bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorescence cross‐sections for L shell x‐ray lines
Authors: Bhan Chander , Chaturvedi S. N. , Nath N.
Published: May 2005

Absolute values of x‐ray fluorescence (XRF) cross‐sections for Lα lines have been calculated for all the elements with 47 ≤ Z ≤ 92 at two exciting energies corresponding to Ag and Te K x‐rays from 10Cd and 125I radioisotopes, respectively. The effect of hole transfer within L subshells is also included when calculating the cross‐sections. Experimental measurements were carried out for Lα, L1 and LTotal x‐ray fluorescence cross‐sections for some of the elements ranging from Ho to U using exciter sources of 109Cd and 125I. Average L shell fluorescence yields were also obtained using the measured values of total L shell x‐ray fluorescence cross‐sections and the theoretical values of photoelectric cross‐sections.
Monte Carlo simulation of backscattered peaks in secondary target energy‐dispersive x‐ray spectra
Authors: Van Dyck Peter , Török Szabina , Van Grieken René
Published: May 2005

A Monte Carlo simulation has been developed to describe the incoherent and coherent scatter processes for the complex geometry of a secondary target energy‐dispersive x‐ray fluorescence system. Photons are followed from the x‐ray tube anode until the detection of scattered secondary target photons in the active Si layer of the detector. The program quantitatively shows the broadening of the incoherent scatter peak with increasing atomic number, and it models the incoherent peak shape adequately. The incoherent‐to‐coherent scatter intensity ratios obtained differ by 10–30% from the theoretical values, while their dependence on the sample atomic number corresponds to that expected from theory.
Intercomparison of fundamental parameter interelement correction methods—part 2
Authors: Pella P. A. , Tao G. Y. , Lachance G.
Published: May 2005

Intercomparison of fundamental parameter interelement correction methods is extended to include α‐coefficient algorithms in which the coefficients are calculated from fundamental parameters. Several of these methods are intercompared, including a comprehensive α‐coefficient algorithm recently proposed by Lachance. Results of the analysis of alloys, pressed cements and fused specimens are presented.
Calculation of relative x‐ray fluorescence intensity for annular‐source geometry by the Monte Carlo method
Authors: Tang S. M. , Kump P. , Yap C. T. , Bilal M. G.
Published: May 2005

The calculation of relative x‐ray fluorescence intensity for annular‐source geometry by the Monte Carlo method is reported. The K x‐ray fluorescence intensities for different specimen positions were measured and found to be in excellent agreement with the calculated values. The same method was used to obtain the distribution of excitation intensity across the specimen surface. The usefulness of the results of such a calculation is discussed.
Mean energy of backscattered electrons at various angles of incidence
Authors: Gaber M.
Published: May 2005

Using Monte Carlo simulations, the mean energies of backscattered electrons for thick targets of aluminium, titanium, iron, molybdenum, tungsten and lead were calculated at various angles of incidence and an incident electron energy E0 of 30 keV. The results show that the mean energy ratio, ĒB/E0, of backscattered electrons depends only on the backscattering coefficient, ηB, of the non‐normal electron incidence and varies linearly with it. Analytical expressions are given for calculating ĒB/E0 and the backscattering coefficient, which is independent of the backscattering coefficient at normal incidence.
X‐ray fluorescence determination of niobium and tantalum in geological materials
Authors: Chaudhury G. P. Basu , Ganguli C. K. , Sen N.
Published: May 2005

Niobium and tantalum have been determined in gelogical samples by X‐ray fluorescence spectrometry without the determination the remaining elements in the sample by applying a suitable modification of the Traill and Lachance equation.
A modified approach to the quantitative XRF analysis of thick targets
Authors: Orlić I. , Tomić S. , Makjanić J. , Jakšić M. , Valković V.
Published: May 2005

