bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of trace elements in hair of pregnant women using XRF spectrometry
Authors: Tomić S. , Lakatoš J. , Valković V. 
Published: May 2005

AbstractIt was shown that x‐ray fluorescence is very suitable for following changes in trace element concentrations in the hair of pregnant women. Two hundred hair samples were analysed, mean concentrations for Cr, Mn, Fe, Cu and Zn were evaluated quarterly and their distribution according to weeks of pregnancy was determined. Possibilities of using longitudinal hair analysis with the purpose of following the concentrations of some particular microelements in the course of pregnancy are discussed.
EDXRF and XRD studies on alumina fibre using natural fibre as substrate
Authors: Patel M. , Padhi B. K. , Sastry D. L. 
Published: May 2005

AbstractThe structural characterization of alumina fibres obtained from an aluminium salt and three natural fibres (jute, sisal and coir) was examined by EDXRF and XRD. Elemental composition spectra from EDXRF of fibres pyrolysed at 1200 and 1400°C are presented and the results are compared with those obtained by wet chemical analysis and atomic absorption spectrometry. XRD diffractograms of the same samples are also shown. The evolution of the α phase of alumina with increase in pyrolysis temperature was examined. Scanning electron micrographs of alumina fibre with jute fibre are also presented.
Recent results using synchrotron radiation for energy‐dispersive x‐ray fluorescence analysis
Authors: Jaklevic J. M. , Giauque R. D. , Thompson A. C. 
Published: May 2005

AbstractResults obtained using synchrotron radiation as an excitation source for energy‐dispersive analysis are reviewed. Practical experience gained in the use of tunable, monochromatic excitation for trace analysis of various types of samples is discussed. Advantages and limitations associated with specific synchrotron radiation properties are evaluated. In particular, the influence of multiple inelastic scattering and resonant Raman scattering on limiting the degree of detectability improvements associated with energy tuning is demonstrated. A scanning x‐ray microprobe employing multilayer mirrors as focusing elements is described. Measurements performed with this system have demonstrated the capability of detecting femtogram quantities of trace elements in a 10 × 10 μm area.
XRS analysis of sulphides by fusion methods
Authors: Norrish K. , Thompson G. M. 
Published: May 2005

AbstractA method is described for the XRS fusion analysis of mineral and plant concentrates containing sulphides (e.g. PbS, ZnS, CuFeS2 and FeS2) together with slags, mattes, fumes and drosses. The method involves a short pre‐oxidation treatment using sodium nitrate, followed by fusion with an appropriate heat source. Losses of S by volatilization and of metals into the platinum crucibles are acceptably small for general assay purposes.
Coordination state research in glasses by XRF
Authors: Xiaoding Li 
Published: May 2005

AbstractAl and Zn coordination states in several kinds of glasses were measured with a common x‐ray fluorescence spectrometer. The results showed that the Al in P2O5‐Na2O‐BaO‐Al2O3 phosphate glass is all sixfold coordinated, the Al in alkaline silicate glass is fourfold coordinated and the Zn in Na2O‐ZnO‐B2O3 glass system is all fourfold coordinated, the results being in agreement with those given by EXAFS. It is concluded that the study of the coordination states of complex glass systems is an effective method.
Line identification and other simple wavelength‐dispersive x‐ray spectrometric calculations using a pocket calculator
Authors: Török I. 
Published: May 2005

AbstractAn HP‐11C (‐15C) program set, which performs conversions between quantities used in wavelength‐dispersive x‐ray spectrometry, e.g. wavelength, energy, Bragg angle and energy‐resolving power, is described. Any advanced programmable pocket calculator with continuous memory can be used instead of spectrometer tables.
Apparatus for low‐energy X‐ray fluorescence using an Al K X‐ray source and an Si(Li) detector
Authors: Musket R. G. , Holmes S. J. 
Published: May 2005

AbstractThe concept, design, characterization and operation of an apparatus for low‐energy x‐ray fluorescence are described. This system utilizes commercially available components in a novel arrangement. An Al K x‐ray source, an ultra‐thin‐windowed Si(Li) detector and an ion gun for sputter cleaning were combined to perform analyses for elements with atomic number Z ⩾ 6. Pairs of slit collimators placed between the specimen and the x‐ray detector defined the area analyzed. The system configuration permitted analyses over areas with a variety of dimensions (0.4–22 mm). Distinction between surface and bulk signals was possible using the sputter‐cleaning capability.
X‐ray fluorescence analysis for oxygen on and in materials
Authors: Musket R. G. 
Published: May 2005

