bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measuring the dead time of an x‐ray spectrometer by means of the first‐ and second‐order reflections method
Authors: Bonetto R. D. , Riveros J. A. 
Published: May 2005

AbstractThe dead time of a Philips PW 1410 x‐ray fluorescence spectrometer with a photon detector has been calculated employing intensities of first‐ and second‐order reflections. The spread of the values obtained can be considered very satisfactory in the light of the experimental difficulties inherent in this method.
A fundamental parameter method for measurement of the thickness of pure element films by an EDX technique with a proportional detector
Authors: Takagi H. , Shima H. , Ui T. , Asada E. 
Published: May 2005

AbstractApplication of the fundamental parameter method to the determination of film thickness by an EDX technique with a proportional detector was performed by considering that x‐rays striking the detector were composed of the following kinds: (1) the analyte line of the film excited directly by the primary beam, (2) the analyte line of the film excited secondarily by scattered or characteristic x‐rays from the substrate and (3) scattered and characteristic x‐rays from the substrate which passed through the film to be analysed. The intensity of all these types were considered theoretically, and the film thickness was evaluated by fitting the theoretical intensity of the x‐rays striking the detector to the experimental intensity, by use of an iteration process. In addition, the accuracy of the theoretical values of intensities excited secondarily was verified by comparison with the experimental values.
Computer method for qualitative wavelength‐dispersive x‐ray fluorescence analysis
Authors: Vila E. , Bermúdez‐Polonio J. , Jiménez‐Seco J. L. 
Published: May 2005

AbstractA computer method for the qualitative analysis of fluorescence spectra recorded with any analysing crystal and using any wavelength‐dispersive x‐ray spectrometer is described. Originally, the programs are designed for an Olivetti P 6066 computer without being on‐line with the spectrometer. These programs may, of course, also be used with slight modifications with higher capacity and on‐line computers, thus making the analysis easier and faster.
Zn Kα/Rb Kβ ratio of Ch'ing, Republic and modern Chinese porcelains
Authors: Yap C. T. , Tang S. M. 
Published: May 2005

Abstract122 pieces of Chinese porcelains from K'ang Hsi to 1982 made in Ching‐te Chen were analysed using energy‐dispersive x‐ray fluorescence with a Cd‐109 exciter. The Zn Kα/RB Kβ ratio was found to be less than about 0.12 ± 0.03 for all pieces made before World War II and greater than about 0.12 ± 0.03 for all pieces made after the War, making it possible to detect modern fake reproductions easily and nondestructively.
Energy dependence of photon‐induced Kα and Kβ x‐ray fluorescence cross‐sections for some elements with 20 ≤ Z ≤ 56
Authors: Garg M. L. , Mehta Devinder , Kumar Sudhir , Mangal P. C. , Trehan P. N. 
Published: May 2005

AbstractKα and Kβ x‐ray fluorescence cross‐sections were measured at ten excitation energies ranging from 5.96 to 59.54 keV for elements with 20 ≤ Z ≤ 56 and the experimental results were compared with the theoretical values. Fairly good agreement was observed within the uncertainties of the determinations. This is the first time that measurements have been made for ten elements at a number of excitation energies and Kβ XRF cross‐sections are also reported for the first time.
Shift of the centroid of the Co Kα peak of Co3O4 converted from CoCO3 by various calcination parameters
Authors: Rosales P. A. , Carías O. , Labrecque J. J. 
Published: May 2005

AbstractThe calcination of CoCO3 in air results in Co3O4 with particle sizes depending on the heating temperature: the lower the temperature, the smaller is the particle size. It was previously reported that the centroid of the Co Kα peak shifted greatly (>500 eV) when the product (Co3O4) was formed by different calcination temperatures between 200 and 700°C. In the work, attempts were made to reproduce these results by using not only variable temperature but also variable time, and determined the centroid with a high‐resolution Si(Li) detector rather than a scintillation counter. The results showed the shifts to be about ten times smaller than previously reported. The shift of the Co Kα peak centroid has been estimated to be less than 30 eV.
Particle size effects in the X‐ray fluorescence analysis of monolayer samples
Authors: Krasnopolskaya N. N. , Volkov V. F. 
Published: May 2005

