bluuebunny/crossref_metadata_2025_split huggingface dataset:
X-Ray Fluorescence Analysis of Multi-Layer Thin Films
Authors: Huang T. C. , Parrish W. 
Published: March 2019

AbstractThe characterization of multi-layer thin films by X-ray fluorescence using the fundamental parameter method and the LAMA-III program is described. Analyses of a double-layer FeMn/NiFe and two triple-layer NiFe/Cu/Cr and Cr/Cu/NiFe specimens show that the complex inter-layer absorption and secondary fluorescence effects were properly corrected. The compositions and thicknesses of all layers agreed to ±2% with corresponding single-layer films, a precisian comparable with bulk and single-layer thin film analyses.
A Universal Data Base Approach For Quantitative WDXRF Analysis With General Purpose Data Acquisition Algorithms
Authors: Rokosz M. J. , Artz B. E. 
Published: March 2019

AbstractAcquisition of new x—ray fluorescence (XRF) hardware or a data reduction computer can be a particularly frustrating experience for analysts who depend upon programs not supplied by the XRF spectrometer manufacturer. Computerized data collection and reduction pragrams generated for a particular spectrameter/computer system can become virtually useless when a significant part af the spectrometer/computer system is replaced. The problem is compounded in a research environment where many different kinds of samples are encountered and many unique analysis programs developed.The potential magnitude of this problem was recently demonstrated at the Ford Motor Company Scientific Research Laboratory when the thirteen year old computer-contolled XRF analysis system was replaced by a new state-of-the-art spectrometer/computer system.
The Recessed Source Geometry for Source Excited X-Ray Fluorescence Analysis
Authors: Conde C. A. N. , dos Santos J. M. F. 
Published: March 2019

AbstractDifferent geometries are considered for source excited energy-dispersive X-ray fluorescence (EDXRF) analysis Systems, including the recessed source geometry introduced in the present work. The calculated physical excitation-detection efficiencies, for the side (or annular), central, receded and recessed source geometries are presented as a function of the target to source distance, for Ca, K, S and Si targets excited with a Fe-55 XBF-3 X-ray source and xenon filled gas proportional scintillation counters. The last two geometries present in gênerai the highest efficiencies. The recessed source geometry présent the best performance with peak efficiencies a factor of 3.3 better than those for the standard side or annular source geometries.
Contamination of Silicate Rock Samples due to Crushing and Grinding
Authors: Tuff Mark A. 
Published: March 2019

AbstractThis study was done to learn which elements are being contributed as contaminants in the sample preparation equipment used at the New Mexico Institute of Mining and Technology (NMIMT). The apparatus investigated included a steel jaw crusher, a ceramic jaw crusher, two aluminum plates as a crusher and grinder, a steel spinning plate pulverizer, an alumina ceramic spinning plate pulverizer, an automated agate mortar and pestle, a high speed spectromill grinder with a tungsten carbide mortar and pestle, and the halves of a sliced quartzite cobble. Major-element Oxides and trace elements were analyzed by x-ray fluorescence. Some of the trace elements were analyzed by instrumental neutron activation analysis. The expected contamination of ferroalloy elements from steel were present in varying quantities, as were tungsten, tantalum and cobalt fron the tungsten carbide. There was unexpected contamination of sulfur and lead from the steel pulverizer.
A Fusion Method for the X-Ray Fluorescence Analysis of Portland Cements, Clinker and Raw Materials Utilizing Cerium (IV) Oxide in Lithium Borate Fluxes
Authors: Barger Gregory S. 
Published: March 2019

AbstractThis method describes the addition of cerium (IV) oxide to a lithium borate flux. CeO2 provides a non-analytic glass former to the melt production. CeO2 also acts as an interelemental buffer replacing the use of lanthanum oxide for long wavelength absorption. With cerium oxide addition, excellent results are produced, resulting in part from the elimination of recrystallization problems encountered with lanthanum oxide use. Analytical results easily meet the ASTM C-114 qualification requirements for rapid method analysis of hydraulic cements.
Application of Computers in Electron Probe and X-Ray Fluorescence Analysis
Authors: Rasberry Stanley D. 
Published: March 2019

