bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Dispersive Diffraction in a Diamond Anvil High Pressure Cell Using Synchrotron and Conventional X-Radiation
Authors: Black David R. , Menoni Carmen S. , Spain Ian L.
Published: March 2019

A wide range of structural studies have been carried out in high pressure diamond anvil cells using x-rays. The most common experimental geometry is shown in Fig. 1a. The incident x-ray beam passes axially through the first diamond and enters the sample, typically 100-300 μm in diameter and 20-100 μm thick; the diffracted x-rays exit via the second diamond. Energy-dispersive detection techniques (EDXRD) have been used. However the intensity of diffracted radiation from the sample is weak, so that typical exposure times with a conventional, fixed anode, x-ray source are typically one to several days.Accordingly, higher intensity radiation from synchrotron sources has been used for these experiments.
Application of a Polarized X-Ray Spectrometer for Analysis of Ash from a Refuse-Fired Steam Generating Facility
Authors: Maddox William E.
Published: March 2019

The Refuse-Fired Steam Generating Facility (RFSGF) funded jointly by NASA, the U.S. Air Force, and the City of Hampton is presently in operation at the NASA/Langley Research Center in Hampton, Virginia. The facility b u m s approximately 200 tons/day of refuse and supplies approximately 170x103 tons/year of steam at 350 psig to the Langley Center. Concentrations of trace elements in the bottom ash and in the ash from the electrostatic precipitators were determined using the Murray State Polarized X-Ray Fluorescence Spectrometer (PXFS), The PXFS uses x-rays from a Phillips PW1140/96 x-ray generator in a double scattering process to make quantitative measurements on elements in pressed briquette samples. The double scattering process is used to produce polarized x-rays for excitation of the samples, Minimum detectable limits (MDL) of 1-3 ppm are achieved for elements with Z = 26 to 42. Lower Z elements have significantly higher MDL's; the lowest Z element detected, sulfur, has an MDL of 100 ppm. Elements with Z's higher than 42 have MDL's in the range of 4-10 ppm. Elements detected in the RFSGF ash were S, Cl, K, Ca, Ti, V, Mn, Fe, Cu, Zn, Br, Rb, Sr, Zr, Sn, Sb, and Pb. The concentrations ranged from a few ppm to several mg/g.
Spectra of X-Ray Tubes with Transmission Anodes for Fundamental Parameter Analysis
Authors: Ebel Horst , Ebel Maria F. , Pöhn Christian , Schoßmann Bernd
Published: March 2019

The approach for the description of the emission of white and characteristic x-rays from standard x-ray tubes is modified for an application to transmission anodes. This modification is based on the assumption of a negligible penetration depth of the electrons in comparison to the thickness of the anode. The results of our considerations are presented for Cu, Mo and W anodes with two different thicknesses. For comparison, the spectra of standard anodes which have been operated with identically high voltages and anode currents are given. A typical feature of transmission anodes is their spectral hardening of the energy distribution of emitted photons. A further interesting detail is the development of narrow band excitation anodes as can be seen from the results for Mo. With anode thicknesses of approximately 200 μm and a high voltage of 30 kv the spectral distribution is restricted to an energy ranging from 15 to 20 keV.
Angle Dependent XRF for the Analysis of Thin Al(x)Ga(1-x)As Layers on GaAs and Thin Zn Layers on Steel
Authors: Ebel Horst , Ebel Maria F. , Svagera Robert , Heller Martin , Kaitna Roland
Published: March 2019

Depth profiling is performed by monochromatic primary excitation using variable incidence and take-off angles, A proper choice of the photon energy and the angular range of incident radiation allows depth profiling of layered structures without comparison to reference samples. The method has been verified for two different systems. Thin Al(x)Ga(1-x)As-layers on GaAs substrates are characterized by thickness D and atomic ratio x. For an excitation of AlKα-radiation by SiKα-radiation from a secondary target, the lower limit of measurement is layer thicknesses of 40 to 80 nm at x=0.6 to 0.4. Zn-coatings on steel have been investigated with CuKα radiation for selective excitation of FeKα-radiation from the substrate and with GeKα radiation for the excitation of ZnKα radiation from the layer. The scatter of the results required a measurement of the lateral homogeneity of the coating thickness. These experiments have been performed by step scanning in steps of 1 mm under fixed incidence and take-off geometry over an area of 30mm*30mm and excitation with unfiltered radiation from a Cu target diffraction tube with a beam cross section of less than 1 mm2. The obtained thickness distribution of ±20% has been confirmed by electron micrographs.
Combined Small-Angle Neutron and X-Ray Scattering Studies of Polymers
Authors: Wignall George D.
Published: March 2019

