bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polarization effects in x‐ray photon diffusion
Authors: Fernández J. E. 
Published: May 2005

AbstractPolarization effects in x‐ray spectrometry are explained with recourse to transport theroy. Intensity contributions from multiple‐scattering terms of the Rayleigh and Compton effects calculated with two models, one representing rigorously the polarization state (vector model) and the other approximating the effects of polarization by considering always the same average state (scalar model), are compared to show the influence of polarization in a practical way. It is shown that using average polarization represents a first‐order approximation valid for unpolarized source.s As a paradigmatic example it is shown that the full account of polarization, for the case of a sample irradiated with an unpolarized x‐ray source (i.e. x‐ray tube), increases the estimated intensity of the multiplescattering background without modifying the intensity of the first‐order term. The effect of polarization is zero or can be neglected in those scattering chains which contain at least one photoelectric effect. In contrast, it must be considered to correct the computation of the continuous background under the Compton peak, due to collision events of the Rayleigh and Compton effects.
Characteristics of layered synthetic microstructure devices for x‐ray spectrometry applications
Authors: Biltoft P. J. 
Published: May 2005

AbstractMulti‐layer structures offer the unique ability to control the spectral distribution of x‐rays non‐grazing incidence and to provide the ability to focus x‐rays. This combination of attributes offers some exciting possibilities for x‐ray spectrometry. Double crystal monochromators using multi‐layer structures have shown high energy selectivity with reasonable throughput X‐ray optical systems using multi‐layers deposited on figured substrates have been used to focus x‐rays from a conventional tube to micron‐sized spots. Future x‐ray spectrometers will likely take advantage of the energy selection and focusing capabilities of multi‐layers as they become more readily available. Topics covered in this paper include the modification of spectral emissions from a conventional copper anode x‐ray tube by a multi‐layer, and multi‐layer fabrication and characterization techniques as they apply to energy‐dispersive x‐ray spectrometry.
The number of Kα photons produced on a set of thin targets as a functional description of the fluorescence exciting x‐ray beam
Authors: Delgado Martínez V. , Martínez Hidalgo C. 
Published: May 2005

AbstractThis work suggests a theoretical approach for the description of a primary x‐ray beam by means of the K fluorescence which it excites on a set of thin targets made of pure elements. Physical quantities, defined as weighted integrals over hv of the photon spectral distribution, are obtained directly as weighted integrals of the Kα yields over the variable Ez (the ionization energy of the K shell of the element with atomic number Z), without needing any explicit reconstruction of the spectral distribution. The set of Kα yields produced by an x‐ray beam as a function of Ez is a functional description of the exciting beam. Theoretically, such a description is suited to x‐ray fluorescence analysis.
Sensitive method for the determination of rare earth elements by radioisotope‐excited XRF employing a high‐purity germanium detector in optimized geometry
Authors: Lal Madan , Bajpal H. N. , Joseph Daisy , Patra P. K. 
Published: May 2005

AbstractA close‐coupled side‐source geometrical configuration is proposed for obtaining a high detection sensitivity for rare earth elements (57 ⩽ Z ⩽ 69) by radioisotope‐excited energy‐dispersive x‐ray fluorescence spectrometry. In this configuration a disc source of241 Am (100 mCi), a high‐purity germanium detector and thin samles of rare earth elements on a Mylar backing are employed in an optimized geometry to achieve detection limits in the range 20–50 ng for these elements in a counting time of 1 h.
L shell fluorescence yields and coster—kronig transition probabilities for the elements with 25 ⩽ Z ⩽ 96
Authors: Puri S. , Mehta D. , Chand B. , Singh Nirmal , Trehan P. N. 
Published: May 2005

AbstractThe values of Li sub‐shell fluorescence yields (ωi) and Coster–Kronig transition probabilities (fij) were evaluated using radiative and non‐radiative transition rates based on the relativistic Dirac–Hartree–Slater (RDHS) model for all the elements in the atomic number range 25 ⩽ Z ⩽ 96. The values of the Coster–Kronig‐corrected fluorescence (vi) and average L shell fluorescence (ϖL) yields were also evaluated and least‐squares fitted to obtain the polynomials representing them as a function of atomic number.
Mα/Lα intensity ratios for Ta, W, Pt, Au, Pb and Bi for electron energies in the 11–40 keV range
Authors: Trincavelli J. , Montoro S. , Van Espen P. , Van Grieken R. 
Published: May 2005

