bluuebunny/crossref_metadata_2025_split huggingface dataset:
Profile analysis of experimental x‐ray fluorescence spectra
Authors: Huang T. C. , Lim G. 
Published: May 2005

AbstractA systematic study has been made of the line shapes of x‐ray fluorescence spectra obtained with a conventional spectrometer using various analysing crystals and experimental conditions. It was found that each component of the K and L spectra can be closely matched by the sum of an asymmetric Gaussian and Lorentzian, namely the pseudo‐Voigt function. Analysis of spectra in the 0.4–3 Å range showed that profile shapes are functions of 2θ, the analysing crystal and the collimating system, but nearly independent of chemical state, specimen thickness and operating voltage. For a fixed analysing crystal and collimator, larger values of 2θ exhibited lower Gaussian content and higher asymmetry. Using an LiF (200) crystal, spectra obtained for 2θ° < 20° were found to be pure Gaussian and symmetric, indicating the dominance of the instrumental effects. As 2θ increased, the Lorentzian component or the spectral effects emerged and the shapes became asymmetric. The analysing crystal has a pronounced effect on the experimental profile shapes. Use of a graphite (002) instead of an LiF (200) crystal yielded profiles three times wider and with twice the Lorentzian content. The differences between PET and LiF crystals were smaller. The accuracy achieved in using the pseudo. Voigt function to describe the experimental XRF spectra demonstrates the convenience and effectiveness of the function in obtaining precise fluorescence intensities, especially in the case of poor counting statistics and/or overlaps.
Cubic spline representation of the two‐variable cumulative distribution functions for coherent and incoherent x‐ray scattering
Authors: Yacout A. M. , Verghese K. , Gardner R. P. 
Published: May 2005

AbstractIn Monte Carlo simulation of energy‐dispersive x‐ray fluorescence analysers, one must account for both x‐ray scattering effects and photoelectric absorption. To access the required random values of differential coherent and incoherent scattering angles, two‐variable cubic spline representations of the appropriate cumulative distribution functions are developed and their use is demonstrated. In this approach the scattering angle is taken to be the dependent variable while the two independent variables are the x‐ray energy and the normalized cross‐sections.Cubic spline coefficients for the elements from sodium to nickel have been obtained for x‐ray energies from 1 to 150 keV for all scattering angles for both coherent and incoherent scattering. Compared with the commonly used method of numerically integrating tabular values of coherent and incoherent cross‐sections to produce a table of values for subsequent interpolation, use of cubic spline representations gives a 90% reduction in storage space and a 25–80% reduction in the amount of computer time required for equal accuracy.
A modified theoretical model for the efficiency calculations of a Si(Li) detector
Authors: Garg M. L. , Singh Jasbir , Verma H. R. , Trehan P. N. 
Published: May 2005

AbstractA radial efficiency correction factor was introduced in the five‐parameter radially dependent model by Cohen to calculate the theoretical efficiency of an Si(Li) detector. The present calculations for the various detectors confirm that the radial dependent factor introduced by Cohen is a geometry‐dependent factor and does not depend on the physical characteristics of the detector. The modified five‐parameter model suggested in this study removes the anomaly between the theoretical calculations and experimental observations.
Surface and near‐surface chemical characterization by low‐energy electron‐induced X‐ray spectrometry (LEEIXS): A review
Authors: Romand M. , Bador R. , Charbonnier M. , Gaillard F. 
Published: May 2005

AbstractVarious experiments show that low‐energy electron‐induced X‐ray spectrometry (LEEIXS), using a gas discharge tube as an efficient and stable electronic excitation source, represents a powerful new technique in many fields of research related to surface and near‐surface chemical characterization of materials. The instrument is a wavelength‐dispersive X‐ray spectrometer capable of high qualitative or quantitative performances in the soft and ultra‐soft region (λ = 0.3—10 nm). LEEIXS applications given in this paper demonstrate how chemical, electrochemical or physical treatments of various substrates modify the solid surface composition.
Excited fluorescence in low‐Z elements by the low‐energy gamma transitions and L X‐rays from a 241‐am XRF source
Authors: Delgado V. , González L. , López A. , Morán P. , Vañó E. 
Published: May 2005