This paper is a review of automation of electron microprobe and x-ray fluorescence instrumentation. Such a review seems timely because of the great increase in the application of computer systems in this field over the past decade. Some of these applications have been conceived to meet true technological needs while in other cases they have “been undertaken to “keep up with the Joneses.” I would like to show not only what automated systems are now feasible but also when and how they should he employed. The “when” and “how” of automation are largely dependent upon the application being considered; in this study, x-ray applications have been divided into the following classes;
(1)on-stream process-control,(2)off-line quality assurance,(3)routine service laboratory,(4)general purpose analytical laboratory.
Several phases are present in these classes, including: specimen preparation and loading, measurement, data acquisition and transfer, data processing and display, and finally, archival data storage. Various workers have undertaken the automation of all these operations in one or the other of the classes of applications; from a review of their work and by examining details of each operation within the framework of a given application, we can now draw conclusions on the extent of desirable automation.
Determination of Zirconium, Hafnium, Niobium, Tantalum, Molybdenum and Tungsten in Aqueous Solutions by Radioisotopic Excited X-Ray Fluorescence
Authors: Chan Frank L. , Jones W. Barclay 
Published: March 2019

Previous investigations on the quantitative determination of sulfur, chlorine, potassium, calcium, scandium and titanium in aqueous solutions by a radioisotopic excited fluorescent spectrometer has been extended to include other elements which are very difficult to separate and determine quantitatively by chemical methods. Six elements taken for the investigation and some of the results to be presented in this paper are:
(1)zirconium,(2)hafnium,(3)niobium,(4)tantalum,(5)molybdenum and(6)tungsten.
As in previous investigations, aqueous solutions have been used because of the ease in obtaining exact concentrations and homogeneous mixtures of the elements under investigation.In the earlier investigations which have been reported in this conference, lighter elements (atomic numbers ranging from 16 to 22) were used for the investigation. In the present studies, however, comparatively heavier elements have been used. Therefore a radioisotope such as iron 55 used earlier is not suitable because it cannot excite the K x-ray of these elements. To excite the K and L of these elements, we use the radioisotope iodine 125. The advantage of using this radioisotope is that it is inexpensive and commercially available although its half-life is comparatively short.The spectrometer used with further improvements has been described and presented earlier. We used a multi-channel analyzer of 1000 in the present investigation, A liquid cell was specially designed for thisr study. Chemicals used for preparation of solutions were of reagent grades. Some of them had to be specially prepared. For example, hafnium, often contaminated with zirconium, was specially prepared and checked spectroscopically. Some difficulties have been encountered in preparing concentrated solutions such as niobium and tantalum due to the inherit characteristics of these elements to form insoluble compounds. Procedures will be described for the preparation of these solutions. Instruments used and results will be presented in this paper.
Simultaneous Spiral Recording of Pole Figures on Polaroid Film for Texture Goniometers
Authors: Ebel H. , Ebel M. F. 
Published: March 2019

The X-ray reflection method according to Schulz is used for investigations of textures in rolled materials. The pole figures are measured either along spirals or along circles. Points of equal intensity are transposed from the record of X-ray intensity to a spiral diagram. Finally contour lines are delineated, pointing out regions of equal pole density. Three ways are known for simplification of the evaluation.
a)The results of the measurement are stored, evaluated by a computer and the pole figure is plotted. Points of equal pole density are represented by equal symbols (2 ,3 ).b)The pole figure is recorded synchronously with the X-ray measurement along circles or spirals. Ranges of different pole density are characterized by different colors (4 ,5 ).c)The pole figure is recorded on a photographic film along a spiral. The blackening depends on the measured countrate (6 ,7 ).An outline on different instruments using photographic registration is given.
Light Element Analysis
Authors: Baird A. K. 
Published: March 2019