Scattering technigues have been employed since the beginnings of polymer science to provide information on the spatial arrangements of macromolecules. The first measurements were made in the 1920s and were concerned primarily with the determination of crystal structures via the Bragg law

nλ = 2dsinθ.
X-Ray Examination of Type 310S Stainless Steel during its Oxidation in Air at 900°C*
Authors: Cavin O. Burl , Wolf J. S.
Published: March 2019

Type 310S stainless steel was exposed in air at 900°C and simultaneously examined periodically by X-ray diffraction in an attempt to determine the structural evolution of the compounds formed on its surface. The adherent oxide product was found to be a two-layered scale composed of an inner sesquioxide and an outer spinel layer. Both of these compounds exhibited systematic changes in their unit cell sizes as a function of increasing exposure time at constant temperature. The spinel showed an increase in its lattice parameter while the sesquioxide and stainless steel substrate both had decreases in their parameters proportional to the square root of exposure time. In each of the three phases, the rate of change was constant up to approximately four hours after which the parameters approached a limiting value. Evidence also exists for the presence of at least localized stresses in the scales.
PC-Based Management and Analysis of X-Ray Residual Stress Data
Authors: Courtney S. B. , Tricard M. J. , Hendricks R. W.
Published: March 2019

The authors have developed two independent software packages that store x-ray peak locations, integrated intensities and full-width half-maximum intensity data as a function of diffractometer tilt and orientation angle; this information is used to compute residual stress tensor values. Each program retrieves the fitted x-ray peak locations from a dBASE-compatible data set that is independent of both x-ray diffractometer and acquisition software. Machine-specific routines have been coded to transfer peak data and general diffraction setup information from several different x-ray acquisition platforms into this common format. The two database management programs provide stand-alone storage, retrieval, analysis and graphic output of data, and thus have become practical laboratory vehicles toward establishing a standard database format for storing x-ray strain measurements and the residual stress values calculated therefrom.
High Resolution Measurement of Surface Misorientation in Single Crystal Wafers
Authors: Fatemi M.
Published: March 2019

A simple method for high-resolution measurement of surface misorientation in electronic materials is introduced. The technique combines laser optical alignment with double-crystal x-ray diffraction to yield a typical sensitivity of better than 1-2 arc sec. The technique can also be used to make corrections in spectrometric measurements in which commonly ignored rocking - curve errors may be significant.
Non-Destructive Chemical-State Analysis of Thin Films and Surface Layers (1-1000 nm) by Low-Energy Electron-Induced X-ray Spectroscopy (LEEIXS)
Authors: Gyani Angeli K. , McClusky Phillip , Urch David S. , Charbonnicr M. , Gaillard F. , Romand M.
Published: March 2019

The penetration depth of 1-12 keV electrons in most materials is less than one micron and the characteristic soft x-rays that are produced can be used to identify the elements present in the surface. Varying the energy of the incident electron beam enables the depth of analysis to be controlled.

Soft x-rays often exhibit large 'chemical effects' (changes in peak profile and peak position) which can he correlated with chemical changes. A study of such effects for each element present in the sample surface, as a function of electron-beam energy, can in some cases, permit changes in the chemical state (valency - coordination number-spin state etc.) to be determined as a function of depth.

