bluuebunny/crossref_metadata_2025_split huggingface dataset:
An iterative method for determining background intensities used in XRF calibration lines for flux‐fusion silicate rock analysis
Authors: Parker R. J. 
Published: May 2005

AbstractIn major element rock analysis using XRF and fused samples and standards, the construction of standard calibration lines is facilitated by the accurate knowledge of the background intensities for the elements analyed. As an alternative to measuring the background ‘off peak’ or on blanks, an iterative technique is proposed. This technique is based on repeatedly incrementing the background value until the best calibration line has been found. The quality of the calibration line is evaluated in terms of the average relative and average absolute errors. Comparative data, presented for calibration lines constructed from (1) backgrounds measured from blanks and (2) backgrounds determined by iterationm, show that the iterative technique produces superior calibrations. The analytical techniques have been tested by analysing international rock standards as unknown samples.
Appearance of the gold MIV, V absorption edges in the background of energy‐dispersive X‐ray spectra
Authors: Brombach J. D. 
Published: May 2005

AbstractBackground calculations for low‐energy energy‐dispersive X‐ray spectra from biological ice, when attempting quantitative microanalysis, must take into account the anomalous gold MIV, V absorption edges at 2220 and 2307 eV. The discrepancy between the mass absorption coefficient from generalized tables used in the electron microprobe analysis and those values actually observed is pointed out. The spectral shape of the Au MIV, V edges is discussed in terms of the photoionization cross‐section of the 3d‐subshell. Theoretical and experimental results are comparted with the table values. A formula used in the calculation of spectrometer efficiency and spectral background is given.
Experimental determination of XRE interelement correction coefficients from binary systems using a modified lachance‐traill approach
Authors: Difruscoa R. , Dick J. G. , Wan C. C. 
Published: May 2005

AbstractA modified Lanchance–Trail approach is presented for the empirical determination of XRF interelement correction coefficients through experimentation. An exhaustive study of binary systems involving aqueous solution media has been used to obtain the true effects of one element on another, with the additional possibility of taking into consideration other effects which become apparent, such as enhancement effects. The method is described in detail, with several examples provided to show the effectiveness of the procedure. A total of approximately 200 coefficients have been investigated and are discussed.
Pitfalls in linear and non‐linear profile‐fitting procedures for resolving severely overlapped peaks
Authors: Statham Peter J. 
Published: May 2005

AbstractLinear and non‐linear least‐squares profile‐fitting procedures are compared in their ability to resolve severely overlapping peaks in X‐ray spectra. With linear methods, errors due to inaccuracies in peak position and width are likely to be greater than statistical errors for a spectrom with 500 K counts unless the spectrometer can maintain a temporal and count are stability of 1 eV or better. While non‐linear, iterative, procedures can accomodate changes in position and width of peaks, they are difficult to analyse therotically so simulations have been designed to examine performance. Examples are given where, despite exact knowledge of peak width and separation, the best fit in the ‘chi‐square’ sense corresponds to peak heights which are totally incorrect. Estimates of statistical error are virtually meaningless when convergence occurs to such inapprooriate minima but rather precise starting values for the unknown parameters are required to ensure convergence to a relistic solution. In view of these potential difficulties and the lack of any theoritical analysis of the instabilties introduced by statistical noise, errors in background subtraction or unsuitable parameterization of peak models, it is felt that linear method are preferable. Thus, high spectrometer stability still seems to be unavoidable if one is to exploit the availabler statistical accuracy in an X‐ray spectrum.
Quantitative X‐ray spectrometric analyses with a cold cathode tube attachment
Authors: Mills J. C. , Belcher C. B. 
Published: May 2005

AbstractA CGR cold cathode tube for X‐ray anlysis of very light elements has been attached to a sequential Siemens XRF spectrometer. Economic consideraions justify a rapid changeover attachment rather than the purchase of a separate spectrometer which can be applied to a few elements. The essential conceppts developed for successful integration of the attachment with the spectrometer are described. An automic activated alumina trap system to remove backstreaming oil vapours was incorporated with the existing vacuum logic. The current stabilization circuit of the generator was redesigned in order to acheive quantitative analyses. The developed attachment has competitive applicability to the quantitative analyses of magnesium and lighter elements. For magnesium the cold cathode tube achieves a large deduction in both matrix absorption effects and high order spectral interferences when compared with a typical chromium tube.
Routine performance of a matrix‐correction free X‐ray fluorescence spectrometric method for rock analysis
Authors: Govindaraju K. , Montanari R. 
Published: May 2005