AbstractThe influence of the photons emitted by a 241Am XRF excitation source below 59.6 keV on sample fluorescence production has been analysed. A general method for evaluating the contribution of the various lines from the source in specific equipment configurations is presented. The excitation was performed with 23 elemental targets and the measured experimental intensities were fitted by means of a minimization program which takes into account the most important transition groups observed in the spectrum of the excitation source. The program allows for attenuation of excitation and fluoresced photons in the target. Intensity data for the exciting beam were compared with the theoretical intensities of photons from 237Np, and it was concluded that these values are compatible with the Am and Al thicknesses of the excitation source. Correction factors considering low‐energy transitions were calculated for several elements for both thick and thin targets. The over‐excitation evaluated for Z = 34 reached values ranging between 180% and 550%.
Determination of metals in oil using total reflection X‐ray fluorescence spectrometry
Authors: Bilbrey D. B. , Leland D. J. , Leyden D. E. , Wobrauschek P. , Aiginger H. 
Published: May 2005

AbstractOil was chosen as a new sampl type for total reflection XRF. A thin‐film sample procedure is described which requires minimal sample preparation. This involves first bringing the oil into solution with a volatile solvent, then pipetting microliter amounts on to the reflector substrate followed by evaporation of the solvent. The linear dynamic range was found to extend to at least 5000 ppm. Detection limit measurements show that minute sample quantities are necessary for optimal detection limits of nanogram amounts. A maximum sample loading is required for the best detection limits in ppm. Using an Mo or Cu X‐ray tube, limits were found to be a few ppm or sub‐nanogram amounts. The spectrometer was calibrated by an internal standardization method and the results of determinations on sample solutions were typically within 10% relative accuracy.
Measurement of K X‐ray fluorescence cross‐sections for some elements with 23 ≤ Z ≤ 55 in the energy range 8–60 kev
Authors: Kumar Sudhir , Singh Surinder , Mehta Devinder , Singh Nirmal , Mangal P. C. , Trehan P. N. 
Published: May 2005

AbstractKα and Kβ X‐ray fluorescence cross‐sections were measured for V, Mn, Co, Br, Rb, Mo, In, Sb, I and Cs at nine excitation energies ranging from 8 to 60 keV using energy‐dispersive X‐ray fluorescence spectrometry. The results were in good agreement with the theoretical values calculated using photoionization cross‐sections based on the Hartree‐Fock‐Slater model.
Ice thickness and low‐energy Si(Li) detector efficiency measurements
Authors: Cohen David D. 
Published: May 2005

AbstractA simple technique for measuring the thickness of ice build‐up on the front face of Si(Li) detectors is described. This ice thickness varies with time and significantly modifies the low‐energy efficiency of Si(Li) detectors in the 1–5 keV energy range. We also report on the branching ratios for the ten resolvable neptunium M shell X‐ray lines from thin 241Am α sources.
Problems of automatic qualitative X‐ray fluorescence analysis: Part one
Authors: Jordanov J. U. , Tsanov T. S. , Stefanov R. , Jordanov N. 
Published: May 2005

AbstractThe first three stages of the automatic qualitative X‐ray fluorescence analysis: scanning of the spectrum, smoothing of the spectrum and approximation of the background are described. Considerations about optimal smoothing of the spectrum are presented using the different features of analytical lines and noise. A function well approximating the background intensity in dependence on the wavelength is found, and a method for background construction from the minima in the spectrum is discussed.
Absolute method for determination of metallic film thickness by X‐ray fluorescence
Authors: Vázquez C. , de Leyt D. V. , Riveros J. A. 
Published: May 2005

AbstractAn absolute method for the determination of the thickness of a nickel film on iron has been developed. The mass absorption coefficient of nickel for the effective wavelength has been determined empirically and mathematically. The found values were in agreement. To perform this method only one intensity measurement of the fluorescent substrate emission is required (Fe Kα). The method was tested using iron sheets with different thicknesses of nickel obtained by chemical deposition. Thicknesses between 6 and 25 μm produced relative differences from gravimetric values of 1.8‐1.1%.
Sample preparation method for major‐element analyses of carbonate rocks by X‐ray spectrometry
Authors: King Bi‐Shia , Vivit Davison 
Published: May 2005