AbstractBoth energy‐ and wavelength‐dispersive systems were used to obtain Mα/Lα intensity ratios for Ta, W, Pt, Au, Pb and Bi at various overvoltages. A table of these ratios corrected for matrix absorption and detector efficiency is presented, in addition to an interpolatory function of Mα/Lα generated ratios vs. overvoltage, for each element. In addition, three different ZAF correction models were used to predict both detected and generated ratios. Finally, experimental Mβ/Mα ratios measured at different overvoltages are presented for the six elements considered.
Determination of incident angle in radioisotope‐excited EDXRF
Authors: Somogyi A. , Pázsit Á 
Published: May 2005

AbstractThree different methods were used for the determination of the effective incident angle related to EDXRF when radioisotope annular sources are involved: weighted averaging, Compton peak method and minimization of the difference between the certificated and measured concetrations of six international standard samples. By measuring the Compton peak energies of various analytical reagent grade elements and compounds, it was found that the incoherent peak energy depends on the mean atomic number of the matrix, so the effective incident angle is also matrix dependent.
Simultaneous matrix and background correction method and its application in XRF concentration determination of trace elements in geological materials
Authors: Hua Younan , Yap C. T. 
Published: May 2005

AbstractCompton scattered radiation has been used as an internal standard to compensate for matrix absorption effects; it has also been used separately for background correction. In this work, the simultaneous matrix and background correction method was developed, in which both matrix absorption effects and background correction are performed simultaneously, thereby reducing the measurement time; this is particularly important when dealing with large numbers of samples. It also obviates the problem in the conventional method of correcting for the background when the interference‐free background position near the spectral peaks cannot be found. Application of this method to a large number of geological standard reference materials yields values of trace element concentrations in good agreement with their recommended values.
Lowering the limits of detection of X‐ray fluorescence analysis in the electron microscope
Authors: Barna Á. , Pozsgai I. , Fiori C. E. , Wight S. A. 
Published: May 2005

AbstractA transmission‐type attachment for energy‐dispersive x‐ray fluorescence analysis was developed. The attachment was designed for analysis to be carried out in a CAMEBAX microanalyzer, where the energy‐dispersive spectrometer detector views the specimen through a hole in the objective lens and the space between the specimen and the pole piece of the objective lens is fairly small. Nevertheless, this type of attachment can be applied in other microanalyzers or scanning electron microscopes. Detection limits between 0.5 and 5 ppm on SRM 612 glass (NIST) and the applicability to the analysis of small particles (SRM 470 glass sphere 90 μm in diameter) are demonstrated.
Analysis of archaeological pottery by X‐ray fluorescence spectrometry applying the limit dilution method
Authors: Carbó M. T. Doménech , Reig F. Bosch , Adelantado J. V. Gimeno , Martinez V. Peris 
Published: May 2005

AbstractA method for correcting the intensity of x‐ray fluorescence (limit dilution method) is proposed for the analysis of samples with a complex matrix such as ceramic materials of archaeological interest. This method corrects the interelement effects, resolving the wide deviations which occur in the quantitative results obtained by x‐ray fluorescence without correction. The contents of sodium, magnesium, aluminium, silicon, potassium, calcium, titanium and iron in sixteen archaeological ceramic samples of different origins and from different locations were determined. The results obtained are comparable to the values obtained by chemical analysis. A statistical study of the data was carried out to classify the samples hierarchically by cluster analysis of their chemical composition and loss on ignition.
Quantitative analyses of aerosol filters by wavelength‐dispersive X‐ray spectrometry from bulk reference samples
Authors: Quisefit J. P. , de Chateaubourg P. , Garivait S. , Steiner E. 
Published: May 2005