Such analyses can be carried out either in a conventional x-ray spectrometer in which the x-ray tube has been replaced by a gas-discharge source, or in a spectrometer in which the sample is bombarded with electrons from a normal electron gun. In this paper these techniques are outlined and some applications reviewed:- the analysis of oxide layers on aluminium and steel, the analysis of aluminium-nitride layers produced by MOCVD on gallium arsenide, the analysis of silica fiims (with added boron and phosphorus oxides) on silicon and the analysis of zinc-oxide films on glass.
Strain and Particle Size of Palladium Metal Powders by Time-of-Flight Neutron Diffraction
Authors: Lawson A. C. , Conant J. W. , Talcott C. L. , David M. A. , Vaninetti J. , Goldstone J. A. , Williams A. , Roof R. B. , Von Dreele R. B. , Hitterman R. L. , Richardson J. W. , Faber J.
Published: March 2019

We have determined the strain and particle size for several samples of palladium powder by time-of-flight nrutron powder diffraction on two different diffractometers and by x-ray powder diffraction. The results are compared and found to be in fair agreement. The time-of-flight method gives good enough precision to reveal deficiencies in the simple models used for strain and particle size line broadening.
TXRF Spectrometer for Trace Element Detection
Authors: Hegedüs F. , Winkler P. , Wobrauschek P. , Streli Christina
Published: March 2019

A method to measure low level iodine concentrations by means of a Total Reflectance X-Ray Spectrometer (TXRF) was presented at the 1986 and 1988 Denver X-Ray Conferences (Ref. 1 and 2.). The optimum set-up of the spectrometer for this purpose was obtained by using a Cu-anode tube. The collimated beam was two times totally reflected: first on the mirror and then on the synsil sample substrate. By these means the undesired high energy bremsstrahlung was almost eliminated. This operational mode is very convenient for iodine measurement by L-lines. The detection limit of iodine was as low as 100 pg.

For simultaneous measurement of several elements (I2<Z<83) it was necessary to change the set-up of the spectrometer.
A Compact On-Line XRF Analyzer for Chemical and Petrochemical Processes
Authors: Kalnicky D. J. , Ahonen A. I. , Hietala M. J. , Kauhanen K. J.
Published: March 2019

The need for process control has led to the development of improved instrumentation for measuring chemical contents of process streams. In many instances, on-line X-ray Fluorescence (XRF) analysis represents a straightforward method to accomplish these kinds of analyses. The sample preparation is often easy compared to many other methods and the XRF analyzer can be calibrated with process stream or artificial standards. Results are obtained in a time frame suitable for closed-loop control strategies. The Courier 10 is a new, compact on-line XRF analyzer which has been developed for chemical and petrochemical process applications such as sulfur and/or lead in gasoline; calcium in polymers; and chrome, iron ,nickel in metal treatment baths.
Alumina Characterization by XRF
Authors: Feret Frank R.
Published: March 2019

One of the most important properties that characterizes alumina is its elemental composition. Although XRF has been applied to the analysis of aluminas for the past three decades, special aluminas have always presented a maj or challenge. Moreover, only recently did it become possible to analyze for light elements such as Na. Two new sample preparation techniques for elemental analysis of aluminas by XRF were developed. One is based on briquetted powders, another involves fused samples. Their advantages and limitations will be presented. In the case of fusion one analytical program was applied to aII types of aluminas, The performance of each method will be discussed.
Application of Fundamental Parameter Software to On-Line XRF Analysis
Authors: Leland D.J. , Leyden D.E. , Harding A.R.
Published: March 2019

X-ray fluorescence analysis (XRF) is an analytical method which has been adapted with considerable success to on-line industrial process analysis with various degrees of sophistication. Process analysis XRF systems range from relatively simple units utilizing radioisotope sources with non-dispersive analyzers to complex wavelength dispersive systems in a central location receiving samples from a number of process streams. The advantages of on-line process analytical instrumentation for quality control, regulatory 2 compliance and safety considerations are well documented. ' Advances in the development of low maintenance thermoelectrically cooled Si(Li) detectors have made energy dispersive X-ray fluorescence analysis (EDXRF) even more amendable to on-line process analysis. EDXRF is an important method of on-line instrumentation because of its ability to simultaneously detect many elements.
On-Site Tests of a XRD/XRF On-Line Process Analyzers
Authors: Ahonen A. , Alfthan C.V. , Hirvonen M. , Ollikainen J. , Rintamaki M. , Saloheimo K. , Virtanen P.
Published: March 2019

