bluuebunny/crossref_metadata_2025_split huggingface dataset:
Absorption correction in electron probe microanalysis
Authors: Gaber M. 
Published: May 2005

AbstractThe absorption correction factor f(χ) is calculated by using an empirical equation based on a new shape of the x‐ray depth distribution function Φ(ρz). It assumed that Φ(ρz) increases firstly linearly with the depth ρz up to the depth ρzm at which the function Φ(ρz) reaches its maximum value Φm, and subsequently the function Φ(ρz) decreases exponentially with increasing ρz. The proposed f(χ) equation is a function of the parameters ρzm, Φm and the mean depth of x‐ray production ρz. Based on Monte Carlo calculations, the variation of these parameters with the target atomic number Z, the incident electron energy E0 and the critical energy Ec was studied and empirical expressions were deduced. The calculated parameters were compared with experimental results. The factor f(χ) was calculated and compared with some measurements. The comparison gives an RMS error of 1.88%. The proposed equation was applied to 680 microanalysis data (including light elements). The results gave a relative deviation of about 3%, compared with 4.27% obtained by the quadrilateral model. For high absorbing systems (absorption factor ≤0.5), the present model gave an RMS error of 4.72% compared with 8.18% obtained by the quadrilateral model.
Chemical analysis of ream defect in float glass
Authors: Liu D. R. , Park J.‐S , Benoit R. E. , Jackson F. D. 
Published: May 2005

AbstractTo identify the source of a ream defect in float glass, the chemical composition of the ream has to be accurately determined, which can only be achieved by the electron probe microanalysis (EPMA) technique. Two ream samples were analyzed with EPMA. Because of the high mobility of the Na ion, caution had to be exercised to use a very low electron beam density during data acquisition. The results show that the reams in both cases are SiO2 rich, but one has more Na whereas the other has less Na than the base glass, pointing to possible different causes to the ream problems. In view of the fact that the compositional difference between a ream and the base glass is very small, several approaches were used to confirm the analytical results: the statistical t‐test, the digital elemental mapping and the compositional profiling. The differential etching analysis technique was also used to supplement the information on the chemistry and structure of a ream.
Review of φ(ρz) curves in electron probe microanalysis
Authors: Riveros José , Castellano Gustavo 
Published: May 2005

AbstractSeveral workers have proposed different models for the ionization distribution function ϕ(ρz), involving features related to the interaction of electrons with matter, e.g. ionization cross‐section, stopping power, electron back‐scattering and mass absorption coefficients (MACs). A number of expressions have been developed for these parameters, on which the accuracy of the correction procedures depends. This paper presents a comparison among three of the more successful models for ϕ(ρz): Packwood and Brown's Gaussian model, the quadrilateral model proposed by Sewell et al. and Pouchou and Pichoir's model.In order to test these models, a set of 1547 measurements in binary samples of known composition has been complied. Several models for the ionization cross‐section have been tested, along with different expressions for the mean ionization potential J, in which the shell effect can be taken into account. In addition, two possibilities for both the MACs and the electron backscattering coefficient are available. In general, all the tested models showed similar performances. Finally, the advantages of the models related to basic principles over the mathematically optimized ones, in the shape of ϕ(ρz) or in the parameters, are considered.
Collimated and windowless x‐ray microfluorescence analysis in a scanning electron microscope
Authors: Valdrè G. 
Published: May 2005

AbstractCollimated and windowless energy‐dispersive x‐ray microfluorescence (XRF) analysis was performed in a scanning electron microscope (SEM). The observation and the positioning of the specimen area to be analysed were made possible by using a specially designed collimation system utilizing holed targets or a side‐entry multi‐target rod. Trace element detection with a lateral resolution of about 300 μm was obtained. The combined use of a windowless energy‐dispersive spectrometer and a‐thin‐foil aluminium target improved the peak‐to‐background ratio especially for oxygen and sodium in a standard glass specimen. A brief discussion of the improvement of this SEM micro‐XRF technique is presented.
High‐precision non‐destructive x‐ray fluorescence method applicable to establishing the provenance of obsidian artifacts
Authors: Giauque Robert D. , Asaro Frank , Stross Fred H. , Hester Thomas R. 
Published: May 2005