The widely used formalism for quantitative XRF analysis based on the correction of characteristic line intensity for absorption effects is shown to be inadequate when thick samples with low total mass attenuation coefficients are analysed (biological samples, solutions, etc.). The geometry factor is not a constant function of the collimator's shape and dimensions, but it is found that in an analysed matrix it depends on the line energy and penetration depth. An experimental and a theoretical model for the determination of the geometrical correction are proposed and tested on a set of samples. The concentrations obtained are in excellent agreement with the values expected, whereas the model based on the correction of intensities only for absorption effects gives an error of at least 25% for thick samples.
Routine method of X‐ray spectrometric analysis without standards involving only initial instrumental calibration. 1—Theory and derivation of calculation equations
Authors: Wang Yongzhong , Chen Zhimin
Published: May 2005

Using theoretical expressions derived previously, a set of equations for the calculation of characteristic X‐ray fluorescence spectrometric parameters without standards is derived. All effects due to K series spectra of the jth element which can excite the characteristic fluorescent X‐ray of the ith element and all effects due to the instrumentation have been considered. An equation for the calculation of the attenuation factor of the instrument is presented.

The results of experiments show that the accuracy of the equations is good, and in their practical application the geometric configuration of the specimen is generally not required. The specimen can be a fragment, piece or powder, etc., without special preparation requirements.
Energy‐dispersive X‐ray fluorescence analysis of massive sulfides using fundamental influence coefficients
Authors: Johnson Robert G. , Fleming Stanley L.
Published: May 2005

A method for the energy‐dispersive X‐ray fluorescence analysis of Si, S, Fe, Cu, Zn, Pb, Ag, Cd and Sn in massive sulfide samples is described. Samples were prepared as briquettes, and a matrix correction employing inter‐element influence coefficients calculated from fundamental parameters was used. Values calculated in this manner for six international reference materials compare favorably with those found in the literature as well as those determined with other methods.
Determination of arsenic in rocks and ores with a sequential X‐ray spectrometer
Authors: Ward J.
Published: May 2005

The determination of As making use of the Kα net intensity requires subtraction of the overlapping Pb Lα peak. As the interfering intensity cannot be measured directly, a calculated value has to be obtained from measurement at the Pb Lβ line. A mathematical approach was developed which is based on a typical mean value for the ratio between the Pb Lα and Lβ net intensities. Three measurements per sample are required and the routine calibration procedure is set up with three standard samples. Measurements are fed into a computer programmed to calculate both As and Pb concentrations. The programme corrects for matrix effects by means of one of the measurements that is taken at a chosen background point.

The method was devised for fast routine analysis and can be applied to samples of varied composition with the limitation that the As and Pb emission lines are not subjected to significant enhancement. Samples are prepared by grinding the material to a suitable fineness and then pressing it into a tablet. The attainable accuracy and limit of detection for As depend on the Pb level present in each sample.
Evaluation of the main atomic number, absorption and fluorescence correction models in quantitative microanalysis
Authors: Ugarte D. , Castellano G. , Trincaveli J. , Del Giorgio M. , Riveros J. A.
Published: May 2005

The principal LAF correction models have been tested for a set of 471 experimental values from heavy element binary specimens (Z > 12) and another set of 116 determinations for oxides, both compiled by Love et al. New fluorescence correction models have been developed, based on a Gaussian distribution of ionizations. The atomic number, absorption and fluorescence correction models corresponding to this distribution are the best fitting ones.
The Claisse–Quintin and Lachance–Claisse alpha correction algorithms and their modifications. A critical examination
Authors: Tertian R.
Published: May 2005

A slow progress has led us from a reduced formulation (Claisse—Quintin) to a perfected one combining: (1) an advanced knowledge (Tertian and co‐workers, Lachance) of the properties of binary influence coefficients; and (2) Tertian's equation for the resultant third element effect in any multi‐element system. The new algorithm is accurate and compares easily with typical fundamental parameter approaches (Criss and co‐workers) or fundamental coefficient approaches (Broll and Tertian, Rousseau). It suffers from the same reservations as regards possible deviations between theoretical assumptions and experimental reality. A refined experimental study of suitable binary standards should help to reduce these uncertainties.
Deconvolution problems and information theory
Authors: Nuñez J. , Rebollo Neira L. E. , Plastino A. , Bonetto R. D. , Guérin D. M. A. , Alvarez A. G.
Published: May 2005