Qualitative and quantitative analyses of elements below atomic number 20, and extending to atomic number 4, have been made practical and reasonably routine only in the past five to ten years by advances in: 1) excitation sources; 2) dispersive spectrometers; 3) detection devices; and 4) reductions of optic path absorption. At present agreement is lacking on the best combination of parameters for light element analysis. The principal contrasts in opinion concern excitation.Direct electron excitation, particularly as employed in microprobe analysis (but not limited to such instruments), provides relatively high emission intensities of all soft X-rays, but also generates a high continuum, requires the sample to be at essentially electron gun vacuum, and introduces practical calibration problems (“matrix effects“). X-ray excitation of soft X-rays overcomes some of the latter three disadvantages, and has its own limitations. Sealed X-ray sources of conventional or semi-conventional design can provide useful (if not optimum) light element emission intensities down to atomic number 9, hut with serious loss of efficiency in many applications below atomic number 15 largely because of window-thinness limitations under electron bombardment.
Forty Years of Quantitative Diffraction Analysis
Authors: Alexander Leroy E. 
Published: March 2019

In this paper an attempt is made to review in rather broad perspective the origins and history of quantitative methods in diffraction analysis, at the same time leaving an in-depth examination of the present state of the art to other better qualified contributors to this conference. Space limitations preclude mention of many significant contributions, for which I am very sorry. It will be possible to review only a number of pivotal historical events, while also taking note of certain other researches that seem representative of historical and present-day trends.The birth of quantitatively meaningful analysis in the mid-1930s depended upon a realisation of, and allowance for, the alteration of the diffracted intensities resulting from absorption of x-rays by the specimen. Furthermore, advances in the art achieved during the past forty years have been closely related to improvements in the treatment of the absorption factor.
Accuracy and Precision of Intensities in X-Ray Polycrystalline Diffraction
Authors: Parrish W. , Huang T. C. 
Published: March 2019

AbstractThe integrated and peak intensities of a series of silicon powder samples of various crystallite sizes were measured with a computer automated diffractometer and a profile fitting method (PFM). The accuracy of the PFM was better than 0.003% in computing the integrated intensities. The PFM gave more precise values than would be expected from counting statistics of the peak intensity. The average difference between each measurement and the average intensity was 0.5% with little dependence oo the absolute intensity. Crystallite sizes have a large effect and it is essential to rotate the specimen around the diffraction vector. The best results were obtained with <10 μm particles. Larger sizes decrease the absolute intensities and change the relative intensities. Structure refinement using the POWLS (powder least squares refinement) program showed the presence of (111) preferred orientation even in the <10 μm specimens. R(Bragg) decreased from 4.3% to 0.7% by including the preferred orientation correction in the refinement.
An Evaluation of Some Profile Models and the Optimization Procedures Used in Profile Fitting
Authors: Howard Scott A. , Snyder Robert L. 
Published: March 2019

AbstractThis paper examines some of the concerns regarding the development of an algorithm for the refinement of X-ray diffraction profiles. The object of the algorithm is to provide a time efficient method of refinement through the choice of a suitable profile function and optimization technique.Seven profile models were tested using a least-squares error criterion for refinement. Profile parameters were refined using non-linear Gauss-Newton, Marquardt and Simplex algorithms. The profiles were refined on a pattern digitally collected from an NBS 640A silicon sample.The results of this study indicate the repetitive function evaluations are not necessarily the time consuming step in the profile fitting process. As the number of parameters needed to evaluate the profile and the number of points in the profile increases, the time required to perform the mathematics in the Gauss-Newton and Marquardt algorithms increases. Although the Simplex was most memory and time efficient, our Gauss-Newton optimization algorithm provided a more consistent set of refined values which were not as dependent on the initial estimates of the parameters.The most favorable results were obtained by using the split Pearson VII profile with the alpha 2 reflection fixed in position and intensity with respect to the alpha 1 reflsction. This method generated the lowest residual error and was found to avoid some problems resulting from the alpha 1, alpha 2 line overlap.
Computer Search/Match of Standards Containing a Small Number of Reflections
Authors: Huang T. C. , Parrish W. , Post B. 
Published: March 2019