AbstractQuantitative analysis for oxygen on the surface and in the bulk of materials has been demonstrated using an energy‐dispersive x‐ray fluorescence system. The system consists of an Al K x‐ray source, an ultra‐thin‐windowed Si(Li) detector and an ion gun for sputter cleaning. Sputter cleaning was required to distinguish between surface and bulk O K x‐ray signals. Since beryllium has one of the lowest mass absorption coefficients for O K x‐rays, calculations and extensive measurements were made for oxygen on and in beryllium. The 3‐α detection limits were 0.22 nm of BeO on beryllium and 98 atomic parts per million (appm) of oxygen in beryllium. Measurements of surface oxides on other materials indicated detection limits of 1.9 nm of SiO2 on silicon and 2.0 nm of Ta2O5 on tantalum. The corresponding detection limits for oxygen in silicon and tantalum were 0.39 and 4.3 at.‐%, respectively.
Rapid analysis of coal fly ash by x‐ray fluorescence spectrometry
Authors: Bettinelli M. , Taina P. 
Published: May 2005

AbstractHigh‐quality data for major elements (Si, Al, Fe, Ca, Mg, Ti, Na and K) and trace elements (Ba, Mn, Cr, V, Cu, Zn, Sr, Ni, Co, As and Rb) can be rapidly obtained by automated x‐ray fluorescence analysis of pressed coal fly ash pellets. The sample preparation procedure does not require supervision and the analysis of a fly ash pellet for 24 elements requires about 45 min of machine time. The basic idea is to use a large number of reference samples with very different compositions (some international coal fly ash standards and fly ash samples analysed by neutron activation analysis and by inductively coupled plasma atomic emission spectrometry) for calculation of the calibration line. The major element precisions are better than 1% of the amount determined and the trace element precisions are generally better than 10%. Limits of determination for many trace elements are in the range 5‐10 μg g−1.
A matrix effect correction algorithm for x‐ray fluorescence analysis of steel
Authors: Gunicheva T. N. , Finkelshtein A. L. , Afonin V. P. 
Published: May 2005

AbstractPolynomial expressions for use as an approximation of the dependence of x‐ray fluorescence intensities on the entire composition of the sample are suggested for correcting for matrix effects in systems such as steels and alloys where the variations of these effects are large. They yield accurate results, and use the fundamental influence coefficients calculated by equations containing fundamental parameters which are determined by the simplest local splines. The essential difference in these fundamental influence coefficients is that they are not connected with the sample chemical composition after the determination and are simulated for maximum possible variations of interfering element concentrations in the matrix. Results for the compositions of some NBS steel standards calculated from published x‐ray fluorescence intensities and the results of analyses of stainless steels are discussed.
Thin‐film characterization by x‐ray fluorescence
Authors: Huang T. C. 
Published: May 2005

AbstractA precise and practical x‐ray fluorescence technique using the fundamental‐parameter method and the LAMA computer program for the simultaneous determination of composition and thickness of single‐ and multiple‐layer thin films is reviewed. Results from the analysis of Fe–Ni single‐layer and chromium, Fe–Ni, copper triple‐layer thin films are discussed. The analysis showed that x‐ray absorption and enhancement caused by the inter‐element effect in single‐layer and the inter‐layer effect in multiple‐layer films were corrected properly. The accuracy of the analysis is estimated to be ±1% for composition and ±3% for thickness.
Calculation of depth distribution functions for characteristic x‐radiation using an electron scattering model. II—results
Authors: August Hans‐Jürgen , Wernisch Johann 
Published: May 2005

AbstractResults obtained from the model of multiple electron reflection are compared with experimental data and values calculated using analytical expressions commonly used in electron probe microanalysis. It is shown that the proposed model quantifies the total amount of generated x‐ray intensity very accurately, the root mean square error obtained from comparison with Pouchou and Pichoir's results being 2.33%. The shape of the depth distribution functions is also predicted very well, as is illustrated by a comprehensive comparison with measured data and with curves obtained from the expressions of Bastin and Heijligers and of Pouchou and Pichoir. Characteristics of the calculated curves and experimental errors affecting the shape of measured depth distribution functions are discussed.
Dependence of XRF intensity on the tilt of the propagation plane: Experimental
Authors: Fernández Jorge E. , Rubio Marcelo , Sánchez Héctor J. 
Published: May 2005