AbstractA high‐precision, non‐destructuve x‐ray fluorescence (XRF) method has been developed for the determination of both trace and major elements in obsidian archaeological artifacts. Other than brushing the artifact surface clean, no sample preparation is required. The method developed proves XRF to be an extremely valuable technique for the analysis of archaeological obsidian samples which cannot be destroyed or altered because of their importance for historical studies. The method is applicable to both thick and thin samples which have wide variations in size and shapes. The method has been used to establish the provenance of a number of obsidian artifacts. The results ascertained for groups of samples from three provenances are discussed in this paper. The concentrations of thirteen trace (Ti, Mn, Zn, Ga, As, Rb, Sr, Y, Zr, Nb, Ba, Pb and Th) and three major (K, Ca and Fe) elements were determined from one x‐ray spectrum which was acquired during a 1000 s counting interval. The concentrations of the six most precisely measured elements (Fe, Rb, Sr, Y, Zr and Ba) yielded precisions which averaged 2.3%. The mean concentrations determined for five of these elements (excluding Y) differed on average by only 2.0% from published values which were ascertained by neutron activation analysis and XRF. The average standard deviations realized for the other ten elements determined was ca. 7%.
Coded imaging x‐ray microprobe
Authors: Bavdaz M. , Gurker N. 
Published: May 2005

AbstractAn experimental comparison is presented between line scanning (coded imaging) and conventional point scanning (direct imaging), based on experience gained with an x‐ray microprobe operated at the Hamburger Synchrotronstrahlungs‐Laboratorium (HASYLAB) at the Deutsches Elektronen‐Synchrotron (DESY). The microprobe uses synchrotron radiation to excite x‐ray fluorescence radiation in the sample, which is detected by a solid‐state detector and analysed for the element composition of the sample. The spatial distribution of elements, even if present only in traces, may be measured on a microscopic scale. Both methods were evaluated with regard to their imaging properties and compared with each other. The line‐scanning technique is shown to have a better signal‐to‐noise ratio, thus achieving a superior image quality. Some sample applications are described for illustration.
Determination of ωγ using the tilt of the propagation plane
Authors: Sánchez Héctor Jorge , Rubio Marcelo 
Published: May 2005

AbstractThe product of fluorescence yield (ω) and emission probability (Γ), was measured using a method based on the propagation plane inclination. Measurements of the Kα line of elements such as Cr, Fe and Ni on binary samples were carried out to determine the product ωΓ. The results were compared with those reported in well known compilations. The proposed procedure can be considered a new alternative to increase the available set of methods for measuring fundamental parameters.
Progress in X‐ray microbeam spectroscopy
Authors: Rindby A. 
Published: May 2005

AbstractX‐ray spectroscopy has been widely used for chemical analysis since its discovery in 1895. X‐ray fluorescence (XRF) has been used for over 60 years for identifying the elemental composition in most kinds of samples and in combination with modern semiconductor detector technology XRF has developed into a versatile, multi‐element method. With the high X‐ray flux attainable from the synchrotron source, new spectroscopic techniques have become available, such as extended x‐ray absorption fine structure (EXAFS) and x‐ray absorption near‐edge spectroscopy (XANES), for studying the chemical states of the different elements. With the use of high‐intensity x‐ray microbeams all of these different analytical methods can be performed on a microscopic level. By scanning the microbeam over a sample, the distribution of different elements can be determined. A description of the basic principles of x‐ray microbeam spectroscopy, and the historical background, is given and comparisons with other techniques are discussed. Different techniques for focusing of x‐rays, detection and image reconstruction are described. Examples of applications and future perspectives are discussed with particular emphasis on capillary optical systems.
EDXRS study of aerosol composition variations in air masses crossing the North Sea
Authors: Injuk J. , Van Malderen H. , Van Grieken R. , Swietlicki E. , Knox J. M. , Schofield R. 
Published: May 2005