AbstractA simplified and effective computer Search/Match method is described in which no more than 12 largest d-value reflections regardless of intensities are used for the Powder Diffraction File standards. A quantitative procedure utilizing the figure-of-merit in the IBM Search/Match method was employed to show the applicability to inorganic, mineral and organic mixtures. The analyses gave the same results as the complete File but the standard databases and analysis time are reduced by about a factor of two. Search/Match without using intensities also gave the same results; this may be useful when instrument geometry and/or preferred orientation cause large errors in the relative intensities. The error limits in measuring the d-spacings were found to vary from ±0.1° to 0.5° (26) depending on the degree of overlaps.
XRF Analysis by Combining the Standard Addition Method with Matrix-Correction Models
Authors: De Groot Peter B. 
Published: March 2019

AbstractThe standard addition method is often useful for singleelement analyses in matrices of unknown composition or those difficult to reproduce. Results are good at low concentrations where concentration vs. intensity is approximately linear, but serious errors occur at higher concentrations. A method is shown here for greatly extending the range of the standard addition approach by combining it with with matrix correction models. Expressions incorporating the well-known alpha-or beta-correction coefficients are derived for the observed intensities before and after addition of the analyte. K-ratio measurements on the saraple plus a single standard addition allow the calculation of the correction coefficient and analyte concentration. Several standard addition levels can also be used and concentration obtained from non-linear regression analysis. A computer program has been developed to perform these calculations. Analyses of CuO on silica and of four metals in a metal oxide catalyst over a wide range of concentrations gave results with a relative accuracy generally within ±5%.
Determination of Light Elements on the Chem-X Multichannel Spectrometer
Authors: Gurvich Y.M. , Buman A. , Lokshin I. 
Published: March 2019

For X-ray fluorescence determination of light elements, vacuum X-rays spectrometers are usually used to increase the transmission of the optical path for the soft X-radiation. A vacuum of about 50μHg is required for the determination of elements with atomic numbers down to 9(F).A vacuum system however, complicates the sample presentation mechanism of a spectrometer; it requires vacuum seals, additional fastening of the flow detector window and, as a results, increases the price of the spectrometer.
Unification of “Standard Background” Technique using Scattered Radiation in X-Ray Fluorescence Analysis (XRF)
Authors: Smolniakov V. I. 
Published: March 2019

AbstractSome x-ray fluorescence - concentration relationships in the framework of XRF were researched. Fundamental calculation approaches for primary fluorescence and incoherent scattering were realized for evaluation of matrix influence. A new binary approach was produced for the cases considered, and its unification was related to the empirical and regression types of the “standard background” technique, widely used in the analytical practice of XRF. It is confirmed that application of the calculations by fundamental parameters (FP) in combination with the empirical approach allows the reduction of the set of standards (to as few as one) in the analysis procedure with wide variations in matrices and concentrations, without loss of accuracy.
X-Ray Fluorescence Analysis of Nonhomogeneous Materials by Δμ-Correction Method
Authors: Karmanov V. I. , Zagorodny V. V. 
Published: March 2019

AbstractThe fundamental parameters method (FPM) enables one to determine with high accuracy the chemical composition of homogeneous samples, having only one reference sample. However, the reference sample composition should be similar to that of the samples analyzed.The x-ray fluorescence analysis of multicomponent heterogeneous materials (ores, minerals, their mixtures, welding electrode coating mixtures, fluxes, etc.) is made by the Δμ-correction method based on the combined use of the fundamental and empirical correlations maintaining all the advantages of the FPM. Sample composition is calculated on the basis of the element intensities measured in the sample and in the reference specimen and is corrected for the disturbing effect of excitation conditions and heterogeneity as well as the calculated values of one of the fundamental parameters (μ1). At the preliminary stage of calibration, the coefficients are determined using regression and the absolute fundamental expression for the element fluorescence intensity.
Trace Element Analysis using Total-Reflection X-Ray Fluorescence Spectrometry
Authors: Prange Andreas , Schwenke Heinrich 
Published: March 2019

