bluuebunny/crossref_metadata_2025_split huggingface dataset:
Runaways in X‐ray spectrometry
Authors: Plesch R. 
Published: May 2005

AbstractA runaway criterion is proposed for X‐ray spectrometry which is based on the standard deviations obtained from the standard specimens with and without the analysis value to be tested. The standard deviations which are printed out on modern equipment are compared by means of the F test. The procedure is explained by means of examples. The consequences for the analysis of unknown specimens are discussed.
A versatile, compact system for X‐ray fluorescence analysis
Authors: Ricci Enzo , Dunn H. W. 
Published: May 2005

AbstractWe have developed a highly versatile, energy‐dispersive system for X‐ray fluorescence (XRF) analysis. Excitation may be achieved both by a Ag anode tube and by isotopic sources of 241Am or 55Fe. Radiation from the former may be either filtered and collimated, or monochromatized by a pyrolytic graphite cylindrical monochromator with further filtration through Pd foils. The system is currently being used both for quantitative fundamental‐parameter (absolute) analysis and for standard‐based determinations. A variety of mounts allows quantitative work on solid thick or thin samples, liquids, and specimens evaporated on 6.2 μm thick Mylar. Aside from single‐sample operation, a 90 position sample changer allows multi‐sample analysis, with great gain in work efficiency. The latter is automatically controlled by a PDP 11/05 computer, which also calculates results from the raw data from a Tracor Northern NS 880 energy‐dispersive system. Accuracies for analyses of steels (percent level) are ∼5%, while trace Zr/Hf analysis can be performed with 10–15% error; sensitivity for the latter is 0.4–1.0 ppm.
X‐Ray K absorption edge studies of cobalt in complexes with nitrogen based aromatic ligands
Authors: Kumar A. , Nigam A. N. , Srivastava B. D. 
Published: May 2005

AbstractThe X‐ray K absorption edges of cobalt in some complexes with nitrogen based ligands [α‐Co(py)2Cl2, Co(py)2Br2, Co(bipy)Br2 and Co(phen)Br2] have been recorded using a 40 cm bent crystal spectrogrph. The absorption edge shift and edge width have been discussed in terms of effective nuclear charge, molecular symmetry and the nature of the ligand. The radii of the first coordination sphere have been calculated using Levy's method and a correlation suggested.
An evaluation of X‐ray tube spectra for quantitative X‐ray fluorescence analysis
Authors: Murata Michihiro , Shibahara Hiroyasu 
Published: May 2005

AbstractFull spectra including both the continuous and characteristic lines from X‐ray tubes are evaluated in a simple way. The penetrating depth of an electron in the target of the X‐ray tube is determined and the Kramers' spectrum corrected for the effects of absorption. The characteristic lines are evaluated from a relation between direct electron excitation and indirect excitation by continuous X‐rays. The calculated spectra from W and Cu X‐ray tubes are given and their usefulness is confirmed by analysing some typical samples including Ag/Pd and Cu/Zn alloys and BaO/TiO2 mixed oxides.
Automatic qualitative identification of unexpected elements in quantitative energy‐dispersive X‐ray spectrometry
Authors: Leyden D. F. , Bodnar W. B. , Lemons W. 
Published: May 2005

AbstractA combination of deconvolution, spectra subtraction and elemental identification routimes has been made to alert the energy‐dispersive X‐ray spectrometrist to elements present in the sample but not included in the fit.
Comparison of the Japanese industrial standard and α‐correction methods for X‐ray fluorescence analysis of steels
Authors: Ito Minao , Sato Shoki , Narita Masanao 
Published: May 2005

AbstractIn the X‐ray fluorescence analysis of steels, a correction method is usually used to eliminate absorption‐enhancement effects. It is a desirable that the correction factors should be common to all experimental conditions and therefore the fluorescent X‐ray intensity should be specified in a common unit. For this purpose, the JIS method converts the fluorescent X‐ray intensity into a tentative analytical value from the calibration curve of binary alloys, while the α‐correction methods employs the ratio of the intensity of an analytical sample to that of a pure substance for the fluorescent X‐ray intensity. In this report a detailed comparison of these methods is made, and the good and bad points of the JIS method discussed.
A computer program to evaluate a counting loss correction constant in XRF analysis
Authors: Stecher Ole 
Published: May 2005

