bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of mass absorption coefficients from inelastically scattered X‐radiation for specimens of less than ‘infinite thickness’
Authors: Kieser R. , Mulligan T. J. 
Published: May 2005

AbstractAn equation is developed which describes the X‐ray scatter radiation from specimens of any thickness. This equation suggests that a specimen's mass absorption coefficient can be determined from its inelastically scattered X‐radiation not only when the specimen is ‘infinitely thick’ but also when it is of ‘intermediate thickness’. Measurements have been carried out with a standard energy‐dispersive X‐ray spectrometer on specimens of ‘intermediate thickness’. Good agreement is obtained between the mass absorption coefficients that are calculated from the scattered radiation and those obtained on the basis of tabulated mass absorption coefficients for the elements.
Ion‐implaned reference standards for the analysis of surface impurities by X‐ray fluorescence spectrometry
Authors: Gries W. H. , Wybenga F. T. 
Published: May 2005

AbstractX‐ray fluorescence spectrometry is capable of the quantitative determination of impurities in and on solid surfaces in concentrations of fractional atomic monolayers. This capability could not be exploited to any large extent in the past due to the lack of suitable standard reference materials. By means of quantitative ion implantation, however, such standards can now be manufactured. They are described and formulae are derived for correcting the fluorescent signal for attenuation due to depth distribution of the impurities as well as for interelement excitation in matrices of higher atomic number than the impurity.
Estimation of the chemical composition of precipitated phase by the electron beam microanalytical technique
Authors: Chatterji S. , Thaulow N. 
Published: May 2005

AbstractThe problem of estimating the chemical composition of small particles of a phase in a matrix of another occurs in a number of fields. The introduction of electron beam microanalytical techniques has made it possible to analyse a volume of 10μm3. In spite of this advancement the chemical composition of the particles themselves is difficult to determine. This difficulty arises from uncertainty as to the full containment of the analysed volume by the particle being analysed. In this paper a statistical approach to establish the chemical composition of the particles themselves has been proposed. This approach is particularly useful when the particles and the matrix have a common element. Two examples are given, one with components of known compositions and another with a component of an unknown composition.
Radiometric diameter concept and exact intensities for spherical particles in x‐ray fluorescence analysis
Authors: Markowicz A. , Van Dyck P. , Van Grieken R. 
Published: May 2005

AbstractIn X‐ray fluorescence analysis the concept of radiometric diameter, d, is often introduced in considerations of the fluorescent intensity from a particulate sample. It represents the mean geometric path of the X‐rays through one particle and is usually simply taken to be equal to the volume‐to‐area ratio of the particle. The effective radiometric path is, however, itself dependent on geometry and absorption effects. Rigorous calculations of the fluorescent intensity from a particle in the π and π/2 geometries were carried out to evaluate the errors involved. It appears that, for π geometry, the discrepancy between these exact results and the intensity calculated via the use of d does not exceed 5.2%. For the π/2 geometry, the errors are much larger and can amount to 50% in realistic cases of X‐ray fluorescence analysis. These conclusions are also applicable to monolayers. The effective radiometric diameter approaches d only when absorption effects become negligible, but is smaller in other cases.
X‐ray K absorption studies on some 1,10 phenanthroline‐based cobalt complexes
Authors: Kumar A. , Nigam A. N. , Shrivastava B. D. 
Published: May 2005

AbstractThe X‐ray K absorption edges of Co in some 1,10 phenanthroline‐based complexes of cobalt have been recorded. The results have been discussed qualitatively in terms of the effective nuclear charge on the central metal atom and the nature of the ligand.
Multilayer X‐ray spectrometry in the 20–80 Å region: A molecular orbital analysis of CO and CO2 in the gas and solid states
Authors: Perera R. C. C. , Henke B. L. 
Published: May 2005