AbstractA sample preparation method is described which permits fast and accurate wavelength‐dispersive, x‐ray fluorescence analysis of ten major oxides in carbonate rocks. The sample is first ground into a fine powder, then calcined, its loss‐on‐ignition (LOI) is determined and finally it is fused into a glass disc with lithium tetraborate at 1100°C using a 1:10 sample‐to‐flux ratio. Geological reference standards and synthetic standards are used for calibration. Matrix effects are corrected empirically using Lachance‐Traill correction algorithms. The accuracy and precision of the method were assessed by the analysis of several NBS carbonate reference standards.
Quantitative XRF analysis of surface layers: Influence of primary energy distribution and enhancement
Authors: Rössiger V. 
Published: May 2005

AbstractA theoretical approach to quantitative x‐ray fluorescence analysis of multicomponent surface layers is described. It includes both the determination of the primary energy distribution of the tube and the calculation of the x‐ray intensities according to the fundamental parameter method. The effects of several inaccuracies, such as those from the primary distribution, from the treatment of secondary excitation and from the analytical representation of attenuation cross‐sections, are discussed in detail. Their influence on the XRF intensities was studied theoretically and compared with experimental data for a wide variety of well defined multilayer systems. The final accuracy of the theoretical calculations allows one to dispense with calibration reference standards in practical analytical work.
Loss‐on‐ignition corrections in the XRF analysis of silicate rocks
Authors: King Bi‐Shia , Vivit Davison 
Published: May 2005

AbstractAn empirical method for loss‐on‐ignition (LOI) corrections in XRF analysis is presented. It is based on a polynomial relationship between the disc weight ratio (D/Dz) and the analyte concentration ratio (Ciz/Ci) for a series of synthetic standards with various known LOI contents, where Dz and Ciz are disc weight and analyte concentration, respectively, at zero LOI. The coefficients derived from regression analysis of the relationships are unique to each analyte element, and may be used to adjust the disc weight ratio. The adjust disc weight ratios are than applied to correct the apparent concentration to a standard measurement condition, which is zero LOIThe effectiveness of this LOI correction method was verified experimentally by the analysis of some well characterized geochemical reference samples with various LOI contents and the results were found to be in good agreement with the recommended values.
Precise calibration of sequential x‐ray spectrometers
Authors: Sperling Z. 
Published: May 2005

AbstractSmall differences between actual 2d spacings of analytical crystals and those used for the calculation of 2θ tables generate θ‐dependent deviations of measured 2θ values from tabulated values of up to several tenths of a degree. It is shown that these deviations can be separated into a constant and a tan θ‐proportional component and used for a precise calibration of the spectrometer in terms of the actual value of the 2d spacing of the analytical crystal and of the 2θ dial offset. The reported results were obtained on two instruments, an older manual spectrometer and a newer one operating under computer control.
Enhancement effect as a relative excess absorption
Authors: Kuczumow Andrzej , Holland J. Grenville 
Published: May 2005

AbstractA new approach to problems associated with enhancement effects in XRF analysis, and by analogy to analysis by electron microprobe and PIXE, is discussed. The concept of enhancement as ‘relative excess absorption’ is introduced. This concept allows an arrangement of mass balances in which the concentration of any given element may be derived explicitly from a set of relationships equivalent to fundamental expressions, such as the Lachance–Traill and Tertian equations for monochromatically excited XRF and the Claisse–Quintin equations for polychromatic excitation. In this new approach the values of μk′(λi or Ei) may be derived, and carry the meaning of apparent mass absorption coefficients for absorption and enhancement effects characteristic of any given pair of elements. Finally, some obvious convergences between XRF, electron microprobe and PIXE analyses are emphasized.
Repeated intensity measurements for X‐ray fluorescence analysis of thin samples and evaluation of a scattered line as an internal standard
Authors: Iwatsuki Masaaki , Ito Makoto , Shimizu Hisae , Endo Masashi , Fukasawa Tsutomu 
Published: May 2005