AbstractThe geometrical properties of the x‐ray fluorescence (XRF) intensity related to the α‐parameterization were confirmed experimentally. A special sample stage was built to allow the rotation of the sample with the propagation plane (the plane defined by the incident and take‐off beam directions) and was coupled to an energy‐dispersive spectrometer. The device and the way in which it was carefully aligned with the collimated x‐ray beams are described. The fluorescence spectra of three NBS standard samples were measured for 16 different positions of the α angle. The incident and take‐off angles were both 45° for sample rotations between α = 0 and the maximum angle of 86°. XRF intensities from non‐enhanced lines do not show any dependence on α as predicted by theory. Enhanced lines, on the contrary, decrease in intensity when α increases, allowing the isolation of the primary emission by extrapolation to the limiting case α = π/2.
Energy‐dispersive x‐ray fluorescence analysis of geological materials in borax beads using Tertian's binary coefficient approach combined with internal standard addition
Authors: Muia L. M. , Van Grieken R. 
Published: May 2005

AbstractA rapid procedure for the energy‐dispersive x‐ray fluorescence analysis of geological materials in borax glass beads for Al2O3, SiO2, CaO, TiO2, MnO and Fe2O3 is presented. The method involves the addition of an internal standard, ZnO, to obtain approximate concentrations for the desired element oxides. Refined concentrations are then obtained through corrections for matrix and third‐element effects from theoretically calculated binary influence coefficients and third‐element correction factors using the binary coefficient approach combined with Tertian's correction algorithm. Data are presented for the determination of these major oxides in six Sedimentary Rock Reference Materials. A reasonable agreement between the experimental results and the certified values was obtained in most cases.
Improved model for the intensity of low‐energy tailing in Si(Li) x‐ray spectra
Authors: Campbell J. L. , Wang J.‐X. 
Published: May 2005

AbstractAccurate tail‐to‐peak intensity ratios are extracted from the spectra produced in a Si(Li) detector by x‐rays of energies 2–10 keV. The widely used model of a surface layer of incomplete charge collection fails to explain the energy dependence of these data. The model is augmented to include loss of photoelectrons travelling back into the ICC layer from an interaction in the active silicon region; this gives excellent agreement with experiment. It is shown that the detection efficiency in the region of low x‐ray energy may be deduced from the tail‐to‐peak ratios, together with measurement of the thicknesses of the beryllium window and the metal contact; a potential source of error in measuring the latter by the popular fluorescence technique is demonstrated.
Theory and numerical modeling of x‐ray fluorescence from multi‐layer spheres
Authors: Nordberg Martin E. 
Published: May 2005

AbstractA mathematical model has been developed for the quantitative x‐ray fluorescence spectrometry of small spherical samples, e.g. targets containing diagnostic materials for inertial confinement fusion experiments. The model corrects for matrix effects in a multi‐layer spherical geometry much as existing programs now do for thin films or bulk samples. Attenuation effects have been found to be greater in a shell geometry than in a comparable thin‐film geometry because multiple passes through the shell are possible and because many paths in or out are nearly tangential to the shell. In both cases the path is longer and attenuation is greater. The model for primary fluorescence from uniform shells has also been extended to approximate the fluorescence from non‐uniform shells. This allows one to predict how experimental results would vary with sample mounting if excess material were oriented toward or away from the x‐ray beam or the detector or away from both. Finally, a simplified model for estimating the magnitude of secondary fluorescence effects is presented.
PIXE and micro‐PIXE studies of exogenous element distributions in animal organs
Authors: Munnik F. , Mutsaers P. H. A. , Rokita E. , de Voigt M. J. A. 
Published: May 2005