AbstractOptimized multilayer X‐ray spectrometry, using lead myristate and lead stearate analyzers (2d values of 80 and 100 Å) has been applied to the measurement of the O‐‐Kα and the C‐‐Kα spectral bands from CO and CO2 in the gas and solid phases. The LII, III spectra were also measured for argon in the gas and solid states under similar conditions in order to identify and to minimize any non‐molecular components in the CO and CO2 spectra. These molecular orbital data have been related to those obtained with X‐ray and ultraviolet photoelectron spectroscopy and grating X‐ray spectroscopy. The consistency of the results of these complementary measurements is excellent. The ionization energies for the C and O 1s levels have been determined to be 295.4 and 542.0 eV for CO and 296.8 and 540.3 eV for CO2. The MO data have also been compared with that predicted from the symmetry, strength and binding energy of the molecular orbital spectral components as calculated using the currently available computational models, CNDO/2, MINDO/3, MNDO, extended Hückel and ab initio. The molecular orbital calculated results for these organic compounds, CO and CO2, are not in as good agreement with the experimental data as previously demonstrated for molecular orbital spectra measured for C‐‐Kα and the LII, III bands of Cl, S and P for both organic and inorganic compounds.
The influence of tube voltage rectification in X‐ray fluorescence analysis without standards
Authors: Mantler M. 
Published: May 2005

AbstractThe spectral photon distribution from X‐ray tubes operated at constant potential is compared to the distribution resulting from self rectification circuits. Kramers' equation is modified by calculating the average values of the photon flux during one period of voltage fluctuation and the results are used to transform Gilfrich and Birks' experimental tube spectra to those expected from a half‐wave rectification circuit. The effect of using both constant potential and sine wave potential, as well as constant potential with overlaid sine wave ripple, is discussed. Results are shown by using experimental data from Ag‐Au‐Cu alloys and ‘no standard’ methods (data evaluation without reference specimens).
Quantitative X‐ray fluorescence analysis of thin films using LAMA‐2
Authors: Huang T. C. 
Published: May 2005

AbstractAn improved version of the LAMA program for the quantitative analysis of composition and mass thickness of thin film materials by X‐ray fluorescence (XRF) has been developed. The divergence and slow convergence problems occasionally experienced with the LAMA‐1 program have been eliminated by using the linear approximation method and the algorithm of simultaneous refinement of composition and thickness to greatly increase its capability and performance. A study of over a hundred simulated thin films showed that the LAMA‐2 program converged much faster than LAMA‐1 and gave better accuracy. The efficiency of the program has been improved to the point where it is feasible to operate on a minicomputer.
Measurement of K X‐ray fluorescence cross‐sections
Authors: Bhan Chander , Chaturvedi S. N. , Nath N. 
Published: May 2005

AbstractAbsolute values of K X‐ray fluorescence (XRF) cross‐sections have been calculated for elements 11 ⩽ Z ⩽ 69 at three excitation energies corresponding to Mn, Ag and Te K X‐rays from 55Fe, 109Cd and 125I radioisotopes respectively and the fourth energy corresponding to the 59.60 keV γ‐ray from 241Am. Measurements were also made for these cross‐sections for ten elements with 18 ⩽ Z ⩽ 48 at two excitation energies from 109Cd and 125I radioisotopes. The measured values are compared with those obtained from theoretical considerations and a good agreement is found.
Quantitative determination of the various forms of aluminium in steels by X‐ray fluorescence spectrometry
Authors: Grimaldi R. , Paris V. , Mariani E. 
Published: May 2005

AbstractThe aluminium content in steels is particularly important in the improvement of the yield ratio, ageing and magnetic properties, ductility (for marking sheets) and also in the primary metallurgy (continuous casting). From the metallurgist's viewpoint it is important to determine the soluble aluminium content only (i.e. AIN and Al solid solution) and the way this affects some of the mechanical properties. Conventional analysis is time consuming and cannot be employed on‐line therefore it would be useful to employ instrumental analysis. Several approaches have been investigated in the past using emission spectroscopy but this was found to be too complicated and expensive. A new method, described here, uses an X‐ray emission technique which yields good results and can be carried out on a commercially available X‐ray spectrometer without other facilities.
An improved method of x‐ray fluorescence analysis of chrome containing refractories
Authors: Banerjee Subrata , Olsen Ben G. , Hess Melvin K. 
Published: May 2005