A method is derived, using information theory and the maximum entropy principle, for treating deconvolution problems. The approach is particularly suitable for the determination of instrumental effects in spectral lines. The technique is illustrated by recourse to numerical examples. A comparison is made with alternative methods. Although realistic situations are restricted to the correction of x‐ray diffraction profiles (instrumental width), the formalism applies for any spectral technique.
Comparison of fundamental parameters programs for quantitative X‐ray fluoréscence spectrometry
Authors: Bilbrey D. B. , Bogart G. R. , Leyden D. E. , Harding A. R.
Published: May 2005

Five readily available fundamental parameters x‐ray spectrometry programs were compared for their performance in a more or less routine laboratory environment. The programs were used to determine a variety of elements in cement, geological samples, low‐alloy steels, nickel alloys and plant material. All data were acquired using energy‐dispersive x‐ray spectrometry. Criteria used in the comparison include accuracy, versatility and ease of use. Performance is given in statistical summaries.
Average L shell fluorescence yields from L shell vacancies in radionuclides
Authors: Sahota H. S. , Singh Rajender , Sidhu N. P. S.
Published: May 2005

A method has been devised to test the correctness of relationships for computing L shell vacancies in radionuclides following electron capture and internal conversions. The average L shell fluorescence yields in eleven elements have been derived from a comparison of computed vacancies and measured subshell intensities. The validity of the relationships derived earlier is confirmed.
Problems of automated qualitative X‐ray fluorescence analysis. 2–Location of maxima and line identification
Authors: Jordanov Ju. , Tsanov Ts. , Stefanov R. , Jordanov N. , Ortner H. M. , Wilhartitz P. , Jenul R.
Published: May 2005

A method is described for the determination of angular positions of maxima in an x‐Ray fluorescence spectrum registered by step scanning. The cases of single and overlapping maxima were investigated. For each maximum the angular interval was determined, containing all lines which may be the cause of its emission.
A new approach to the particle‐size effect correction in the x‐ray fluorescence analysis of multimetallic ore slurries
Authors: Lankosz Marek
Published: May 2005

A method of correcting for particle‐size effects in the XRF analysis of ore slurries is proposed. The use of a calculated heterogeneity factor for correcting the intensity of fluorescent x‐rays from the determined element is suggested. The possibility of using a value of a weight fraction of particles smaller than 75 μm for determining the heterogeneity factors has been studied. The method has been tested experimentally on samples simulating zinc‐lead and copper ore slurries.
Studies on the variation of cell dimensions of mullite with iron oxide and titania additions
Authors: Das P. , Choudhury R.
Published: May 2005

An analysis has been made of Cameron's data on the variation of the cell dimensions of mullite for compositions with additions of more than 1.0% of Fe + Ti for samples crystallizing out of the melt phase. It was observed that, depending on the amount of either iron oxide or titania added, the cell dimensions change with respect to changes in cell volume, exhibiting shrinkage along either the b or c cell edges. Increasing amounts of titania appear to influence the c cell edge in preference to the a and b edges. The overall cell symmetry, however, is preserved with a simultaneous increase in the a cell edge with change in the cell volume.
Quantitative determination of gold in ore using energy‐dispersive XRF spectrometry
Authors: Kasrai M. , Fozoonmayeh L. , Payrovan H.
Published: May 2005