AbstractPeak intensities of Fe Kα and scattered W Lα were repeatedly measured on 10‐μg iron‐impregnated and blank pieces of filter‐paper, repeatedly remounted or as mounted, at their 20 angles reset or as set, by the fixed‐time method at various times. Relative standard deviations (RSDs) of the Fe Kα intensity and Fe Kα/W Lα intensity ratio and the detection limit (DL) of iron were compared among these repeated measurements. With a constant total counting time, subdivision of the total time into a large number was preferable for the trace analysis of impregnated thin samples. Slight variations in the sample mounting had a large effect on the RSD and DL, whereas variation in the angle setting had a negligible effect. The use of the scattered W Lα intensity as an internal standard had no advantage in the trace analysis of thin samples.
Effect of coster–kronig transitions on L3 sub‐shell x‐ray fluorescence cross‐sections
Authors: Rani Anita , Nath N. , Chaturvedi S. N. 
Published: May 2005

AbstractCoster–Kronig processes are radiationless transitions in which an inner‐shell vacancy is transferred from one subshell of an atom to another that is less tightly bound, both belonging to the same principal shell. Experimental measurements were carried out on a few elemental samples to examine the effect of Coster–Kronig transitions on fluorescence cross‐sections for the Lα x‐ray line using 22.6 keV Ag K x‐rays for excitation. Absolute values of Lα cross‐sections were also calculated with incorporation of the enhancement due to the Coster–Kronig effect for the elements in the range 41 ≤ Z ≤ 92 at the same excitation energy. A windowless Si(Li) detector system with an energy resolution of 145 eV at 6.4 keV x‐ray energy was used. Thin‐film samples were employed to minimize the self‐absorption effect. Reasonably good agreement was observed between the expected and measured values.
Microbeam technique for energy‐dispersive x‐ray fluorescence
Authors: Rindby A. , Engström P. , Larsson S. , Stocklassa B. 
Published: May 2005

AbstractBy using the total reflecting properties of x‐rays inside glass capillary tubes, intense fine or microbeams of x‐rays can be obtained. In combination with conventional diffraction x‐ray tubes, microbeams with a diameter of a few micrometres and with an intensity sufficient for trace element analysis can be achieved. The basic physics behind the capillary technique is reviewed and an energy‐dispersive x‐ray fluorescence microbeam spectrometer for trace element analysis is described. Examples of applications of the microbeam spectrometer are given and the future perspectives of the capillary technique are discussed.
Backscattering of 10–35 keV electrons from thick targets at normal incidence
Authors: Del Giorgio M. , Trincavelli J. , Riveros J. A. 
Published: May 2005

AbstractEnergy distributions of backscattered electrons were obtained by Monte Carlo simulations for a wide range of elements for electron beams at normal incidence and with energies Eo between 10 and 35 keV. These spectra were compared with experimental data and with a theoretical expression. An analytical expression was fitted to the simulated data. An expression for the backscattered electron coefficient η as a function of atomic number Z and incident energy Eo was obtained. A model for η and the energy distribution of backscattered electrons for multielement samples is suggested.
EXAFS measurement with laboratory equipment: Problems and their countermeasures
Authors: Okamoto Tokuhiko , Yamashita Seiichi , Yamaguchi Toshio , Wakita Hisanobu 
Published: May 2005

AbstractExperimental techniques for eliminating the characteristic x‐rays emitted from impurities in cathode and anode materials in the vicinity of the x‐ray absorption edge were studied with a laboratory EXAFS spectrometer using a rotating anode. Two methods are proposed for this purpose, a current‐control system and a filter method involving the use of a material that selectively absorbs characteristic x‐rays. The former method was applied to the Co, Ni and Zn K absorption spectra and the latter to a Pd K absorption spectrum, and the results were compared with those obtained from conventional measurements. The change in the nearest neighbour structure of Pd in a Pd‐Al2O3 catalyst accompanied by oxidation or reduction was clarified by EXAFS and XANES measurements with the use of the filter method.
Determination of forms of sulphur in plant material by x‐ray fluorescence spectrometry
Authors: Pinkerton A. , Norrish K. , Randall P. J. 
Published: May 2005

AbstractA method is described for the determination of S6+ (sulphate) and Sc (C—S bonded sulphur) in plant material by x‐ray fluorescence spectrometry which is considerably more simple and rapid than the chemical determinations of the corresponding sulphur forms.
Two simple, practical correction procedures for spectra processing in energy‐dispersive x‐ray spectrometry
Authors: Eggert F. 
Published: May 2005