AbstractIn modern geochemical laboratoriesX‐tay fluorescence spectrometry (XRFS) is a highly favoured analytical technique particularly when the need for geochemical data is relatively important. The analytical procedures currently employed involve XRFS analysis of lithium borate fused glass disc of rock samples, followed by computer generated mathematical corrections for the usual matrix effects. A significantly different procedure, free from mathematical matrix effect corrections, is presented here. After the lithium borate fusion step, the ground fusion product is dissolved by thorough mixing with an aqueous suspension, of a strong acid cation exchange resin in H+ form. During the caution exchange dissolution, the cautions originally present in the sample are transfered quantitatively and uniformly to the resin pahse. The oven‐dried resin heads coated as a thin film on a strip of adhesive paper are analysed. The routine performance of the procedure is illustrated with the data accumulated on six major elements (Al, Fe, Ca, Mg, K and Ti) in five international rock reference samples during a period of one academic year. The main feature of this analytical method is the production of high quality geochemical data without any need for mathematical corrections.
Praktische Fehlertheorie der Röntgenspektrometrie
Authors: Plesch R. 
Published: May 2005

AbstractDie Qualität eines Analysenverfahrens ist in erster Linie durch seinen Fehler gekennzeichnet, aus dem sich als weiters wichtige Kenngrössen die Unterscheidungsgrenze und die Nachweisgrenze ableiten lassen. Alle diese Fehlergrössen werden unter den Bedingungen der analytischen Praxis behandelt. Es wird ferner gezeigt, dass die vielfach gemachten idealisierten Annahmen für die gennten Fehlergrö zu Werten führen, die praktisch nicht erreichbar und daher fü die Praxis ohne Bedeutung sind.
X‐ray microanalytical senstivity and spatial resolution in scanning transmission electron microscopes
Authors: Faulkner R. G. , Norgård K. 
Published: May 2005

AbstractExperimental and theoretical studies of fine electron beam interactions with film specimens are described. It is shown that a Monte Carlo‐based method for plotting electron trajectories can give good indications of both X‐ray spatial resoultion and sensitivity as experienced during X‐ray microanalysis in scanning transmission electron microscopes (STEM). The main operational parameters considered are aperture and lens settings, beam accelerating voltage and specimen thickness. Based on theroretically and experimentally determined data, as set of conditions for optimum X‐ray detection sensitivity and X‐ray spatial resoultion for nickel and aluminium are presented. It is shown that little advantage is gained by performing X‐ray microanalysis at beam accelerating voltages greater than 100kV. Also the necessity to condense the beam spot size to less than 100 Å is relatively unimportant from the viewpoint of improving X‐ray spatial resolution in STEM.
The direct measurement of Ga in binary PuGa alloys using X‐ray spectrometic techniques
Authors: Wallace P. L. , Homser P. K. , Walden J. C. , Haugen W. L. 
Published: May 2005

AbstractThree X‐ray spectrometric procedures have been developed to directly measure the Ga content in binary PuGa alloys. In one procedure en energy‐dispersive spectrometer is used; in the other two a wavelengh‐dispersive spectrometer is used. Certified reference alloys with known Ga content have been produced, and simple procedures to handle them safely have been developed. We have constructed an energy‐dispersive spectrometer system for analyzing Pu‐containing materials and charactrerized the low energy gamma‐ray spectrum of Pu.
Corrections for scattering in X‐ray fluorescence experiments
Authors: Keith H. D. , Loomis T. C. 
Published: May 2005