AbstractThe quantitative analysis by X‐ray Fluorescence (XRF) of aerosol filters implies the use of calibration curves obtained from synthetic standards which are relatively difficult to make. Several methods have been developed in the last 10 years. Because of transparency to the exciting X‐rays, the analysis of thin films requires optimization of the sample holder by adding secondary covers, for which the influence of the nature and form of the material to obtain the best detection limits has been studied previously. In addition, some metallic solid samples defined as ‘;filter equivalent’ samples have been used by other workers, but only for lead determination, and without a study of their capability to take into account any instrumental variations. This paper reports a theoretical and practical study of bulk samples defined as ‘;filter equivalents.’ Their capability of always being reliable standards even with large variations in instrumental conditions was controlled. A general process to make multi‐element bulky ‘;filter equivalents’ by means of borate glass discs is described. These have the great advantage of being very easy to manipulate and less fragile than thin films or filters, and resistant to X‐rays even after several calibration checks carried out to estimate the stability of the apparatus. They should have an ‘;infinite lifetime’ if the analyst correctly manipulates and stores them.
Wavelength‐Dispersive X‐ray fluorescence spectrometric technique for determining elements in weld fumes
Authors: Swamy K. , Kaliaperumal R. , Swaminathan G. S. 
Published: May 2005

AbstractAn x‐ray fluorescence spectrometric method is described for the determination of elements present in the fumes evolved during welding. Synthetic standards were prepared using salts of Si, Mn, Cr, Fe, Pb, Cu, Al and Ni for evaluation. The standards were mixed with boric acid in the ratio 1 : 1 and briquettes were prepared by the double pellet method. The samples were collected in filter‐paper discs by exposing them during welding. The average standard deviation of the method is about 7%.
Relative intensities of Lα1, Lβ1 and Lβ2, 3, 15 lines of gold: Photoexcitation with the continuum in and near the threshold region
Authors: Agrawal R. M. , Jha S. N. 
Published: May 2005

AbstractVariations of the relative intensities of the Lα1, Lβ1 and Lβ2,3,15 lines of gold on their photoexcitation with the continua of x‐ray tubes with W and Mo targets were measured at operating voltages from 15 to 20 kV. The standard procedure for calculating the fluorescence intensity of an x‐ray line excited by a polychromatic x‐ray beam was suitably modified to calculate the relative intensities of these lines. The factors responsible for the differences between the experimental and calculated values are discussed.
Scanning electron microscopy and X‐ray energy‐dispersive spectroscopy of surface micro‐transformations in Ca–P glasses
Authors: Valdrè G. 
Published: May 2005

AbstractSurface transformations of micro‐granules of a calcium‐phosphate glass (a bio‐glass) were examined by back‐scattered electron (BS) imaging and quantitative x‐ray energy‐dispersive spectroscopy (EDS) in a scanning electron microscope (SEM). All the images were obtained by using a backscattered electron detector of high efficiency and atomic number Z resolution (ΔZ = 0.3). The chemical transformations were induced during in vivo implantation of the bio‐glass in rabbit dorsal muscle sites. The observations showed the presence of an interlayered structure with different BS signal contrast. Quantitative EDS microanalysis performed by profiling the electron beam across the samples indicated the presence of hydrated calcium‐phosphate in the external layer, an inhomogeneous silica‐rich gel‐type layer in the mid‐layer and unaffected original Ca–P glass in the centre. A simple model, based on the balance of the concentrations of the elements (which have diffused) in the different layers, is proposed to explain the contribution of the elements constituting the original glass to the formation of the different layers. This result agrees with the experimental data obtained from image analysis. The microstructural behaviour of this type of glass was elucidated.
Effect of counter ions on X‐ray absorption discontinuity
Authors: Khadikar Padmakar V. , Joshi Shobha , Mangalson Nolan F. , Silk Jeffrey E. 
Published: May 2005

AbstractThis work indicates that counter ion distant neighbours affect the x‐ray absorption discontinuity. Cobalt(III) complexes of ethylenediamine containing different counter ions were used as models for this purpose. The results should provide useful information regarding the influence of counter ion distant neighbours on x‐ray absorption spectra.
Measurement of composition of thin films obtained by sputtering using radioisotope excited X‐ray fluorescence
Authors: Moore J. A. , Elsahlli T. 
Published: May 2005