AbstractAn improved x‐ray fluorescence method has been developed for the analysis of chrome containing refractory materials (raw materials, in process and final products). It involves the fusion of the powdered samples with a mixture of sodium hexametaphosphate and lithium metaborate in the presence of lanthanum oxide into a glass disc followed by polishing of the disc before exposure to the x‐rays. Three British standards, two South African Standards and one NBS Standard were used for standardizing the method. SiO2, Fe2O3, Al2O3, CaO MgO and Cr2O3 were used in the standardization because these compounds constitute the majority of the materials under analysis. Linear regression analysis of the data showed that all the lines were linear, the coefficient of determination being equal or close to 1.00 with a mean error of less than ±3.5%, excepting CaO which had a mean error of ±8.6% because of its low concentration and the larger variance in its standard value.
Quantitative determination of argon in sputtered films by wavelength‐dispersive electron probe microanalysis
Authors: Willich P. , Obertop D. 
Published: May 2005

AbstractA method is described for the calibration of Ar Kα counting rates, measured using crystal spectrometers equipped with Ar‐flow proportional counters. Linear extrapolation from overvoltage corrected x‐ray yields of the elements with Kα x‐ray energies lower than those of the ArK absorption edge gives an accurate description of the experimental Ar Kα intensity ratios from counters operated at different values of gas pressure. Results of all‐element film analyses provided by a matrix correction procedure, ZAF, indicate an accuracy better than 5% relative for the determination of Ar concentrations ranging from 0.1 to 10 wt%.
Analysis of finely divided metal particles formed in montmorillonite by scanning electron microscopy
Authors: Patel M. 
Published: May 2005

AbstractFinely divided metal particles, formed in the interlayer space of montmorillonite, have been identified by a x‐ray microprobe technique and their dimensions measured by scanning electron microscopy. The dimensions of Ni0 and Cu0 obtained on reduction of the respective metal ions by H2 have been shown to be ∼ 100 Å.
A modified background‐ratio method for x‐ray fluorescence analysis of soil and plant materials
Authors: Livingstone L. G. 
Published: May 2005

AbstractThe isolated atom model of x‐ray scatter has been used to develop a new analytical strategy for internal standardization in x‐ray fluorescence spectrometry. The method defines quantitatively by how much and within what limitations various background‐ratio calibration techniques can improve results for particular elements in specific materials. The analytical strategy is based on a modified peak to background ratio equation, where the background intensity is raised by an exponent T. The variable T combines as special cases all existing analytical strategies which use scattered x‐rays, together with the basic linear calibration where T=0. Variation in T was evaluated using extensive computer processing of matrix data for typical soil and plant materials. It was found that T varied with analyte, scatter wavelength and the matrix component contributing to the mass absorption error. Most existing methods using a background‐ratio technique are shown to be improved by using a value of T other than the previously assumed unity or zero.
The complete spectral response for EDXRF systems—calculation by Monte Carlo and analysis applications. 2—heterogeneous samples
Authors: Doster Joseph M. , Gardner Robin P. 
Published: May 2005

AbstractThe Monte Carlo model for predicting the complete spectral response from homogeneous samples has been extended to heterogeneous samples which may be considered to be spherical particles suspended in a homogeneous matrix. The spherical particles may have any distribution of size and spatial position as specified input. The particle compositions are either: Model 1‐a homogeneous mixture of all the sample elements present or Model 2‐a single pure element appropriately chosen at random from those present. These two sample compositions should represent extremes of the matrix interferences encountered in practice and should, therefore, bound the x‐ray and source scattering spectral responses observed. The sample Monte Carlo results reported here for both heterogeneous models approach the limiting values predicted by the homogeneous model when used for decreasingly small particle sizes and generally exhibit a smooth relationship with particle size. Although comparisons with two sets of experimental results are not entirely satisfactory, the general trends are properly predicted. It is concluded that the models are accurate within our present capability of testing them (at present we only have available two particle spatial distributions for packing fractions of 0.4 and 0.6, both for particles of uniform size).
Modifications of the HEX program for fast automatic resolution of PIXE‐spectra
Authors: Johansson Gerd I. 
Published: May 2005