AbstractA pilot study was undertaken with aluminium and strontium in order to determine the path taken when they enter an organism. Rabbits received an intramuscular injection of A1, and thin tissue cryo‐sections and pelletized and incinerated samples were investigated by the PIXE method. The best PIXE detection limits (ca. 60 μg g−1 dry weight) were obtained for thin tissue samples. On the basis of the chemical similarity of Ca and Sr, Sr ions were used to mark the Ca incorporation in the mineralized tissue. At different times of gestation (20–30 d), pregnant rabbits received an intraperitoneal injection of Sr. The animals were killed 7 h after the injection and the hind legs and skulls of the embryos were subjected directly to micro‐PIXE measurements. The results revealed that Sr incorporation in the embryo is an age‐dependent process. The highest Sr concentrations were found for 24‐d old embryos whereas at the end of gestation (30 d) the Sr concentration had decreased by a factor of ca. 10.
Comparison between two x‐ray analysis software packages
Authors: Boman J. , Isakson J. 
Published: May 2005

AbstractDifferent types of software for evaluating element concentrations from XRF spectra are based on different concepts and accordingly approach the problem in different mannners. Two software packages for analysis of XRF data were compared, the AXIL package, commercially available from Canberra‐Packard, and the XRFAES package, developed and used at the Department of Physics, Chalmers University of Technology, Göteborg. The experimental set‐up is presented and a presentation of the packages is given. The comparison is based on evaluation of biological and thin‐film samples and deals with: the possibility of analysing samples of different sizes, how the programs react to more or less erroneous input values of gain and zero energy and ease of use, i.e. calibration and different ways of entering input parameters and displaying results.
Polarization effects in a Si(Li) detector
Authors: Selin E. , Öblad M. , Standzenieks P. , Boman J. 
Published: May 2005

AbstractIn previous work time‐ and position‐dependent artifacts and a time‐dependent increase in the background radiation of x‐ray spectra was observed in planar Sl(Li)detectors for x‐rays in the keV region. In the present experiments the time‐dependent background was studied by use of a thin x‐ray beam. The time‐dependent background is considered to be due to incomplete charge collection. The amount of background is greater when the detector is left unexposed to x‐rays during the bias time than when the detector is constantly irradiated. The time‐dependent background was observed to decay with half‐lives of the order of 30 s, 10 min and 1–4 h. The results are interpreted such that polarization of the detector material occurs by traps that are formed under the influence of the bias voltage. During irradiation some of these traps are filled by charges from the hole‐electron pairs from the x‐ray beam. By using Ramo's theorem and converting the energy scale in the x‐ray spectra to detector depth, the polarization effect in the detector can be estimated to proceed with a speed of the order of 1 μm min−1 in an electric field of about 3000 V Cm−1.
Formulation of a universal electron probe microanalysis correction method
Authors: Scott V. D. , Love G. 
Published: May 2005

AbstractA new correction method for obtaining quantitative electron probe microanalysis results is described. It utilizes data provided by Monte Carlo simulations and tracer measurements to obtain a detailed picture of the way in which the x‐ray emission process is influenced by the relevant experimental parameters. Then empirical equations are derived which model the intensity of x‐ray emission for an extremely wide range of experimental conditions, encompassing electron beam energies from 5 to 40 keV, characteristic x‐ray wavelengths from 11.4 to 0.08 nm, angles of electron incidence from 90° to 40° and elements ranging from beryllium to uranium in the Periodic Table. The method treats separately, as with the traditional approach, the effects of atomic number difference in specimen and standard, x‐ray absorption and x‐ray fluorescence. The correction method was tested on an extensive range of microanalysis data and shown to work well under all conditions, providing chemical compositions which are accutate to within a few percent relative. The capability of handling ultra‐light element (beryllium to sodium) analysis is particularly impressive and the r.m.s. error of 3.8% for carbon analysis on carbides is very close to the errors incurred in measuring actual x‐ray intensities. The correction program is currently being developed for commercial use on IBM‐compatible computers and the final stage in the evolution of the universal correction will be to extend it to deal with the analysis of thin surface films.
Laboratory XAFS spectrometer for x‐ray absorption spectra of light elements
Authors: Yamashita Seiichi , Taniguchi Kazuo , Nomoto Seiichi , Yamaguchi Toshio , Wakita Hisanobu 
Published: May 2005