AbstractX‐ray emission techniques for bulk and individual particle analysis (EDXRF, EPXMA, micro‐PIXE) were combined and applied in atmospheric research on the North Sea area as part of a field‐study on air‐sea exchange processes of particulate matter. The atmospheric loading for a number of elements was determined by EDXRF, yielding bulk concentrations for Mg, Al, Si, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Br and Sr. From these EDXRF data, deposition rates were derived and, based on a classical multivariate statistical approach, different aerosol sources were identified. Complementary to this work, EPXMA combined with automated image analysis was applied to individual size‐segregated aerosol particles to determine their inorganic composition, physical size and shape. Also, the first results of micro‐PIXE analyses on individual North Sea aerosol particles, particularly their large‐size fraction, are discussed and compared with the corresponding EPXMA results. In summary, such a joint approach with the use of different x‐ray emission techniques contributed to the resolution of the mixed structure of the lower North Sea troposphere and to the determination of the atmospheric supply of material to the North Sea environment.
Synchrotron x‐ray fluorescence analysis of heavy trace elements in light silicate minerals
Authors: Figueiredo M. O. , Basto M. J. , Abbas K. , Chevallier P. , Melo Z. , Ramos M. T. 
Published: May 2005

AbstractA description is presented of fluorescence spectrometric experiments using synchrotron radiation and an energydispersive detection system performed at the LURE (DCI storage ring) where a study of geological materials is under development. Early results obtained for natural lithium aluminosilicates (lepidolites) from pegmatite formations in northern Portugal are discused. Data handling and processing (deconvolution of the complex spectral lines, deduction of continuous background and peak area calculation) are briefly described. Some heavy trace elements previously unreported for these lepidolites (TI, W, Ta, Nb) and one geochemically relevant sub‐trace metal (Au) were detected. The analytical efficiencies of three excitation energies (6, 13 and 19 keV) are compared. The difficulities and drawbacks versus advantages of this techique for the assessment of trace and sub‐trace elements in geological samples are discussed.
Proton‐induced monochromatie x‐ray beams
Authors: Karydas A. G. , Paradellis T. 
Published: May 2005

AbstractThe bombardment of thick pure targets by protons produces intense monochromatic x‐ray beams which can be used for x‐ray fluorescence analysis. An experimental arrangement suitable for sample irradiation and detection of the fluorescent x‐rays in vacuum was constructed and was attached to the accelerator leg. The general characteristics of the method are described and some examples from the use of Cu, Fe and Ti as primary targets are presented.
A fast convergence procedure for a direct determination method in XRF
Authors: Wang Yongzhong 
Published: May 2005

AbstractA comparison among current methods in x‐ray spectrometry showed that it is possible to abandon the traditional concept of comparing unknown samples with standards if it is expected that unknown samples with a rough surface can be determined directly without sample preparation. The error caused by the uncertainties of the fundamental parameters can be reduced and the effect of the attenuation in the x‐ray path on the intensities of the characteristic fluorescent x‐rays can also be accounted for by the introduction of the instrumental factors Pik which are initially determined. In order to speed up the calculation, a new iterative equation is presented in the direct determination method. In addition, a new way to select the starting values in the iteration and a simplified way to iterate the calculation are presented. With these improvements, the convergence in iteration is faster than before.
Intensities of individual L x‐ray spectra calculated using the TEREN program
Authors: Verkhovodov Peter A. 
Published: May 2005

AbstractIn characteristic x‐ray intensity calculations, the total L spectrum can be represented by separate spectra from L1, L2 and L3 subshell transitions. The expressions presented here take into account the ionization not only of the L1, L2 and L3 subshells but also of the K shell. The approximating polynomials for the calculation of the radiative transition probability and the Koster‐Kroning transition probability are derived. Examples are presented of intensity calculations in multi‐component systems using the TEREN program.
Anomalous X‐ray absorption of the Mα lines in the rare earth elements
Authors: Lábár János L. 
Published: May 2005