AbstractAn energy‐dispersive x‐ray fluorescence (EDXRF) apparatus using a radioisotope source with a secondary target (241 Am–Mo) and a Si(Li) x‐ray spectrometer was used to measure the Cu, Sr and Bi contents of thin (100 μg cm−2) films sputtered on to MgO. The results were found to be in excellent agreement with those obtained from MeV Rutherford backscattering (RBS) analysis of the same films. The calibration of the EDXRF apparatus was done by measuring x‐ray intensities excited in thin sol‐gel films of known Cu, Sr and Bi content, as given by the accurately known chemical solutions from which the sol‐gel films were prepared. The experimental calibration constants were in excellent agreement with the theoretical values calculated using a thin‐film equation, which assumes that characteristic x‐ray absorption and secondary excitation are negligible, and the published atomic x‐ray data.
Application of synchrotron radiation XRF analysis in high‐temperature superconducting thin‐film technology
Authors: Trounova V. A. , Danilovich V. S. , Zolotarev K. V. , Predtechensii M. R. , Bobrinok O. F. 
Published: May 2005

AbstractThe method of synchrotron radiation XRF applied to high‐temperature superconducting films can be used for the measurement of the compositions of different compounds of the same element or of the changes in the stoichiometry in the process of thin‐film production. An important advantage of the method is that it possesses very low detection limit (down to 5 × 1013 atoms cm−2) and allows a wide range of film thicknesses to be measured.
Submicrometer phase chemical composition analysis with an electron probe microanalyzer
Authors: Wang Frank Cheng‐Yu 
Published: May 2005

AbstractSubmicrometer phase quantitative analysis is always a challenging problem for electron beam microanalysis because the phase is smaller than the electron beam and the specimen interaction volume. In order to obtain more accurate composition information, other analytical techniques need to be used to clarify the elements present and characterize the valence state of major elements in that submicrometer phase In this study, the electron probe microanalyzer (EPMA) was used to determine the contamination phase in the tungsten carbide‐cobalt ceramic system. The average size of the contamination phase was approximately 0.5 μm in diameter. The chemical composition of the contamination phase was elucidated by combining results from x‐ray mapping, valence state determination and EPMA quantitative analysis data. The effect of the contamination phase in the tungsten carbide‐cobalt ceramic system is also discussed.
Ll, Lα, Lβ and Lγ X‐Ray Production Cross‐Sections in Elements 57 ≤ Z ≤ 92 by 8–50 ke V Photons
Authors: Mann K. S. , Singh N. , Mittal Raj , Sood B. S. , Allawadhi K. L. 
Published: May 2005

AbstractCross‐sections for the production of Ll, Lα, Lβ and Lγ x‐rays in 22 elements (57 ≤ Z ≤ 92) by photons of 13 different energies in the range 8–50 ke V are reported. The experimental values of the cross‐sections were determined by measuring the absolute yield of L subshell x‐rays emitted from a target of a given element and thickness when it was bombarded with a known flux of photons of given energy. The theoretical values of the cross‐sections were calculated from the theoretical/semi‐empirical values of subshell photoionization cross‐sections, fluorescence yields, Coster‐Kronig transition probabilities, intra‐shell transition probabilities and radiative decay rates. The present and previous measured and calculated values of the cross‐sections are tabulated to bring out the existing status of L x‐ray production cross‐sections.
Elemental analysis of gel‐grown rare earth molybdate crystals using energy‐dispersive X‐ray fluorescence spectrometry
Authors: Bhat C. K. , Bhat C. L. , Lal Madan , Patra P. K. , Kotru P. N. 
Published: May 2005

AbstractRare earth molybdate crystals such as those based on lanthanum, neodymium and some mixed molybdates, grown by the gel method, were analysed for major and trace impurity elemental concentrations using energy‐dispersive X‐ray fluorescence spectrometry in order to understand the characteristics of the material in terms of structural perfection and composition. The method used permits the simultaneous determination of rare earth elements such as La and Nd and also Mo and impurities such as Fe and Zn. Based on the observed concentrations of major elements, it is shown that the formulae so far assumed for some of these composites may be incorrect and may need a major refinement. Monoenergetic X‐rays of 22.1 and 59.6 keV were employed for fluorescence excitation and optimum detection efficiency was obtained for a large number of elements. Pulverized samples mixed with cellulose powder and specimens prepared in the form of pellets were used. The fundamental parameter method was used for the quantitative estimation of elemental concentration.
Peak‐to‐background method for standardless electron microprobe analysis of particles
Authors: Trincavelli J. , Van Grieken R. 
Published: May 2005