A method is described for the analysis of gold ore in the ppm range using energy‐dispersive XRF spectrometry. Ore is digested in aqua regia and gold is separated by coprecipitation with tellurium, followed by solvent extraction into isobutyl methyl ketone (IBMK). The recovery of gold is better than 98% and the detection limit is 0.1 μg of gold.
Monte carlo simulation of thin‐film X‐ray microanalysis at high energies
Authors: Rosa R. , Armigliato A.
Published: May 2005

A Monte Carlo code previously used in modelling x‐ray emission by incident electrons of several tens of kilo‐electronvolts has been extended up to 300 keV, which is typical of the present medium‐energy transmission electron microscopes. With the aid of a further numerical code, both the thickness and composition of thin self‐supporting films can be simultaneously determined. This code exploits the bootstrap statistical method, which provides a realistic error analysis of the final results from the precision of the experimental data. The potential of the two codes is illustrated through a simulated example of a single self‐supporting film. Such calculations can also be applied to two or more overlying films transparent to an electron beam.
EDXRF Studies on the variation in elemental concentrations of ceramic glazes
Authors: Yap C. T.
Published: May 2005

Energy‐dispersive x‐ray fluorescence was used to study the variations in the elemental concentrations of ceramic glazes. The results show the constancy of the concentrations of Rb, Sr, Y, Zr and Nb and also of the Mn/Co ratio determined at different positions in a piece of porcelain. They also show that during the Qing dynasty, it was common practice to use a different glaze for the base of a piece of porcelain, in contrast to the modern practice of using the same glaze for the whole piece.
Recent measurements of long‐wavelength x‐rays using synthetic multilayers
Authors: Huang T. C. , Fung A. , White R. L.
Published: May 2005

An evaluation of the x‐ray fluorescence analysis of light elements (B, C, N and O) using synthetic multilayers and a conventional x‐ray spectrometer has been conducted. It is shown that effective measurements of long‐wavelength x‐rays can be made by using properly selected synthetic multilayers. For both B and C K radiations the Ni/C (2d = 158.8 Å) multilayer has the highest reflectivities, whereas the V/C (121.8 Å) and the W/Si (55.4 Å) multilayers have the best resolving powers. For N and O K radiations, the W/Si (80.2 and 55.4 Å) multilayers are preferred. The 80.2 and 55.4 Å W/Si multilayers produce the highest intensity and resolving power, respectively. The detection limits of the light elements using the multilayers have also been calculated, and it is shown that levels as low as 0.02% are achievable for the carbon and oxygen analyses using the Ni/C and W/Si multilayers, respectively.
Analysis of trace elements in hair of pregnant women using XRF spectrometry
Authors: Tomić S. , Lakatoš J. , Valković V.
Published: May 2005

It 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.
Determination of manganese in high‐chromium steels by X‐ray fluorescence spectrometry
Authors: Rajeev  , Muralidhar J.
Published: May 2005

The interference of Kβ radiation from chromium in the XRF analysis of manganese at low concentration in high‐Cr steels is discussed and a simple chemical method is suggested for overcoming the problem.
EDXRF and XRD studies on alumina fibre using natural fibre as substrate
Authors: Patel M. , Padhi B. K. , Sastry D. L.
Published: May 2005

The 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

Results 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

A 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

Al 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

An 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

The 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

Quantitative 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

High‐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

Polynomial 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

A 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

Results 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

The 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

A 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

Accurate 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

A 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

A 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.
Determination of trace elements in aluminium with synchrotron radiation‐induced x‐ray fluorescence
Authors: Chevallier P. , Abbas K. , Sainfort P.
Published: May 2005

A systematic study of trace elements in aluminium has been undertaken. Calibration graphs and detection limits were deduced for various excitation energies.
Comparison between two x‐ray analysis software packages
Authors: Boman J. , Isakson J.
Published: May 2005

Different 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

In 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

A 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

A 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

Typical 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

Energy‐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

Energy‐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

Photon‐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.
Absorption correction in electron probe microanalysis
Authors: Gaber M.
Published: May 2005

The 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

To 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

Several 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

Collimated 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

A 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

An 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

The 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.