AbstractCoherent and incoherent scattering processes are commonly ignored, or at best estimated only crudely, in X‐ray fluorescence experimently designed either to measure physical constants or to effect nondestructive chemical analysis of mixtures and alloys. The influence of this scattering is of second order, but is nevertheless large enough (generally 2–5%) to overshadow inherent errors in experimental measurement. In this paper, we develop a formalsim for calculating scattering corrections applicable to experiments involving either thin polycrystalline or amorphus samples studied in transmission or thick samples of a similar kind examined using reflection geometry. Our principal approximations are physical; we assume (i) that crystal line structure and texture in the sample serve merely to modulate the angular distribution of coherent scattering can be ignored. Mathermatical development of the model is essentially exact. Adequacy of approxination (i) is supported by previously published experimental and theoretical work; as for approximation (ii), we have found that results do not depend crucially upon the particular angular distribution function assumed for scattering. We believe, at a conservative estimate, that overll errors in our scattering corrections are in almost all cases of interest less than 25%; data to which they are applied, therefore are, potentially accrate to better than 0.5–1.25% Three important effects have to be considered: (a) the generation of fluorescence radiation which has been scattered within the sample,(b)the scattering of fluorescent radiation away from the acceptance aperture of lthe detector, and (c)the scattering of fluorescent radiation into this aperture. In our formalism, only (a)and (c)need be calculated explicityly. Corrections are expressed simply as products of quotients σ/μ with certain enhancement terms (μ being a total attenuation constant and σ an attenuation constant for scattering). In transmission geometry, the enhancement terms are complicated functions of transmission factors for exciting and fluorescent radiations only and, in reflection geometry, they are simpler functions of angles specified by the experimental arrangement used and the total attenuation constants for exciting and fluorescent radiations. It turns out in many cases that (c) above is the predominant effect and, commonly, the positive contribution to measured fluorescent intensity made by scatting into the detector outweighs substantially the negative contribution made by scattering out of the detector. Results are also expressed in simple graphical form in terms of effective attenuation constants for exciting and fluorescent radiations; in this form they are readily available for use by the reader without the necessity for further calculation. Surprisingly, effective attenuation constants are generally smaller, often consideraby smaller, than constants representing photoelectric absorption alone.
Quantitative energy‐dispersive X‐ray analysis of transition elements in aluminium alloys, at concentrations of less than 1%
Authors: Mora R. 
Published: May 2005

AbstractA SEM/EDAX/NOVA‐2 system, with quantitative analysis program EDIT/EP7–ZAF auto, has been used for analysing the transition elements in aluminium alloys. Handling the sample carefully and choosing optimum operating conditions, has enabled us to determine the concentrations below 1% of these elements, with a percentage error less than ±10%, in most elements, except in Zn, due to interferences in its Kα line with the Cu Kβ.
Escape peak losses in Si(Li) detectors
Authors: Sioshansi P. , Lodhi A. S. 
Published: May 2005

AbstractEscape peak losses in Si(Li) detectors for X‐rays in the energy range 2.3–14.2 keV are measured and compared with calculations for normal incidence geometry. The importance of the results for multi‐elemental X‐ray emission analysis is pointed out.
A fundamental parameter method for analysis of alloys by isotope‐excited X‐ray fluorescence
Authors: Kis‐Varga M. 
Published: May 2005

AbstractA new fundamental parameter method applied to energy dispersive X‐ray spectrometry is presented. Am‐241 and I‐125 radioisotope sources were used for excitation. The method is applied to copper–zinc–lead ternary and copper–zinc–lead–tin quaternary alloys and to high‐alloy steel specimens. It is also tested using data given in the literature. The measurements and calculations were performed on‐line by a program running in a 16K, 12 bit minicomputer interfaced to a multichannel analyser. The results were compared with wet chemical analysis.
Empirical method of matrix effect elimination for samples of ‘intermediate’ thickness in EDXRF analysis
Authors: Hołyńska B. , Markowicz A. 
Published: May 2005

AbstractA method of elimination of absorption matrix effects in samples of ‘intermediate’ thickness, based on the use of measurements of the intensities of fluorescent X‐rays of all determined elements and the intensity of Compton back‐scattered radiation, is described. An empirical correction equation proposed in this paper has been checked experimentally using the samples obtained by precipitation of several elements from water solution by sodium diethyldithiocarbamate (NaDDTC). The accuracy of determinations of Cr, Fe, Zn and Pb varies from 1 to 18% (1 s.d.) for mass per unit area from 2000 to 60 μg cm−2, respectively.
X‐Ray spectrometric analysis by fusion methods. A simple procedure for determining effective influence coefficients
Authors: Tertian R. 
Published: May 2005