AbstractA peak‐to‐background method was implemented for standardless electron microprobe analysis of bulk samples and particles. First, a study on the choice of the beam entry point was performed; the region of the particle closest to the detector proved to be the most convenient. Then, a very simple algorithm, which does not require any kind of standard, was developed for particle analysis. This method was tested for glass standard particles and the results were compared with those given by other methods; the proposed standardless approach appeared to yield very satisfactory results.
Investigation of M x‐ray emission following photoionization of L and M shell electrons in high‐Z‐elements
Authors: Allawadhi K. L. , Sood B. S. , Mittal Raj , Singh N. , Mann K. S. , Vandana  
Published: May 2005

AbstractThe cross‐sections of M x‐ray emission following photoionization of L and M shell electrons in Au, Pb, Th and U by 59.57 ke V gamma rays were measured. The experimental values of cross‐sections were found to be higher than those calculated from the theoretical values of L and M shell photoionization cross‐sections, the Li subshell to M shell vacancy transfer probabilities and M shell average fluorescence yields. The transfer of vacancies from the Li subshell to the M shell was found to play a significant role in M x‐ray emission. The present status of the experimental and calculated values of the cross‐sections is discussed.
Comparison of the determination of copper, nickel and zinc in contaminated soils by x‐ray fluorescence spectrometry and inductively coupled plasma spectrometry
Authors: Wilson P. , Cooke M. , Cawley J. , Giles L. , West M. 
Published: May 2005

AbstractSoil samples from a potentially contaminated site were prepared and analysed for their copper, nickel and zinc contents by both inductively coupled plasma (ICP) spectrometry and x‐ray fluorescence (XRF) spectrometry. Results obtained by XRF spectrometry were either comparable with or slightly higher than those obtained by ICP. However, when the results obtained by the two techniques were compared with the threshold values for contamination by the three metals, then each set of results led to the same conclusion with respect to the categorization of the site. Comparability between the two techniques was thus demonstrated and either may be used to screen soil for phytotoxic metals.
EDXRS study of lichens as biomonitors and effects of washing procedure on element concentrations
Authors: Calliari I. , Caniglia G. , Nardi S. , Tollardo A. M. , Callegaro R. 
Published: May 2005

AbstractA monitoring survey was carried out in North Italy using Pseudevernia furfuracea as a monitor of air pollution. The experiment was carried out on lichen thalli exposed for different periods varying from 3 to 10 months at urban and rural sites, to examine and compare the bioaccumultion of several elements. Every 2 months a fraction fo exposed lichens was collected to analyse the theallus. Each fraction was divided into two parts, one of which was washed in deionized water, in order to quanify the element loss due to the washing procedure. The samples were analysed by energy‐dispersive x‐ray fluorescence spectrmetry in the secondary excitation mode; quantitative analysis was performed by the fundamental parameter method with NIST standard reference materials. The targets for the fluorescence spectrometer were obtained by digestion under pressure with microwave heating. At the end of the exposure period (10 months), nearly all elements, showed highter concentrations at the urban than at the rural site.
L‐subshell Coster–Kronig yields for Tb
Authors: Sánchez Héctor J. , Pérez Roberto D. , Rubio Marcelo , Castellano Gustavo 
Published: May 2005

AbstractThe synchrotron photoionization method was applied to measure L‐subshell Coster–Kronig yields for Tb. This method is based on the capability of tuning the energy of the synchrotron photons producing a selective subshell ionization. A foil sample of Tb was irradiated and characteristic spectra were recorded. Data were analysed using a new formalism (based on a matrix representation) to express x‐ray fluorescence intensities involving Coster–Kronig transitions. The results obtained were f12 = 0.201 ± 0.014, f13 = 0.281 ± 0.027 and f23 = 0.097 ± 0.016. These data represent valuable information for spectroscopists, considering the lack of data for L‐shell parameters.