AbstractA set of particulate monolayer samples with a δ‐distribution of particle sizes has been produced on Lawsan membrane filters by means of a cascade impactor. The accuracy of a proposed equation for characteristic x‐ray intensity from particulate monolayers of various chemical and granular compositions has been experimentally confirmed. x‐ray spectra of Fe and PbTiO3 powders have been examined following excitation by monochromatic photons.
Heterogeneity effects in direct XRF analysis of traces of heavy metals preconcentrated on polyurethane foam sorbents
Authors: Török Szabina , Braun Tibor , Van Dyck Peter , van Grieken René 
Published: May 2005

AbstractTrace amounts of heavy metals were preconcentrated on discs of polyurethane (PU) foam loaded with ammonium diethyldithiocarbamate (DDTC), to increase the sensitivity of XRF. Since the diameter of the cavities in the open‐cell PU foams reaches 30–300 μm, considerable heterogeneity effects might occur, which could reduce the accuracy of the method. The possible systematic error introduced by considering the sample to be homogeneous is calculated using the Berry et al. model. The calculations show that the underestimation of the absorption correction factor when considering the sample as being homogeneous is less than 2% for high‐Z elements when the sample thickness is at least 2 mm. The detection limits are also around the minima for this thickness.
Portable X‐ray fluorescence analyser with increased precision by using the method of balanced filters
Authors: Vatai E. , Andó L. 
Published: May 2005

AbstractAn increase of an order of magnitude in the precision of the balanced filters method is achieved by using a low‐power x‐ray tube and measuring the ionization current, without increasing the measurement time. A simultaneous change of excitation and detection is essential: the measurement of the ionization current makes possible a dead‐time free detection of the high intensities excited by the x‐ray tube, and leads to a decrease in the statistical error. The standard deviations obtained with a portable analyser utilizing this method in the determination of the Cr and Mn contents of low‐alloy steels in the concentration range 0–1.5% are 0.02 and 0.03%, respectively.
Sample homogeneity in energy‐dispersive XRF trace metal analysis
Authors: Rastegar B. , Jundt F. , Gallmann A. , Rastegar F. , Leroy M. J. F. 
Published: May 2005

AbstractThe x‐ray fluorescence analysis of trace elements in aqueous solutions requires adequate sample preparation techniques. Aqueous solutions, taken from the environment, often contain chlorides or carbonates, which are likely to produce small crystalline conglomerates in the dried specimen. The use of emulsifiers in the process of specimen preparation was investigated and their advantages demonstrated.
X‐ray K absorption spectra of copper in its soaps and their liquid crystalline solutions in benzene
Authors: Nigam A. N. , Rajput O. P. , Shrivastava B. D. 
Published: May 2005

AbstractThe K absorption edge of copper in myristate, palmitate, stearate and oleate soaps and their benzene solutions have been studied. The solutions show pronounced EXAFS and seem to be liquid crystalline.
A simple absorption correction for electron probe X‐ray microanalysis of bulk samples
Authors: Markowicz A. , Storms H. , van Grieken R. 
Published: May 2005

AbstractA simple procedure is proposed for the calculation of the absorption correction factor in electron‐probe x‐ray microanalysis. It is based on the concept of an effective depth of x‐ray production, assuming a rectangular depth distribution function for x‐ray generation. This effective x‐ray production depth is expressed as a fraction of the x‐ray excitation depth given by Whelan's expression. Adequate values for this fraction are presented. Two versions are considered. In the first the effective x‐ray production is a function of both the characteristic x‐ray energy and the atomic numbers of the matrix elements, whereas in the second one, which is indicated for routine use, the energy dependence is neglected. Calculations pointed to satisfactory results, even for low x‐ray energies and high overvoltages.
Quantitative electron probe microanalysis of carbon in binary carbides. I—principles and procedures
Authors: Bastin G. F. , Heijligers H. J. M. 
Published: May 2005