AbstractA convenient modification of the so‐called self‐consistent calibration method results in a simple, flexible, coherent procedure for complete analysis of any multicomponent system by means of fusion methods. With low dilution techniques, the influence coefficients obtained allow accurate analysis around a typical standard composition, i.e. within restricted concentration ranges, as often occurs in industrial applications. Resorting to higher dilution rates allows one to extend validity ranges at will, according to one's purpose, but at the cost of a lower sensitivity.
Utilisation du Rayonnement Primaire Diffusé par l'Echantillon pour une Détermination Rapide et Précise des Eléments Traces dans les Roches
Authors: Vié le Sage R. , Quisefit J. P. , de la Bâtie R. Dejean , Faucherre J. 
Published: May 2005

AbstractL'association des techniques de Feather et Willis d'une part, Bougault et al. d'autre part permet de développer une méthode simple et efficace de détermination des éléments traces dans les roches. Le facteur de correction matricielle ainsi que le niveau du fond vrai sont déduits de la diffusion du specimen, mesurée d'après l'intensité d'un pic Compton (ou à défaut de celle d'un fond libre d'interférences), et introduits dans une équation unique du type Bougault qui délivre la concentration de l'élément trace. On décrit les bases théoriques et expérimentales de cette méthode, de même qu'une application typique à la détermination de Ni, Zn, Rb, Sr, Zr et Nb dans une série de roches étalons.
X‐Ray K‐absorption edge of bromine in some cobalt complexes
Authors: Kumar A. , Nigam A. N. 
Published: May 2005

AbstractA method for photographic recording of the X‐ray K‐absorption edge of bromine has been developed in which the effect of the photographic emulsion's bromine is nullified. Using this method the Br K‐absorption edge in some complexes containing bromine were recorded with a view to studying the effect of chemical coordination. The effect of the second coordination sphere on the absorption edge of an ion in the first coordination sphere, in a complex compound, has been investigated.
Trace analysis of estuarine brown algae by energy‐dispersive X‐ray fluorescence
Authors: Sauter L. , van der Ben D. , Van Grieken R. 
Published: May 2005

AbstractBrown algae, which are good indicators for estuarine metal pollution, can advantageously be analysed by energy‐dispersive X‐ray fluorescence. The use of thin film samples and samples of intermediate thickness has several advantages over the conventional thick pellet procedure. A quite homogeneous thin target is prepared by suspending 15 mg of dried and ground seaweed powder in bi‐distilled water and evaporating the slurry on a 10 cm2 Mylar foil held in a Teflon ring. The effective sample weight in the beam is calculated by a procedure based on the scatter peaks in the spectrum. Sensitivities are typically in the 2–15 ppm range. The coefficient of variation per analysis averaged over ten elements amounts to 10%. The natural concentration variation in seaweed specimens at one location is 13%. Samples from locations in the more polluted western Scheldt estuary yield significantly higher values for several elements, relative to the eastern Scheldt sites. Possible trace element variations between the top and base of plants, and between different seaweed specimens and sampling seasons, are discussed.
Quantitative volumetric determination of gamma‐2 content in dental amalgam by electron microprobe analysis
Authors: Bryant R. W. , Moran K. J. 
Published: May 2005

AbstractA method has been developed, using an automated electron microprobe, to determine quantitatively from the uncorrected X‐ray data the volume percentage of one phase (Sn–Hg or γ2 phase) in a three‐phase amalgam. The mean γ2 content determined by this technique was compared with results obtained from an optical image analysis of backscattered electron (BSE) images for this amalgam. The technique offers several distinct advantages over previously described methods. It produces easily interpretable data in a numerical and pictorial form, allowing ready comparison between different amalgams. It is free of operator intervention to discriminate phases, and offers the prospect of being a reliable method of determining the γ2 content in amalgams possessing smaller percentages of this phase.
Visual CRO display of pulse height distribution including discriminator setting for a single channel X‐ray analyser
Authors: Shaw S. E. 
Published: May 2005