AbstractThe computer program ‘HEX’ for resolving PIXE‐spectra has been modified. By irradiating standard foils, the escape peak ratios for x‐ray peaks in the energy interval 3.3‐10.6 keV have been measured. The results have been compared with theoretical calculations and experimental results of other research groups. The escape peaks have been included in the computer code. Pile‐up peaks in the x‐ray spectrum are also fitted by the modified computer program. This procedure is independent of the count rate and the pile‐up interval. In addition, an effective routine for rejecting small x‐ray peaks has been developed.
The influence of the fluorescence volume on the observed yield in energy dispersive XRF analysis
Authors: Weber Anders 
Published: May 2005

AbstractIt is shown that when a narrow x‐ray beam is used in energy dispersive fluorescence analysis of thick, low‐Z samples large deviations from the predictions of the commonly used fundamental parameter model occur. A simple method by which the effects can be studied empirically is described. An approximate model allowing a direct calculation of the effécts is introduced. The validity of the model has been confirmed experimentally.
An x‐ray spectrometer with a position‐sensitive wire detector (PSD)
Authors: Ebel H. , Mantler M. , Gurker N. , Wernisch J. 
Published: May 2005

AbstractA new crystal‐type x‐ray spectrometer is described, which employs a position‐sensitive detector for simultaneous radiation detection in a certain energy range given by the spectrometer design. The main specifications are (a) better energy resolution and (b) longer data collection times compared with an energy‐dispersive spectrometer.
The effect of elastically scattered protons on the energy resolution of x‐ray detectors in PIXE measurements
Authors: Mingay D. W. 
Published: May 2005

AbstractExtensive use has been made of particle‐induced x‐ray emission (PIXE) analysis over the past several years. The optimization of its detection sensitivity calls for the judicious selection of several parameters including, inter alia, the beam energy used and the x‐ray window thickness. Thin windows are required in order to detect the light elements whose x‐ray energies are so low that they are heavily attenuated by any absorber material between the target and the detector. The choice of beam energy is dependant on the respective x‐ray production cross‐sections for elements of interest, the related background generated, as well as the associated beam energy degradation in the targets. These considerations often lead to a state where protons, elastically scattered from the target, have sufficient energy to penetrate the window and enter the x‐ray detector. The extent to which such protons and their related secondary electron production affect the energy spectrum resolution of intrinsic germanium and Si(Li) x‐ray detectors is demonstrated for a proton beam energy range from 2.1 to 3.5 MeV with a window thickness equivalent to the range of a 2.5 MeV proton.
The surface geometrical structure effect in x‐ray fluorescence analysis of metallic samples
Authors: Stankiewicz Wiesław , Fudal Andrzej , Wójtowicz Mirosława 
Published: May 2005

AbstractThe results of investigations into the effect of geometrical surface structure in x‐ray fluorescence analysis of Cu‐Ni alloy are presented. The experimental materials were samples of spectrometric standard quality, in which surfaces were especially prepared by grinding and polishing. The surface state was estimated qualitatively, using a scanning electron microscope, and quantitatively, using a profilograph, by the determination of the roughness parameters Ra and Rz. The relationships between the roughness parameters and Cu, Ni and Si fluorescent radiation intensities, as well as the scattered radiation from the x‐ray tube anode element were established. The optimum range of the surface state for a given alloy has been defined.
A detailed evaluation of counting losses of detectors in wavelength‐dispersion x‐ray spectroscopy
Authors: Banerjee Prabuddha 
Published: May 2005

AbstractThe exponential equation R0 = R · eR0τdescribes the counting losses in wavelength‐dispersive x‐ray spectroscopic (WDF) detectors up to very high counting rates. The correction error can be considerably lower than 1% for a true counting rate of 7 · 105s−1. The dead time constant τ has however to be determined very accurately for this. Methods of determining τ with the desired accuracy are also described. And finally, a formula for correcting for dead time losses for two detectors in series, where each detector has a different dead time, is deduced and verified by experiment. Here again, one can calculate the true counting rate with an accuracy of 1% at a true counting rate of about 7 · 105 s−1.
X‐ray spectroscopic studies of copper compounds and complexes in aqueous solution and polycrystalline form
Authors: Koul P. N. , Padalia B. D. 
Published: May 2005