AbstractIntroductory investigations performed in order to make quantitative electron‐probe microanalysis of very light elements such as boron, carbon, nitrogen or oxygen possible are described. The practical problems encountered in this kind of work are discussed in detail and, where possible, solutions are proposed. It is shown that with very light elements such as carbon it is no longer permitted to measure x‐ray intensities at the position of the maximum of the emission peak as the shape of the carbon Kα peak is subject to strong alterations, depending on the type of chemical bond involved. As a consequence, integral measurements have to be performed and it is shown that errors of 30–50% can easily be made if this is neglected. The lengthy procedures, connected with integral intensity measurements, can be shortened considerably by the introduction of area/peak factors, which, by definition, represent the ratio between the correct area (integral) and the peak intensity ratio. The accurate determination of such factors for 13 binary carbides is described. This set of factors will permit future measurements simply on the peak; multiplication of the peak intensity ratio by the appropriate area/peak factors will then yield the correct integral intensity ratios.
Energy dependence of the, sensitivity of sequential x‐ray spectrometers obtained from multi‐element standards
Authors: Freiburg C. , Reichert W. , Solomah A. G. 
Published: May 2005

AbstractThe sensitivity of an x‐ray spectrometer as a function of the x‐ray energy is defined as S = I/c = f(E), where S is the sensitivity, I is the count rate per second, c is the concentration and E is the x‐ray energy of the analyte line. Knowledge of its exact shape is needed to calibrate the spectrometer and to analyse minute amounts in different matrices. It can be determined experimentally using multi‐element standards with low concentrations of the standard element, with careful selection of the standard and the matrix compounds. The homogeneous mixtures of powder pellets were obtained by ball‐milling with the addition of lubricating agents. The grain sizes were controlled under a light microscope.Two empirical equations describing the sensitivity are proposed:
equation image
where S is the sensitivity, A, B1, D and F are numerical coefficients, θ is the Bragg angle of the analysing crystal, E0 is the energy of maximum sensitivity (E0 = 17.6 kV) and the exponent p is equal to 0.5. The ranges of validity of Eqns (1) and (2) are discussed for a PW 1410 (Cr side‐window tube) and an S/MAX (Rh front‐window tube) spectrometer. An application using Eqn (1) is given for the determination of the element concentrations from Nb to Ni in certified soil standards.
Ageing of glass disks. A Monte Carlo simulation of the related XRF intensities
Authors: Helsen J. A. , Vrebos B. A. R. 
Published: May 2005

AbstractThe order of magnitude of change of intensities of Ca and Si Kα and La Lα lines in a homogeneous solid solution with respect to a microsegregated sample is estimated by Monte Carlo simulation. The overall composition of the (hypothetical) melt is Li2CO3La2O3 (19:1) with 5, 10 or 15% of CaSiO3. Calcium metasilicate was assumed to segregate from the flux in particles with radii of 1, 5, 10 or 15 μm. Intensity changes comparable to those observed in real samples are obtained.
The amorphous character and particle size distributions of powders produced with the Micronizing Mill for quantitative x‐ray powder diffractometry
Authors: O'Connor B. H. , Chang W‐J. 
Published: May 2005

AbstractThe rapid rise in the popularity of the McCrone Micronizing Mill for sample preparation in routine quantitative analytical x‐ray powder diffractometry (XRPD) has led to the present examination of material obtained with the device and a comparison with material produced by the widely used Tema Mill. Specimens of α‐quartz, prepared for a range of milling times under wet‐ and dry‐grinding conditions, were assessed according to their particle size distributions and XRPD integrated intensities. Particle size distributions were measured using a sedimentation technique. Changes in XRPD integrated intensity with milling treatment have been used to derive amorphous content indices representing the change in estimated intensity attributed to milling. The results show that the McCrone Mill can produce XRPD specimens of α‐quartz for assay work which adequately satisfy particle size criteria. Powders obtained by wet‐milling with the McCrone device are more acceptable for XRPD work than those prepared by dry‐milling, and both are clearly superior to powders produced with the Tema Mill under the dry‐grinding conditions considered in this study.
Quantitative x‐ray fluorescence analysis. Theory and practice of the fundamental coefficient method
Authors: Broll N. 
Published: May 2005