AbstractAn outline for a simple pulse spectroscope which attaches to a standard laboratory CRO is presented. The peak amplitude (voltage) of each pulse from the linear amplifier of a single channel X‐ray analyser is stored for the duration of one oscilloscope trace. For each amplifier pulse, input from the discriminator is tested and if there is coincidence of pulses the oscilloscope beam is blanked for approximately the first 2 cm of its traverse across the screen. Repetition of pulses forms a pulse height distribution with a rectangular dark area marking the position of the discriminator window.
An electronic modification of an automatic x‐ray fluorescence spectrometer with sample loader to increase the flexibility of the measurement sequence
Authors: Smith T. K. 
Published: May 2005

AbstractThe Philips PW 1450/00 or /10 automatic hardware‐programmed X‐ray spectrometer, when used in conjunction with the PW 1466 60 position sample loader, permits measurement of both standard and unknown using the same channel only when the ratio mode is selected. Further, a standard must be measured for every unknown. An electronic modification is described which overcomes both of these restrictions.
A new system for on‐line x‐ray topography
Authors: Komyak N. I. , Lutsau V. G. , Efanov V. P. , Ivanov S. A. 
Published: May 2005

AbstractA new system for on‐line X‐ray topography is described, in which relative motions of separate assemblies are completely eliminated. The main elements of the system are a low‐power raster‐type X‐ray source with a transmission target and a multi‐capillary collimator. It takes about 2.5–3 min to produce a topograph of silicon single‐crystal (20 × 20 × 0.3mm) when the radiation source power is only 10W.
Optimization of trace analysis by pixe: Angular dependence of the background continuum
Authors: Renan M. J. 
Published: May 2005

AbstractIn charged particle induced X‐ray emission studies, the characteristic X‐rays are superimposed on a continuous background of electromagnetic radiation. This background is a significant source of uncertainty when charged particle induced X‐ray emission is used for analytical purposes. It is demonstrated that the angular distribution of secondary electron bremsstrahlung exhibits significant structure and may be exploited to improve the detection limits attainable with this method. For low‐energy continuum X‐rays, good agreement is obtained with predictions of the relativistic retardation model. Deviations at higher photon energies are attributed to Compton scattered γ‐rays. Finally, suggestions are made regarding optimum energy and angle selections for direct application of particle induced X‐ray emission as an analytical technique, especially when biological samples are investigated.
The computer control of an electron probe microanalyser using camac and coral‐66
Authors: Swindells N. 
Published: May 2005

AbstractA computer control system for an electron probe microanalyser has been designed using CORAL‐66, a high level compiler language, for the control program and CAMAC modules for the instrument interface. The consequences of the choices made in the design are discussed. The performance of the system was measured by comparing the results from carrying out typical operations by hand and by computer control. The results showed an improvement in precision for general operation and analysis, a reduction in the time for analysis and an improvement in operator performance from using the control system.
An in‐depth study of energy‐dispersive x‐ray spectra
Authors: Van Espen P. , Nullens H. , Adams F. 
Published: May 2005

AbstractA detailed study of energy‐dispersive X‐ray spectra is undertaken. Considerable attention is given to a method for a systematic and accurate description of the K and L spectra; a digital correction for the peak profile is evaluated. The following second order effects and spectral artefacts are investigated: radiative Auger transitions, spectral background components, Raman scattering of X‐rays, silicon escape, fluorescence of the detector materials, and sum peaks.
Eine empirische Methode zur Korrektur des Einflusses der Korngröße bei der Röntgenfluoreszenzanalyse von gepulverten Glasproben und anderen Einphasensystemen
Authors: Dümecke Gerhard 
Published: May 2005

AbstractEs wird gezeigt, daß die in der Literatur beschriebenen einfachen Modellezur Korrektur des Korngrößeneinflusses für die quantitative Röntgenfluoreszenzanalyse von Elementen mit niedriger Ordnungszahl (⩽ 20) in gepreßten Pulverproben nicht ausreichen. Auf der Basis eines empirischen Korrekturvorschlages ist es jedoch möglich, ein mit einem Bindemittel verpreßtes Pulver ohne Kenntnis seiner mittleren Korngröße mit einer für die Praxis ausreichenden Genauigkeit zu analysieren. Es werden die zur Analysenberechnung notwendigen Voraussetzungen beschrieben und die verwendeten mathematischen Formeln am Beispiel eines Glaspulvers erläutert.