AbstractDifferent sources of counting loss are described and the relation Rt = Rm exp (Rt τ) is considered valid for most commercial XRF counting devices. Based on a series of Kα/Kβ measurements and an initial estimate of the Rt (Kα)/Rt (Kβ) value, corresponding τ values can be computed. If the chosen Rt (Kα)/Rt (Kβ) value differs from the correct one, the τ values will not be identical. The computer program iterates the Rt (Kα)/Rt (Kβ) value until the τ values have reached a desired level of agreement. The program is given together with a worked example of the calculation.
Analyse Automatique des Spectres de Rayons‐X par Dépouillement Spectral
Authors: Lecomte R. , Landsberger S. , Paradis P. , Monaro S. , Desaulniers G. 
Published: May 2005

AbstractUne méthode complétement automatisée de dépouillement des spectres de rayons‐X ne faisant appel à aucune description analytique de la forme des pics et du bruit de fond, est adaptée à l'analyse de la région à basse énergie du spectre. La décomposition du spectre d'un échantillon en ses composantes indépendantes est réalisée à l'aide d'une librairie compléte de spectres standards incluant un bruit de fond témoin. Le principe de calcul suggéré permet de tenir compte des sources de contamination des échantillons de facon simple et originale.
Fast X‐ray imaging using a position sensitive proportional counter
Authors: Gurker N. , Zeiner K. 
Published: May 2005

AbstractAn X‐ray imaging method based on image reconstruction from projections has been established by analogy to medical computed tomography (CT). Where CT uses transmission, X‐ray imaging (X‐ray macroscopy, XMA) uses reflection. Using an energy‐dispersive Si(Li) detector and performing translation and rotation steps of the sample across the line focused X‐ray beam separately and sequentially, X‐ray imaging suffers from long data acquisition times (several hours). A position sensitive proportional counter (PSPC) has been used to generate a complete translation profile (projection) simultaneously. The sample is illuminated by an X‐ray cone and the reflected fluorescence intensity distribution imaged on to the PSPC by an imaging slit. Scanning movements are reduced to sample rotations; sample translation is not required. Preliminary experiments have shown that data acquisition times are shortened by a factor of ten. An experimental arrangement for fast tomographic imaging, results and some problems arising from using a PSPC are discussed. Finally, a second direct imaging experiment, equivalent to scanning the sample across a point‐focused X‐ray beam, is introduced.
Direct determination of trace elements in coal: Wavelength‐dispersive X‐ray spectrometry with matrix correction using compton scattered radiation
Authors: Mills John C. , Turner K. E. , Roller P. W. , Belcher C. B. 
Published: May 2005

AbstractAn X‐ray flourescence method is described for the direct determination, without pretreatment, of up to 55 trace elements in coal and coal‐derived materials. A single assay specimen is prepared by blending finely crushed sample with a binder and briquetting. Calibration is effected by a suite of synthetic calibration standards prepared from spectrographically pure materials blended into graphite. Variations in ash and sulphur content required matrix absorption corrections to analyte and background intensities, which were achieved by use of relationships with the measured Compton scattered radiation. Prior knowledge of or assumptions concerning the composition of the coal are not required. Accurate results are presented for three NBS coal standard reference materials. Certain elements (including TI, Hg, Te, In, Cd, Ag and most rare earths) are normally present in coal at levels below the detection capability of the described method and require quantification by alternative techniques.
The application of energy‐dispersive X‐ray fluorescence and the fundamental parameter approach to the analysis of NiFeCr alloys
Authors: Christensen Leif Højslet , Pind Niels 
Published: May 2005

AbstractThe fundamental parameter approach has been applied to NiFeCr alloys using an energy‐dispersive X‐ray fluorescence spectrometer employing secondary target excitation. The relative distributions of primary, secondary and tertiary fluorescence for these alloys and some of the assumptions inherent in the fundamental parameter approach are discussed both on a theoretical and an experimental basis. For a series of hypothetical NiFeCr alloys, our theoretical calculations show that the tertiary fluorescence contribution to the Cr intensity varies from 0.1 to 7.25% dependent on composition and on excitation energy. Furthermore, a general calibration procedure independent of the sample matrix and the kV, mA and collimator settings is outlined. The analysis results obtained for six reference alloys proved to be accurate within 5% for most elements. The results obtained with and without tertiary fluorescence included in the model deviate 2–5% only. This is partly due to a matrix absorption correction compensation in the latter case.
Maximum a posteriori technique applied to energy‐dispersive X‐ray fluorescence spectra
Authors: Schwalbe L. A. , Trussell H. J. 
Published: May 2005