AbstractThe object of this paper is to outline the principle of the fundamental influence coefficient method and emphasize its utilization for the accurate x‐ray fluorescence analysis of compact or diluted specimens.For any given composition, effective coefficients, as defined by Tertian's identities, can be derived from the calculation of the theoretical fluorescence intensities, as used in the fundamental parameter approach. The importance of a careful selection of theoretical data is underlined. These include the fundamental parameters, i.e. essentially the mass absorption coefficients and the excitation factors, and the instrumental characteristics, namely the spectral intensity distribution of the x‐ray tube and the geometric factor of the spectrometer. All of these data are still under investigation and the accuracy of their determination is being assessed. The effective coefficients are inserted in a comparison standard algorithm, a practice which compensates for the residual uncertainties affecting some of the parameters. In fact, and in terms of concentration ranges, the compensation limits are fairly large and can be extended, if necessary, by recurrence procedures. A special correction algorithm, similar to the basic one, but based on ‘modified’ coefficients, is used for the analysis of diluted specimens. A suitable computer program and its accessories are defined and their use is illustrated by a variety of practical applications including the analysis of stainless steels, high‐temperature alloys, non‐ferrous alloys (bronzes) and, as an example of fused specimens, cement. The characteristic of the fundamental coefficient method is that it combines the theoretical exactness of the fundamental parameter approach with the flexibility of the usual Lachance‐Traill formulation, thus allowing any given analytical problem, whether complex or comparatively simple, to be studied and solved in agreement with the actual degree of difficulty and the accuracy required.
Optimization of geometry for x‐ray analysis of rare earth materials
Authors: Lal Madan , Choudhury R. K. , Agrawal R. M. 
Published: May 2005

AbstractA method of sample excitation is proposed for obtaining good sensitivity and detection limits for rare earth elements (57 ≤ Z ≤ 69) by energy‐dispersive X‐ray fluorescence analysis using a 241Am radioisotope source. Detection limits of about 100—300 ng for most of the elements using a thin multi‐element sample on a Mylar backing are obtained for a counting time of 1 h with a 100 mCi source. The configuration employed is a close‐coupled collimated side source geometry in which the sample is mounted at 45° to the plane of the detector. This geometry was found to be superior to the commonly used wide annular geometry in terms of the detection limits obtained for the analysis of rare earth elements. A comparative study of the performance of different source geometries using both Mylar‐ and cellulose‐based samples is described.
Theoretical assessment of the coefficients ϕ(0) and γ0 of the Gaussian ϕ(ρz) curves
Authors: Saa J. H. Tirira , Riveros J. A. 
Published: May 2005

AbstractNew analytical expressions for the surface ionization, ϕ(0), and the amplitude of the ionization distribution, ϕ(ρz), in the surface γ0, are derived which take into account physical reality. Values of these parameters are obtained using these expressions and compared with previous models and experimental determinations. The proposed expressions show very good agreement with measured values.
Die Nutzung externer Linienz‐zu Untergrundverhältnisse in der quantitativen energiedispersiven Elektronenstrahl‐Mikroanalyse. (Use of external peak‐to‐background ratios in quantitative energy‐dispersive electron probe microanalysis)
Authors: Heckel J. , Jugelt P. 
Published: May 2005

AbstractA method is described for the quantitative analysis of bulk specimens without standards by using external peak‐to‐background ratios in energy‐dispersive electron probe microanalysis. The advantages of this method are discussed in comparison with other correction procedures and the efficiency is demonstrated by means of the quantitative analysis of eight binary specimens and two steel specimens. An algorithm is described for the quantitative analysis of a bulk specimen with a rough surface.
Kβ2/Kβ1,3 X‐ray intensity ratios of arsenic, selenium and bromine in various chemical states (chemical state analyses of As, Se and Br by X‐ray method. 4)
Authors: Iwatsuki Masaaki , Fukasawa Tsutomu 
Published: May 2005

AbstractA dilution method of correction for a strong self‐absorption effect on the measurements of Kβ2/Kβ1,3 intensity ratios of arsenic, selenium and bromine is described. The intrinsic intensity ratios obtained by the method are given and discussed for these elements in various states in powder and solution samples. The results are as follows: (1) the intensity ratio increases in the order As < Se < Br; (2) any element with a negative oxidation number gives a considerably larger intensity ratio than the same element with a positive or zero oxidation number; (3) the atoms surrounded by stronger electron donors give a larger intensity ratio; (4) a solution sample of a substance gives a larger intensity ratio than its powder sample, except for arsenic compounds; (5) a dilute solution sample below 0.1 M gives a larger intensity ratio than its concentrated solution sample, and its ratio is little affected by coexisting ions.
A new measurement of the Lα1,2 X‐ray emission spectrum of Zn and the K emission bands of Zn and Ga
Authors: Leiro J. A. 
Published: May 2005

