrieb mittels Kristallspekrometern; (b) Kombination WDS/EDS (wellenlangendispersives und energiedispersives System). Diese beiden Möglichkeiten werden diskutiert. Technische Angaben und apparativer Aufwand werden beschrieben. Es wird dargelegt, auf welche Weise eine hohe analytische Genauigkeit erreicht werden kann.
Energy‐dispersive XRF spectrometry using secondary radiation in a cartesian geometry
Authors: Bisgård K. Maack , Laursen J. , Nielsen B. Schmidt 
Published: May 2005

AbstractThe design of an energy‐dispersive spectrometer equipped with a conventional X‐ray tube and a secondary target is described. The mechanical construction secures a well defined geometry and a high degree of flexibility. The geometry of the irradiation chamber has allowed the polarizing effect of scattering to be investigated. With emphasis on analysis of infinitely thick biological samples a close approximation to the fundamental parameter method for matrix correction has been studied.
Quantitative X‐ray diffraction analysis with qualitative control of calibration samples
Authors: Knudsen Torben 
Published: May 2005

AbstractSamples containing identical or very similar phases and differing in their contents of these can be used for calibration of a quantitative X‐ray diffraction analysis without knowing their actual mineralogical composition. The method requires that at least one major peak for each phase is well isolated and that the number of calibration samples is equal to or exceeds the number of phases.
Calibration of tube excited energy‐dispersive X‐ray spectrometers with thin film standards and with fundamental constants
Authors: Van Espen P. , Adams F. 
Published: May 2005

AbstractThe calibration of an energy‐dispersive X‐ray spectrometer is calculated from published physical constants, when the geometry factor of secondary target, sample, detector is obtained experimentally and when the detection efficiency of the Si(Li) detector is calculated from such experimentally derived parameters as the thickness of cryostat window, gold surface barrier contact and silicon dead layer. The results are compared with calibrations obtained experimentally from commercial single element thin film standards obtained by vacuum evaporation and multielement standards obtained by incorporating known amounts of the elements into a thin film polymer. The results obtained from fundamental parameters agree with the experimental data to within 5–6%.
Window contamination of energy‐dispersive detectors in electron microprobe analysis
Authors: Smith D. G. W. 
Published: May 2005

AbstractOil film contamination of the Be window of a Si detector has been demonstrated using archival information on X‐ray intensities from calibration standards acquired over a two and a half year period. Although cleaning the window with a solvent restores sensitivity for soft radiation, recontamination can be rapid unless a small heating device is placed close to the window. A mathematical correction is suggested which avoids significant analytical errors from the effect of any contamination which may be present. It can be applied automatically by data processing software using information from the calibration standard spectrum.
The calculation of background in wavelength‐dispersive electron microprobe analysis
Authors: Smith D. G. W. , Reed S. J. B. 
Published: May 2005

AbstractA procedure has been developed for the calculation of background corrections in wavelength‐dispersive electron microprobe analysis which reduces data acquisition times and offers the possibility of greater accuracy and lower detection limits, especially when the number of peaks concerned is large. An empirical ‘normalized background’ in conjunction with a modified version of Kramers' law (as developed for energy‐dispersive analysis) is used to calculate continuum intensity, enabling the background to be estimated for any wavelength from a single measured value. This approach is compatible with modern trends towards automation of data acquisition and processing.
Evaluation of dead‐time corrections in EDS systems
Authors: Bloomfield D. J. , Love G. , Scott V. D. 
Published: May 2005

AbstractTwo common methods of applying dead‐time corrections in EDS systems, both of which are carried out internally in the electronics, are examined. The Barnhart method shows serious discrepancies when making dead‐time corrections and in certain cases no correction is made at all. The problem is associated with the reliance on the fast amplifier to count all x‐rays collected by the detector. In practice, however, the fast amplifier does not always succeed in carrying out this function since x‐rays with energies < 1500 eV may fall below its threshold level. The problems become worse when a formvar window is substituted for beryllium since a greater proportion of low energy x‐rays can now reach the detector. The magnitude of the discrepancy is shown also to be a function of specimen and electron accelerating voltage. Similar experiments with an EDS system using the Covell method show that no such discrepancies arise.
Real time chemical analysis of phosphoric acid using energy dispersive x‐ray fluorescence
Authors: Marvin Dean C. , Ives Neil A. 
Published: May 2005

AbstractEnergy dispersive x‐ray fluorescence is shown to be an effective analytical method for determination of calcium, sulfur and phosphorous concentrations in wet process phosphoric acid. Periodic monitoring of these quantities is essential to plant operation, and is presently carried out using separate wet chemical analyses. The XRF method described here has the advantages of increased speed, of multi‐element determinations from a single measurement, and of having the potential for on‐line use in an automatic plant control loop.