AbstractProcedures are presented for reducing the complexity of common energy‐dispersive x‐ray emission spectra. The methods are two rapid and simple spectra‐processing tools that eliminate, channel by channel, both the escape effect and all Kβ lines coupled to the corresponding Kα lines. An outline of problems related to the escape‐effect correction and Kβ line stripping is given. Listings of programs in Turbo‐Pascal are presented.
A PIXE data reduction code utilizing an IBM PC
Authors: Hallak A. B. , Al‐Kofahi M. M. , Al‐Juwair H. A. 
Published: May 2005

AbstractUsing a data library of element‐specific x‐ray energies and their relative intensities in PIXE, a computer code named MAXE (material analysis by x‐ray emission) was written for spectrum deconvolution and inspection. Subroutines were included for peak identification, background continuum generation, system calibration, peak deconvolution and peak‐area determination. The background is fitted in parts by an exponential function which allows excellent background generation for any matrix. In addition, combined data collection from the RBS and PIXE set‐ups in the same chamber is possible thoough the code. This allows for double checking of the elemental composition and a wide coverage of the elements that are present in the sample matrix. A performance test of our code compared with a widely used program (AXIL) for PIXE analysis showed good agreement.
Versatile and accurate trace element determinations in iron‐rich and other geological samples using x‐ray fluorescence analysis
Authors: Croudace Ian W. , Gilligan Jon M. 
Published: May 2005

AbstractThe reliable, routine XRF determination of trace elements in iron‐rich geological samples, such as banded iron formations, oolitic ironstones and ferromanganese nodules, has until recently been limited. The scattered radiation method (using Compton scattering), well established in normal silicate rock analysis, was developed for the determination of trace element concentrations in diverse rock compositions. Single calibration lines are used for each trace element and serve to provide data over broad sample compositions, ranging from 0 to 70% Fe2O3. A critical evaluation of the calibration lines obtained and the results of trace analyses of synthetic mixtures showed the method to be readily capable of providing accurate chemical data.
Use of theoretical accurate binary influence coefficients with Tertian's equation in x‐ray fluorescence analysis of silicate rocks in borax glass beads
Authors: Muia L. M. , Van Grieken R. 
Published: May 2005

AbstractA study of the suitability of the Tertian algorithm using new ‘accurate’ binary influence coefficients and a comparison standard for x‐ray fluorescence analysis of geological materials prepared as borax glass beads was performed. The algorithm was found to give satisfactory results for the analysis of four major components in geological materials. Even in the worst case, when there is a factor of 20 difference in the concentration in the specimen and a comparison standard, the algorithm gives results which differ from the true results by a factor of about 2. This makes the algorithm attractive as a diagnostic tool in analyses of unknown specimens and in the identification of appropriate standards. The binary coefficients are easily calculated so that the algorithm can be implemented on a minicomputer.
Study of mean excitation energy and K‐shell effect for electron probe microanalysis
Authors: Brizuela Horacio , Riveros José Alberto 
Published: May 2005

AbstractThe K‐shell correction to stopping power developed by Livingston and Bethe and its influence on electron microprobe analysis are discussed. A comparison among models for the mean excitation energy J given by different workers was made. Two new expressions for J as a function of atomic number Z are suggested for the microanalysis of samples with K‐shell effects: one from stopping power experimental data and the other one from Chu and Powers' theoretical calculations. Livingston and Bethe's K‐shell correction was applied to both new models.
Trends in quantification in XRF
Authors: Vrebos B. A. R. , Kuipéres G. T. J. 
Published: May 2005

AbstractTrends in the areas of analysis of low atomic number elements, routine quantitative analysis, matrix correction methods, qualitative analysis, set up and calibration, data processing and lower limits of detection are given, based on a short overview of the past, and extrapolating to the future.
Compact synchrotron radiation light source covering the soft x‐ray to the ultraviolet spectral region
Authors: Nakabushi Hiromitsu 
Published: May 2005

AbstractThe compact superconducting synchrotron radiation source AURORA is being developed for industrial use, especially for x‐ray lighography. This source can also be used for research purposes. A prototype machine has been constructed to demonstrate the performance and to study various applications. Acceleration and storage of electrons in the ring was recently achieved. A storage current of 20 mA at 650 MeV energy is attained and the beam lifetime is more than 20 h. The half‐integral resonance injection method has been proved to work well. Further improvements are being studied, including that of the performance of the injector.