AbstractA measurement of the Lα1,2 X‐ray emission spectrum of Zn is described. The experimental 3d band seems to be slightly narrower than the calculated band provided that the lifetime broadening of the 2p level and the instrumental function are taken into account. The high‐energy satellites of the Zn Lα1,2 line are discussed and the relative intensities of the features considered. Also, the K emission bands of Zn and Ga have been measured. The quadrupole lines have been identified in these spectra and the relative intensities estimated.
Description of low‐energy peak distortion observed in X‐ray spectrometry with Si(Li) detectors
Authors: Heckel J. , Scholz W. 
Published: May 2005

AbstractA simple model is developed to describe the shape and intensity of the low‐energy peak distortion measured with Si(Li) detectors in X‐RAY SPECTROMETRY. Based on this model, a method is outlined for correcting the distortion channel by channel, which drastically reduces the expense of the deconvolution of the pulse‐height spectra measured in energy‐dispersive X‐ray emission analysis with Si(Li) detectors.
Elemental analysis using electron beam‐induced K X‐rays
Authors: Pape A. , Sens J. C. , Georgiadis A. 
Published: May 2005

AbstractRepresentative production cross‐sections for bremsstrahlung, which constitutes an unavoidable spectral background in an X‐ray analysis using electron beam excitation, have been calculated as a function of target and angle for incident electrons in the energy range 0.2—10 MeV. These values, used in conjunction with the corresponding K X‐ray production cross‐sections and non‐fundamental experimental variables particular to each laboratory (detector resolution and ambient background), determine the feasibility of a K X‐ray analysis by direct electron beam excitation, and permit the evaluation of an ideal detection limit.
Optimization of geometry for radioisotope excited X‐ray fluorescence spectrometry
Authors: Dos Santos J. M. F. , Conde C. A. N. 
Published: May 2005

AbstractThe source‐sample‐detector efficiency for the recessed source geometry was evaluated, using Monte Carlo techniques, for a variety of samples and sources and found to be superior to that for other geometries in energy‐dispersive X‐ray fluorescence analysis. The samples considered were those with atomic number in the range 14—44 and the radioactive sources were 55Fe, 244Cm and 109Cd. Efficiencies well above 1% can be achieved for the recessed source geometry and samples with atomic number above 20. The values attainable are around four times larger than those for the annular source geometry.
Uncertainties in mass absorption coefficients in fundamental parameter X‐ray fluorescence analysis
Authors: Vrebos B. A. R. , Pella P. A. 
Published: May 2005

AbstractVarious compilations of mass absorption coefficients are currently used in fundamental parameter computer programs for correction of inter‐element effects in quantitative x‐ray fluorescence analysis. Statistically significant differences in results of analysis were observed for certain sample types when three commonly used compilations were compared, especially when only pure element standards were used for calibration. When type standards combined with a second degree polynomial fit to the standards are used for calibration. When type standards combined with a second degree polynomial fit to the standards are used for calibration, differences between compilations become negligible as determined from the analysis results.
Yield calibration stability of a Si(Li) X‐ray detector system in a PIXE experimental setup over a period of 3 years in the 0.9–9.5 keV photon energy range
Authors: Bombelka E. , Richter F.‐W. 
Published: May 2005

AbstractRelative experimental detector yields and yield ratios measured on mono‐ and bi‐element standard samples from 1984 to 1987 are presented. Above 3 keV photon energy the yields show good long‐term reproducibility. For example, the spread of 38 single yield measurements on the Au Lα x‐ray line is 1.5%. No temporary changes are observed. In contrast, the measured yields in the photon energy range from 3 keV down to 0.9 keV show distinct temporary changes. At the beginning and end of the measurement period the detector was routinely warmed and re‐pumped in order to ensure a good vacuum in the detector housing. At these times the yields show jumps, which increase with decreasing photon energy up to 20% for Na K x‐rays with 1.041 keV photon energy. Between the detector regenerations the yields show a decreasing tendency with time. This behaviour is attributed to the photon absorption in a varying ice layer on the liquid nitrogen‐cooled Si(Li) detector crystal. After the first regeneration the ice layer thickness was reduced by 0.7 μm. Between the regenerations the ice layer growth rate is estimated to be 0.004 μm per month corresponding to a 0.15 μm ice layer after 35 months. The second regeneration reduced the ice layer by a further 0.22 μm.