AbstractFor the application of TXRF in trace element analysis, two characteristic features of the total reflection of X-rays are exploited. These are the high reflectivity on flat surfaces and the low penetration depth of the primary radiation. This allows the application of TXRF for both chemical trace and ultra-trace element analysis on the one hand and surface analysis on the other. For chemical trace clement analysis, total reflection on a highly polished substrate is characterized by a high reflectivity, which leads to a drastic reduction of the spectral background. The sample to be analyzed is prepared on the substrate as a residue of small quantities by evaporation from solutions or fine-grained suspensions. Instrumental detection limits of a few pg or sub-ng/ ml−1 arc state of the art for commercially available equipment. Besides the high detection power, internal standardization is another important feature of TXRF, enabling very simple quantification of the detected elements. The small sample mass required enables especially ultra-micro analytical questions to be tackled. For trace element analysis in surfaces the low penetration depth of the primary radiation under the conditions of total reflection is exploited. The penetration depth is in the range of a few nanometers, hence, TXRF is intrinsically surface sensitive. Detection limits better than 1010 atoms/cm2 are obtained for metal impurities on silicon wafers. For the examination of layered structures elemental composition, layer thickness, and density can be derived from die angle-dependent fluorescence intensities. The present paper describes the basic features of the total reflection of X-rays and gives some representative examples of the different uses of TXRF in trace element analysis.
Characterization of Near Surface Layers by Means of Total Reflection X-Ray Fluorescence Spectrometry
Authors: Schwenke H. , Gutschke R. , Knoth J. 
Published: March 2019

AbstractTotal Reflection X-ray Fluorescence Spectrometry (TXRF) has been used for the characterisation of a 20 nm thick Ni/Fe/Cr-layer on a silicon substrate. Instrumental aspects of the technique as well as the data evaluation procedure on the basis of modelling calculations are outlined in this paper. The effect of standing waves is discussed by means of the selected example. This particular layer serves also as an illustration of the capabilities and limitations of TXRF. At least three surface parameters are covered by the technique, elemental composition, density and layer thickness.
Application of Total Reflection X-Ray Fluorescence Spectrometry to Drug Analysis
Authors: Nomura S. , Minomiya T. , Tanlguchi K. , Ikeda S. 
Published: March 2019

AbstractA new procedure for indirect determination of pharmaceutical drugs is presented. The procedure consists of extracting ion pairs between organic basic compounds, that is, pharmaceutical drugs and cobalt tetrathiocyanate and of determining Co contents in the organic extraction phase using total reflection X-ray fluorescence spectrometry. Quinine, papaverine and pilocarpine are used as pharmaceutical drugs and 1,2-dichloroethane is adopted as extraction medium. Quinine cobalt tetrathiocyanate complex was isolated and was analyzed by FT-IR (Fourier Transform Infra-Red spectroscopy) suggested that approximately 4 ng of quinine could be detected by 1 μl of sampling of organic phase under ideal conditions using total reflection X-ray fluorescence spectrometry. These drugs have their own optimal pH for extraction. This technique can be applied to cocaine analysis.
An Integrated X-Ray Tube - Polarizer EDXRF-Spectrometer in Cartesian Geometry
Authors: Rieder Robert , Wobrauschek Peter , Aiginger Hannes 
Published: March 2019

AbstractLinear polarized x-rays are used as exciting radiation to reduce the background and to improve the detection limits in XRF. A combination of an x-ray tube and a measuring module realizing a compact cartesian geometry was constructed. An on-line adjustable Bragg-polarizer, a Barkla-polarizer or a secondary target can be used optionally. The anode material of the tube can be changed easily.