AbstractWe review the maximum a posteriori formalism and apply the technique to the deconvolution problem of energy‐dispsersive X‐ray fluorescence spectra. An exact closed‐from expression for the a priori probability density is derived from physical considerations. A single CuZn spectrum is taken to illustrate the effects of various assumed forms for the restored spectrum probability distributions. Our best results follow from calculations that involve a self‐consistency condition. These restorations are contained within the set of maximum likelihood solutions.
Comparison of different methods for the matrix correction in X‐ray spectrometry
Authors: Plesch R. 
Published: May 2005

AbstractIn order to empirically test five mathematical equations of matrix correction, the theoretical X‐ray intensities of the ternary system CrFeNi were used. The smallest analysis error was obtained from a complicated equation which was derived from theory. Simplification of this equation resulted in the equation developed by Rasberry and Heinrich which proved to be almost as effective and is thus to be preferred in practice because of its simpler structure. A further simplification, dispensing with a special correction for secondary fluorescence, led to a greatly increased analysis error. As expected, using the matrix element intensities instead of their concentrations resulted in larger analysis errors. Special consideration of the secondary fluorescence did not yield a better result. These results agree qualitatively well with the results obtained by Stankiewicz and Sanner which were obtained by means of the analysis of synthetic oxide standards.
Double line Bragg reflection technique in energy dispersive X‐ray diffractometry
Authors: Mantler M. 
Published: May 2005

AbstractThe double line Bragg reflection technique allows phase transition studies with a time resolution of 0.2 s. The Kα and Kβ emission lines from the X‐ray tube are recorded simultaneously in an energy‐dispersive detector system. Both lines satisfy Bragg's equation for a different phase in the specimen. The latitude of parameter variations and the probability for the required parameter match are discussed on the basis of a specimen transparency model.
Energy dispersive x‐ray diffractometry: 2. Phase transformations at elevated temperatures
Authors: Mantler M. 
Published: May 2005

AbstractPhase transformation studies as well as the determination of linear expansion coefficients are used to show characteristics, accuracy and methods of data evaluation in energy dispersive x‐ray diffractometry. A high temperature chamber was modified to withstand temperatures up to 2300°C with fixed angle geometry. Observation of phase transformations in time frames of 10s was possible. In addition, error analyses are made and a method of comparing intensities from angular dispersion to energy dispersive lines is presented.
Rapid preparation of robust pressed powder briquettes containing a styrene and wax mixture as binder
Authors: van Zyl C. 
Published: May 2005

AbstractThe binder is composed of nine parts (by mass) styrene copolymer and one part wax. Both ingredients are marketed under brand names and are available as 10 μm powders, which can be conveniently blended in bulk. Exceptionally robust briquettes containing 10% binder have been made from a great variety of sample types, including metal powders, ion exchange resins, coal, charcoal, graphite, ash, vegetable matter and geological materials. Normally the sample and binder are milled together in a swing mill and milling behaviour is not adversely affected. The briquettes are not affected by vacuum, radiation or age. Erratic milling efficiency of the six‐vessel swing mills used and modifications to overcome the problem are described. For the most satisfactory ejection of a briquette, the cylinder wall of the die should taper slightly outwards near the ejecting end. A pressure of at least 0.04 MPa is recommended to ensure maximum x‐ray fluorescence intensity, but higher pressures improve briquette strength. In the above‐mentioned laboratory 0.23 MPa is normally used. The time the briquette is held under full load is not important. The simplicity of the method makes it possible to mill and press more than 1000 briquettes per day. Binder cost is approximately 3 cents per gram.
A comparison of two equations used as calibration curves for ternary samples in x‐ray fluorescence spectrometry
Authors: Mainardi R. T. , Rubio M. , Meda J. 
Published: May 2005