AbstractA new laboratory x‐ray absorption fine structure (XAFS) spectrometer specially designed for measurements of the absorption spectra of light elements is presented. The spectrometer consists of a newly developed rotating‐anode x‐ray source of portable size, a power supply of low‐voltage and high‐current type, a vacuum x‐ray path, a Johann‐type curved monochromator, a cell unit for high‐temperature measurements, and a solid‐state detector (SSD) system with a single‐channel analyser. The SSD system can eliminate x‐rays of other orders to give x‐ray absorption data containing no noise due to high frequencies. A current control method is employed to suppress characteristic x‐rays emitted from filament and target materials. The performance of the spectrometer was evaluated by x‐ray absorption measurements on a copper foil at the Cu K‐edge at room temperature and on powdered gibbsite and aluminosilicates at the Al K‐edge. The results showed that the spectrometer is capable of obtaining good quality XAFS and x‐ray absorption near‐edge structure (XANES) spectra at Al and Cu K‐edges within about 2 h. Thus, both XAFS and XANES studies will be possible with the spectrometer for a wide range of elements from sodium to lanthanides by use of suitable monochromator crystals.
Defects in glasses examined by backscattered electron imaging and by x‐ray wavelength and energy dispersive spectroscopy
Authors: Valdrè G. 
Published: May 2005

AbstractTypical optical defects in glasses with a high lead content were examined by backscattered electron imaging (BSI), quantitative energy‐dispersive x‐ray spectroscopy (EDS) and windowless EDS (WEDS) in a scanning electron microscope (SEM) and by quantitative wavelength‐dispersive spectroscopy (WDS) in an electron probe micro‐analyser (EPMA). Most of the images were obtained by using a backscattered electron (BSE) detector of high efficiency and excellent atomic number (Z) resolution (ΔZ = 0.3). The observations showed the presence of cords of varying shape, diameter (10–200 μm) and composition, spherical inclusions and fractures; the fractures were found to be associated with regions of materials of low Z which have developed gas under electron beam irradiation. Quantitative WDS and EDS microanalyses performed on the cords showed the presence of about 3 wt.% of Al2O3 and 2 wt.% of ZrO2, originating from the interaction, at the interface, of the glass and the refractory material used to hold the melted glass, and a lead content lower than the matrix. A high lead content was found, however, in the spherical inclusions. WDS and WEDS showed the presence of carbonates in the low‐Z regions, which probably developed CO2 under electron beam irradiation. These morphological and microchemical results are of great importance in clarifying the origin, and hence finding the means of avoidance, of defect formation.
Model for the multi‐element analysis of prestea gold ore with energy‐dispersive x‐ray fluorescence analysis
Authors: Aboh I. J. K. , Bamford S. Akoto , Tetteh G. K. 
Published: May 2005

AbstractEnergy‐dispersive x‐ray fluorescence (EDXRF) analysis using the fundamental parameters approach was used for the multi‐elemental analysis of Prestea (Ghana) gold ore (mill‐head samples). A model was obtained for the analysis based on the determination of the average total absorption in the ‘dark matrix’ (elements present but unable to be determined with the EDXRF spectrometer) of characteristic x‐rays of element i per percentage of the dark matrix (a%). The analytical procedure was validated using the reference sample IAEA SOIL‐7. There was good agreement between the model and calculated results.
Glass‐fibre filter for analysis of aerosol particles using energy‐dispersive x‐ray fluorescence
Authors: Salazar A. 
Published: May 2005

AbstractEnergy‐dispersive x‐ray fluorescence was used to analyse aerosol particles deposited on glass‐fibre filters. The blank filter contained several elements that interfered with trace elements found on the particles. The loaded filters were studied for composition and particle distribution of the few elements that can be analysed, which include lead. Samples provided by the Costa Rican Ministry of Health were analysed and the results presented.
Physical parameters for L x‐ray production cross‐sections
Authors: Puri S. , Chand B. , Garg M. L. , Singh Nirmal , Hubbell J. H. , Trehan P. N. 
Published: May 2005

AbstractPhoton‐induced L x‐ray production cross‐sections for the elements with 56 ≤ Z ≤ 92 were calculated at different energies in the range 11–60 keV using the photoionization cross‐sections based on the relativistic Dirac–Hartree–Slater (RDHS) model, fluorescence yields and Coster–Kronig transition probabilities based on the RDHS model and two sets of emission rates based on the Dirac–Fock (DF) model and the Dirac–Hartree–Slater (DHS) model. These calculated results were compared with the experimentally measured cross‐sections to check the applicability of emission rates based on the DF and DHS models.