AbstractThe presence of an unfilled inner electron shell in the rare earth elements is manifested in x‐ray absorption effects that are unique to the energy region including the Mα and Mβ lines of these elements. In contrast to the normal edge‐type absorption, this anomalous absorption appears as an absorption line. A method is presented here for the quantitative determination of the extent of this anomalous absorption. Solid bulk metal samples, excited with a monoenergetic electron beam, were examined with a wavelength‐dispersive x‐ray spectrometer. The discussed method makes the experimentally determined absorption independent of both the detection efficiency and atomic data such as the fluorescence yield and transition probabilities. A simple empirical model is proposed to explain the dependence of the absorption of the Mα line on the absorption path length, which was varied by the primary beam energy. Normal and anomalous absorption are treated as independent and competing processes in this model. Atomic data such as the mass absorption coefficients pertinent to the anomalous absorption of the Mα lines were also determined and are presented.
X‐Ray fluorescence analysis with elements having overlapped lines
Authors: Mainardi Raúl T. , Barrea Raúl A. 
Published: May 2005

AbstractThe overlapping of characteristic spectral lines of two or more elemental constituents of a sample has always been a drawback in x‐ray fluorescence analysis. A new approach to solve this problem is presented, based in the excitation at two different energies. The results show that it is possible to calculate the concentration of elements with overlapped lines with high accuracy. We thus avoid the use of other means to obtain the needed number of spectral lines, such as secondary characteristic lines, which usually have a low peak to background ratio, or to recur to the line fraction (i.e. Kβ/Kα), which is matrix dependent.
Energy‐dispersive XRF analysis of pure element intensities from their oxides using a Cd‐109 source
Authors: Hua Younan , Yap C. T. 
Published: May 2005

AbstractThe relationship between the fluorescent intensity ratio of analyte to pure analyte/concentration of analyte and the fluorescent energy can be expressed as In(Ii/Ii0ci) = a In Ei + b, where a and b are constants for a given matrix. This relationship depends on the pure element intensity Ii0. Experimental pure element intensities can be obtained in a number of ways. Although the use of thick pure metal foils is perhaps the simplest, there are many elements for which pure metal foils are not available. This paper discusses the determination of experimental values of pure element intensities from their oxides and shows that their values are in good agreement with those obtained from pure metal foils.
Effect of features of inner atomic shells excitation by accelerated ions on the shape of the emitted X‐ray lines
Authors: Altynov V. A. , Blokhin S. M. 
Published: May 2005

AbstractA study of the effects of various factors in forming the structure of the characteristic x‐ray spectrum of atoms excited by heavy ions with an energy of ca. 1 MeV u−1 is reported. In particular, the structure of multiple ionization satellites was analysed and also the effect of the bombarding ion field and the reflection in the emitted spectrum of the Doppler‐shaped lines connected with the presence of the emitting atom recoil velocity. It is shown that the experimental shape of the corresponding x‐ray lines is satisfactorily reproduced if the contribution of the effects under investigation is taken into account.
Efficiency calibration of a Ge(In) semiconductor detector by thin‐ and thick‐arget PIXE
Authors: Kallithrakas‐Kontos N. , Katsanos A. A. 
Published: May 2005

AbstractThe efficiency of a Ge(In) semiconductor x‐ray detector was measured in the energy region 1‒25 keV using proton‐induced x‐rays from thick targets and from thin targets of standard thickness, and the results of the two calibration methods were compared. A proton energy of 2.00 MeV was used in an external beam facility. A model based on fundamental parameters (mass absorption coefficients, fluorescence yields and relative x‐ray emission rates) was used to reproduce the experimental results.
Method for quantitative electron microprobe EDS X‐ray analysis of small incluasions in matrices with similar composition
Authors: Stoyanchev R. , Iliev Tz. , Recalov K. 
Published: May 2005