AbstractIt is well known that calibration curves in x‐ray fluorescence spectrometry offer to the analyst different alternatives to fit measured data. We have set out to compare two well‐known algorithms, those of Rasberry and Heinrich (R–H) and Lachance and Traill modified by Claisse and Quintin (LTCQ), with computer generated data using the fundamental parameter method. It is seen that both work reasonable well for binary samples, but in ternary samples deviations from reference points are larger for R–H than for LTCQ. We conclude from this study that ternary effects in R–H are not accounted for adequately, since only binary coefficients are needed to determine a calibration curve for any ternary as well as any multicomponent sample. In LTCQ, inclusion of an additional coefficient determined from a ternary standard suffices to improve considerably the degree of fitting to reference.
Energies et Probabilités de Transition des Raies XL du Neptunium
Authors: Maria H. , Dalmasso J. , Ardisson G. , Hachem A. 
Published: May 2005

AbstractLe spectre xL du Np accompagnant la désintégration de 241Am a été soigneusement examiné avec des détecteurs HPGe. Les valeurs des énergies des raies principales sont en bon accord avec les résultats déduits du travail de Bearden, sauf pour les raies Lα1 et Lβ2,15 qui dépassent les valeurs théoriques de 8 et 22 eV respectivement. Les intensités des différentes raies s'accordent bien avec les résultats antérieurs; les raies β9, β10, γ11, γ13, t et s sont caractérisées pour la première fois dans le Np (Z = 93). Les rapports de probabilité dans les sous‐couches L sont cohérents avec les calculs Hartree–Fock–Slater de Scofield.
X‐ray fluorescence analysis of natural phosphates
Authors: Waňková J. , Knob B. , Moudrý F. , Kuba M. 
Published: May 2005

AbstractAn x‐ray fluorescence method was developed for the determination of P and Ca in raw phosphates. A modified mathematical method suggested by Lucas‐Tooth and Pyne was used to correct for matrix effects. The constants and influence coefficients in the algorithm were assessed using a set of 20 standard samples whose composition was determined by chemical analysis. The correspondence of P and Ca concentrations, as determined by the x‐ray method in samples from different deposits all over the world, with the results of chemical analysis can be characterized by the coefficient of variation v of the differences between the two methods. The value of v was 1.2% and 1.8% for P and Ca, respectively. The effects of a preliminary treatment of phosphates by calcination and of reducing the number of phosphate rock deposits, the samples of which are analysed, on the value of v are discussed.
Minimum flux fusion processing of iron ores for XRF analysis
Authors: Feret F. 
Published: May 2005

AbstractThe effects of particles size, sample‐to‐flux ratio, fusion temperature and fusion period on the speed of lattice decomposition of three different iron ores were tested. Russian Krivoj Rog (hematite), Jugok concentrate (magnetite) and Polish siderite were used for structural investigations. In order to estimate the degree of crystallographic destruction of the material, x‐ray diffractometry was used. Contrary to the usual large dilution associated with fusion, experiments with minimum flux contribution were carried out. The heat treatment (fusion) of samples was performed in graphite crucibles. The minimum flux technique was compared with dilution fusion (Pt‐Au crucibles) on 32 iron ore standards.
Self‐absorption of As, Se and Br for their Kβ2 and Kβ1,3 radiations and its effect on intensity ratio measurements (chemical state analyses of As, Se and Br by X‐Ray Method. 3)
Authors: Iwatsuki Masaaki , Fukasawa Tsutomu 
Published: May 2005

AbstractA dependence of the observed Kβ2/Kβ1,3 intensity ratios of As, Se and Br on their concentrations in measured samples was found in a study of the use of these ratios in chemical state analysis. This paper includes the experiments and discussion on this concentration effect, which is caused by the large difference between the self‐absorption coefficients of each element for its Kβ2 and Kβ1,3 radiations. An x‐ray spectrometer was used for the measurements of the intensity ratios and absorption coefficients. Since the Kβ2 radiation of each element has a wavelength shorter than the Kβ1,3 radiation and longer than the K absorption edge, the self‐adsorption coefficient of the Kβ2 radiation was presupposed to be smaller than that of the Kβ1,3 radiation. The results of experiments, however, were contrary to the supposition. The observed self‐absorption coefficients of these elements for their Kβ2 radiations were 1.4–2.2 times those of their Kβ1,3 radiations, depending on the chemical states of the elements as absorbers or x‐ray emitters. These values gave a solution to the concentration effect. The correction of the effect allows the inherent intensity ratios to be determined which may then be used for chemical state analysis.
A semi‐empirical method for quantitative XRF analysis of thick samples
Authors: Govil R. , Kataria S. K. 
Published: May 2005