AbstractK‐absorption edge‐shifts of copper in CuCl22H2O CuSo45H2O, Cu(NO3)23H2O, Cu(en)3Cl2, Cu(en)3SO4 and Cu(en)3(NO3)2 in aqueous solutions as well as in polycrystalline form were measured using the x‐ray absorption spectroscopic technique. Effective charge on copper ions are estimated using the method of Gianturco and Coulson. The results of the present study reveal interesting results regarding the nature of chemical bonding. An attempt is made to interpret the results in the light of the available data on these samples.
Comparison of some ambient aerosol samplers in combination with PIXE analysis
Authors: Lannefors H. , Carlsson L.‐E. 
Published: May 2005

AbstractPIXE (particle induced x‐ray emission) analysis of aerosols has been applied to four different samplers to determine sample thickness corrections, detection limits and required sampling times in different environments. The samplers (two total filter samplers, a two stage filter sampler and a cascade impactor) were used with filters made by Ghia, Millipore, Nucleopore and backings of polystyrene film, respectively. The calculations were based on the accumulation mode aerosol (particles in the 0.05–2μm diameter range) composition. Sampling times (resulting in detection limits 10 times lower than assumed aerosol concentrations) ranged from a quarter of an hour in urban, to a quarter of a day in rural and to two weeks in remote environments. These sampling times are calculated with the requirement that at least one element representing each of the following sources was detected: fossil fuel combustion (S, V and Ni), leaded petrol combustion (Br and Pb) and general industrial activities (Cr, Cu and Zn). Generally the two stage filter sampler employed with Nuclepore filters yielded the highest time resolution when specific flow rate, thickness and substrate impurities were taken into consideration. Thickness corrections based on a proton energy of 2.55 MeV and typical ambient urban and rural aerosol matrices show that elements of low atomic number such as P, S and Cl, where the x‐ray self absorption effect is most important, require a 10–20% correction with a uniform deposit thickness of about 0.5 mg cm−2 and a non‐nuniform (conical) deposit thickness of about 1 mg cm−2. For elements of higher atomic number than vanadium (K x‐rays) the proton energy loss correction dominates. Sampling times resulting in the above mentioned deposit thicknesses were shortest for the cascade impactor while the Millipore and Nuclepore filter samplers were least critical in this respect.
The direct addition of Fe‐55 into the sample for low Z elemental analysis by x‐ray emission spectroscopy
Authors: Labrecque J. J. , de Benzo Z. A. , Rosales P. A. , Preiss I. L. 
Published: May 2005

AbstractA new radioisotope excited x‐ray fluorescence (XRF) technique which employs source‐samples has been applied for the determination of low Z elements in geological materials. The source‐samples is prepared by directly inserting about 100 μCi of the radioisotope (Fe‐55) into about 10–20 mg of the sample in its holder and placing this directly on the face of the detector window. The precision (relative total standard deviation) of this technique for K2O%, CaO% and TiO2% is about 4% and is compared to conventional radioisotope excited XRF. Finally, the accuracy of this technique is shown by the analysis of five geological reference materials as well as compared to conventional radioisotope excited XRF.
K x‐ray production cross‐sections of Ag, Sn and Te by 32–80 MeV 32S ions
Authors: Bǎdicǎ T. , Ciortea C. , Petrovici A. , Popescu I. , Osipenko B. P. 
Published: May 2005

AbstractK x‐ray production cross‐sections of Ag, Sn and Te by 32‐80 MeV 32S ions have been measured. The dependence of target K x‐ray yields on the target thickness was found to be negligible in the S (64 MeV) + Ag collision system. The experimental data are compared with some theoretical predictions.
Consideration of an enhancement effect simplified expression in limiting cases in x‐ray fluorescence analysis
Authors: Kuczumow Andrzej 
Published: May 2005

AbstractThe problem of a simplified expression for the enhancement term of correction equations in XRF analysis was treated using the example of binaries. Attention was paid to up‐to‐date propositions of a solution to that problem and new cases of solutions were considered. Some common elements of these solutions were found and on the basis of a fundamental expression of enhancement effects a more general equation is given.