bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated matrix‐correction of line ratios in energy‐dispersive x‐ray fluorescence spectrum deconvolution
Authors: Van Dyck P. , Van Grieken R. 
Published: May 2005

AbstractMost computer XRF‐spectrum deconvolution routines make use of fixed intensity ratios for the lines from one element. The magnitude of the error that fixed ratios imply has been quantitatively evaluated for samples with a varible thickness or matrix. A procedure for routinely adapting the line ratios according to the matrix effect in every sample (by making use of the matrix information present in the scatter peaks) enhances the accuracy of the spectrum evaluation.
Quantitative light element analysis using an energy dispersive detector. 1–Dead time and the low‐energy spectrum
Authors: Bloomfield D. J. , Love G. , Scott V. D. 
Published: May 2005

AbstractA study of the low‐energy region (below 1. 5 keV) of energy dispersive x‐ray spectra has been carried out. Firstly, because some counting systems do not provide a reliable dead time correction, a new method of dealing with the problem is given. Next, the effects of different positioning of the energy discriminator within the analyser circuitry are discussed with reference to the consequences for light element analysis. Electronic noise counts can present a problem for analysis of x‐rays of less than 300 eV and a straightforward method for noise removal is described. Finally, an unexpected artifact in the spectrum below 500 eV is identified; its size is related to the total number of counts in the spectrum and a practical method of dealing with it is demonstrated. Once the above factors have been taken into account a low energy spectrum is produced, consisting solely of characteristic x‐ray lines and a true continuum background.
X‐ray fluorescence analysis of iron ore concentrates
Authors: Turmel S. , Samson C. 
Published: May 2005

AbstractAn x‐ray method has been developed for the routine determination of many elements in iron ore concentrates. The combination of a glass disk technique, the α‐coefficient method of correction and solution of linear equations yields a rapid and accurate method. The determination of eight elements was performed on different certified iron ore concentrates.
X‐ray mapping using a new coded irradiation technique
Authors: Gurker N. 
Published: May 2005

AbstractX‐ray imaging for physical analysis (elemental mapping) using ‘point’‐scanning methods suffers from long scanning times and low signal‐to‐noise ratios owing to the absence of proper focusing elements. A possible solution to this problem is to increase the interaction area (volume) for a single data acquisition step (‘line’ and ‘area’ scanning) and the use of suitable data to image transformation methods. Since in the past line scanning has been used (image reconstruction from projections), a new scanning concept (mask scanning, ‘coded irradiation’) is now introduced, which is related to coded aperture techniques. The principles, computer simulations and first experimental results are presented.
The problem of irradiation and detection angles in quantitative XRF analysis
Authors: Avaldi L. , Bui C. , Milazzo M. 
Published: May 2005

AbstractThe problem of the dependence of the XRF yield on the irradiation and detection angles and on the sample volume has been critically reviewed. A simple procedure, which accounts for the effect of the sample finite thickness, is given. Applications to the analysis of metal alloys and of organic matrix standards are also reported.
Determination of barium, lanthanum, cerium and neodymium in lateritic materials by various energy‐dispersive X‐ray fluorescence techniques and neutron activation analysis
Authors: Labrecque J. J. , Beusen J. M. , van Grieken R. E. 
Published: May 2005

AbstractA comparison of four methods for the determination of barium, lanthanum, cerium and neodymium in lateritic materials from Brazil is presented. Three of the methods were based on x‐ray fluorescence (XRF) spectroscopy: two by radioisotope excitation (Co‐57 and Am‐241) and one by secondary target XRF (a molybdenum target with a tungsten anode). The other method was based on neutron activation analysis employing both a Ge(Li) coaxial detector and a high‐purity germanium detector.The results from these four methods were similar for lanthanum, cerium and neodymium, but for barium at low concentrations (<500 ppm) the neutron activation and the secondary target XRF methods were not suitable. Data on the precision and accuracy of these methods using a series of standard reference rocks are given. The advantages and limitations of each of these methods with respect to the analysis of lateritic materials are discussed.
X‐ray K‐absorption edge of Co and Cu in their 2‐thiopyrrole‐1,2‐dicarboximide‐ and N‐carbamoylpyrrole‐2‐thiocarboxamide‐based complexes
Authors: Rajput O. P. , Nigam A. N. , Padalia B. D. 
Published: May 2005

AbstractThe complexes of Co and Cu with 2‐thiopyrrole‐1,2‐dicarboximide and N‐carbamoylpyrrole‐2‐thiocarboxyamide were studied by recording the x‐ray K‐absorption edge and the extended structure. The nature of the metal to ligand chemical bond has been interpreted in terms of the effective nuclear charge.
Critical comparison of sample preparation methods for major and trace element determinations using X‐ray fluorescence
Authors: Bower Nathan W. , Valentine Greg 
Published: May 2005

AbstractTen geochemical reference rocks were used to evaluate the preparation of glass disks and pressed powder samples and counting errors in XRF analyses. Disks prepared with and without heavy element doping at various dilutions with lithium tetraborate demonstrated that all of the methods were limited by preparation errors and that they would give comparable precisions for the 10 major and 12 trace elements determined. However, simplicity of preparation, precision of analysis and total analysis times favored 10:1 or 3:1 dilutions without doping over the doped or pressed powder methods.
Thin‐film thickness calculation to maximize X‐ray fluorescence intensity in transmission arrangements
Authors: Fernández J. E. , Mainardi R. T. 
Published: May 2005

AbstractEquations were obtained from physical theory to express the fluorescence intensity emitted by a sample in terms of the geometrical parameters of a source–sample–detector cylindrical symmetry arrangement. These equations allow the calculation of the optimum sizes of samples in XRF. The thickness required to maximize the detected fluorescence intensity, in terms of the value of the remaining physical and geometrical parameters, was determined. A thin sample in transmission geometry was considered, where excitation is produced by an isotropic monoenergetic x‐ray source. The sizes of the detector and source are such that they are considered to be dimensionless compared with the sample. These approximations do not affect the validity of the results.
Determination of sulfur content by x‐ray fluorescence in samples containing a single sulfide phase
Authors: Pasitschniak A. 
Published: May 2005

AbstractSulfur analysis by XRF cannot, as yet, be carried out concurrently with analyses of major elements. As a result, several alternative means of analysing for sulfur by XRF have been devised. One such analytical method, suitable for analysing sulfur in rocks containing one sulfide‐bearing phase, is presented here. The accuracy and precision of this method, at the 95% confidence level, are 9.8% and 4.4%, respectively.
Fluorescence cross‐sections for L shell x‐ray lines
Authors: Bhan Chander , Chaturvedi S. N. , Nath N. 
Published: May 2005

AbstractAbsolute 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

AbstractA 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

AbstractIntercomparison 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

AbstractThe 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

AbstractUsing 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

AbstractNiobium 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

AbstractThe 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

AbstractUsing 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

AbstractA 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

AbstractThe 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

AbstractThe 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

AbstractA 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

AbstractA 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

AbstractFive 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

AbstractA 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

AbstractA 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

AbstractA 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

AbstractAn 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

AbstractA 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

AbstractA 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

AbstractEnergy‐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

AbstractAn 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.