AbstractA simple semi‐empirical procedure for the determination of elemental concentration in light element matrices is proposed. The method consists of taking x‐ray fluorescence spectral measurements at several orientations of the thick planar samples with a standard x‐ray fluorescence set‐up consisting of a low power x‐ray tube and a Si(Li) x‐ray spectrometer. The measured intensities are then extrapolated to zero effective thickness for the fluorescent x‐rays. In the following we have carried out the extrapolation procedure for the ratios of the Compton scattered Mo Kα x‐rays to the fluorescent x‐rays which provides the direct determination of the elements in p.p.m. units with respect to the light matrix.
The Cu Kα1,2 spectrum as measured with a curved‐crystal spectrometer
Authors: Bremer J. , Johnsen T. , Sørum H. 
Published: May 2005

AbstractAn experimental study of the fine structure of the electron excited Cu Kα1,2 doublet in the energy range 20‐40 ke V is presented. The spectra are different from earlier published ones in the sense that both the intensity and the resolution are high. A convex‐crystal setting of the spectrometer is discussed. It is pointed out that when using a point source in association with a convex crystal the broadening due to the curvature of the planes vanishes. The high intensity enables one to unambigiously introduce two Lorentzians. The characteristic profile and location of the difference between the experimental data points and the fits show that the asymmetry of the Cu Ka1 and Kα2 lines most probably is due to the radiative Auger mechanism K‐LM.
A formed filter paper medium for microdroplet analyses of liquid samples by X‐ray fluorescence spectrometry
Authors: Murata Michihiro , Murokado Kenichi 
Published: May 2005

AbstractA new type of a formed filter paper is proposed as a sample medium for a microdroplet analysis by x‐ray fluorescence spectrometry. It has a circular center part, separated by a narrow circular groove from its edge, and four, paraffined, supporting bridges. It can thus keep a spot area constant when a liquid sample drops at the center part. After dropping the liquid sample, the paper is dried and used for the x‐ray measurement. It can be stored for years without any chemical change. This formed filter paper is effective in improving the linearity range of a calibration curve and the precision of a fluorescent x‐ray measurement as compared with a non‐formed filter paper. The sample volume required is only 20 to 100 μ1 and therefore microscale analysis of the liquid sample is allowable.
Sample analysis using gamma ray induced fluorescent x‐ray emission
Authors: Sood B. S. , Allawadhi K. L. , Gandhi R. , Batra O. P. , Singh N. 
Published: May 2005

AbstractA non‐destructive method for the analysis of materials using gamma ray‐induced fluorescent x‐ray emission has been developed. In this method, special preparation of very thin samples in which the absorption of the incident gamma rays and the emitted fluorescent x‐rays is negligible, is not needed, and the absorption correction is determined experimentally. A suitable choice of the incident gamma ray energies is made to minimise enhancement effects through selective photoionization of the elements in the sample. The method is applied to the analysis of a typical sample of the soldering material using 279 keV and 59.5 keV gamma rays from 203Hg and 241Am radioactive sources respectively. The results of the analysis are found to agree well with those obtained from the chemical analysis.
The estimated binary calibration curve method in the JIS x‐ray fluorescence analysis of steels and standard samples necessary for the method
Authors: Ito M. , Sato S. , Narita M. 
Published: May 2005

AbstractIn the Japanese Industrial Standard for the x‐ray fluorescence analysis of steels, the ‘estimated binary calibration curve’ method has been adopted. In this method, the calibration curve for the binary system, consisting of an analyte and the principal constituent elements is estimated and derived by using multicomponent standard samples. The measured x‐ray intensity is first converted into a tentative analytical value from this calibration curve, and then the analytical result is derived from this tentative value using the correction procedure. In this paper, some methods and standard samples of making the estimated binary calibration curve are compared and discussed, also, the characteristics of the JIS method are described.