AbstractA method is proposed for the quantitative elemental analysis of small inclusions in matrices with similar composition. The method is applicable provided that the difference between the matrix and the inclusion is at least one x‐ray‐detectable element. The approach is based on a technique for the determination of phase fractions by scanning the surface of the sample by the electron beam and recording the x‐ray intensities with an energy‐dispersive x‐ray spectrometer. By using the phase fraction of the matrix as a multiplier–coefficient, the contribution of the matrix to the overall area‐scanned spectrum around the inclusion is determined. Then the contribution of the matrix in the same spectrum is subtracted from the overall area‐scanned spectrum. The elemental composition of the remaining spectrum is analysed by the standardless ZAF method. The new method was tested experimentally with different sulphide inclusions within sulphide matrices.
Kinetic equation‐based calculation of the electron distribution in the target exposed to the electron beam
Authors: Bakaleinikov L. A. , Tropp E. A. 
Published: May 2005

AbstractSingular perturbation methods were used to investigate the kinetic equation for electron distribution in targets. This approach permits the determination of the domains of applicability of kinetic equation approximations and the establishment of the connections between them. The analytical solution of the approximate kinetic equation in some of these domains was obtained and numerical calculations were performed in the others. On the basis of these solutions, the energy spectrum of backscattered electrons and the x‐ray depth distribution were found.
Quantitative analysis of some elements of aydin basin soils by X‐ray fluorescence spectrometry
Authors: Bassari Asiye , Kumru Mehmet 
Published: May 2005

AbstractSoil samples from 40 different sampling points in the Aydin Basin were analysed and the distributions of Ti, Cr, Mn, Cu, Zn, Sr, Zr, Rb, Ba and Ce were investigated by energy‐dispersive x‐ray fluorescence spectrometry. Two annular sources, 238Pu (10 mCi) and 241Am (30 mCi) and two detectors, Si(Li) and HPGe, were used. The fundamental parameter technique was adopted for quantitative analysis of elements. The concentrations of Cr, Zr, Zn and Ce were found to be higher than those corresponding to the mean chemical composition of the lithosphere.
A novel method to ascertain sample mass thickness and matrix effects for X‐ray fluorescence element determinations
Authors: Giauque Robert D. 
Published: May 2005

AbstractAn x‐ray fluorescence method was developed for the determination of both trace and major elements in environmental samples that are primarily of geochemical origin. For analysis, unweighed finely pulverized sample material is lightly compressed to a mass thickness between 0.1 and 0.4 g cm−2. The method utilizes the relative intensities of two incoherent and one coherent scattered excitation radiation to ascertain the sample mass thickness and the photoelectric cross‐section of the sample for the excitation radiation. This information is employed to calculate matrix absorption and enhancement effect corrections required for the individual element determinations. The intensity of one of the incoherently scattered radiations serves as an internal standard for all of the element determinations. The capability of the method has been demonstrated with three US National Institute of Standards and Technology reference materials. The concentrations of sixteen trace elements (Mn, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th) and four major elements (K, Ca, Ti, and Fe) were determined from one x‐ray spectrum which was acquired over a 1000 s counting interval.
An analytical algorithm for correction of edge effects in X‐ray microfluorescence analysis of geological samples
Authors: Lankosz Marek , Pella Peter A. 
Published: May 2005

AbstractGeometrical effects occur when primary x‐rays irradiate a mineral inclusion which lies close to the boundary between it and a surrounding mineral having a different chemical composition. An investigation of two types of near‐edge effects was performed in the case when x‐ray microfluorescence is applied for analysis. For zinc sulfide in calcium carbonate and for arsenopyrite in serpentine, the increase in measured characteristic x‐ray intensity near the boundary is 15‒25%. Analytical mathematical expressions were developed to correct for such effects and the calculated results are in good agreement with measured values.
Quantitative total reflection X‐ray fluorescence analysis with monoenergetic excitation
Authors: Ladisich Wolfgang , Rieder Robert , Wobrauschek Peter 
Published: May 2005

AbstractBy applying monoenergetic excitation in total reflection x‐ray fluorescence analysis, the quantitative analysis can be further simplified since fundamental parameters from tables can be used for the calculation of elemental sensitivities. Establishing calibration graphs experimentally by measuring multielement standards is no longer necessary. Advantages of monoenergetic excitation are discussed.