X-ray fluorescence (XRF) has been successfully used for more than 20 years as an on-line analysis method for controlling various industrial processes where the concentrations of different elements must be known in the process streams. In many industrial processes, however, the knowledge of the concentrations of different minerals, rather than those of the elements, is of prime importance. Examples of such processes are numerous; plants concentrating apatite for fertilizer and detergent manufacturers, paper filler producers manufacturing kaoline, titanium dioxide (rutile) and talc, potash concentrators and different crystallization processes.
Concepts of Influence Coefficients in XRF Analysis and Calibration
Authors: Rousseau Richard M.
Published: March 2019

A new computer program, named CiROU, has been written to determine the chemical composition of homogeneous samples analyzed by X-ray fluorescence spectrometry (XRF). It uses the furdamental algorithm to convert measured intensities into concentrations anc to correct for matrix effects and runs on any IBM-PC/XT/AT, PS/2 or compatible corrputer.

The program is very easy to use mainly because it is a step-by-step guide to the routine process of analyzing specimens by XRF and because a user friendly interface makes up a main menu bar containing six major options, which provide several other options inside a pull-down window system.

The program is applicable to specimens of any composition with the utmost accuracy that can be obtained from the fundamental-parameters method. It’s unique calibration procedure still adds to the accuracy by eliminating the bias between theory and reality.

The program is a complete “off-line” program allowing to perform all the steps of an XRF analysis: calculation of theoretical influence coefficients, calibration, reading of measured intensities, calculation of net intensities and concentrations of unknowns, print-out of analytical reports and data transmission to or from an external computer.
Applications of a Laboratory X-ray Micropsobe to Materials Analysis
Authors: Carpenter D. A. , Taylor M. A. , Holcombe C. E.
Published: March 2019

A laboratory-based X-ray microprobe, composed of a high-brilliance microfocus X-ray tube, coupled with a small glass capillary, has been developed for materials applications. Because of total external reflectance of X rays from the smooth inside bore of the glass capillary, the microprobe has a high sensitivity as well as a high spatial resolution. The use of X rays to excite elemental fluorescence offers the advantages of good peak-to-background, the ability to operate in air, and minimal specimen preparation. In addition, the development of laboratory-based instrumentation has been of Interest recently because of greater accessibility when compared with synchrotron X-ray microprobes.
Quantitative Analysis of Arsenic Element in a Trace of Water Using Total Reflection X-ray Fluorescence Spectrometry
Authors: Ninomiya T. , Nomura S. , Taniguchi K. , Ikeda S.
Published: March 2019

Various kinds of compounds containing arsenic have been used in the world as rat poisons, agricultural chemicals and so on. In the field of semiconductor materials, AsH3 is used as a doping gas on silieon-wafer substrates and GaAs is now also investigated as a wafer substrate instead of Si wafer.

As for quantitative analysis of arsenic, atomic absorption spectrometry (AAS) and inductively coupled plasma atomic-emission spectrometry (ICP-AES) have often been used. In these methods, usually, oomplioated pretreatments such as preconcentration and separation have been needed in order to obtain reproducible values for arsenic.
Characterization of Permalloy Thin Films via Variable Sample Exit Angle Ultrasoft X-ray Fluorescence Spectrometry
Authors: Andermann George , Fujiwara Francis , Huang T.C. , Howard J.K. , Staud N.
Published: March 2019

Recently variable sample exit-angle x-ray fluorescence spectrometry (VEA-XRF) has been shorn to be a useful analytical tool for monitoring the oxidation of the surfaces of bulk Cu, Ni as well as that of Fe. In these studies advantage was taken of the well known phenomenon that for each transition metal oxide (MO) Lβ/Lα intensity ratio value is higher than for the transition metal (M), itself. Within the limits of the photon-escape depth de, which for these photons are generally below 5000 Å, varying the sample exit-angle θ offers an opportunity for seeing whether or not the oxidation of the surfaces of bulk M belongs to one of the following two classes: (I) uniform oxidation throughout the entire observable sample-depth, (II) preferential oxidation of the top surface layer, i.e. depth dependent oxidation.
Thickness Measurement of Epitaxical Thin Films by X-ray Diffraction Method
Authors: Chaudhuri J. , Shah S. , Harbison J.P.
Published: March 2019

A method was described for determining the thickness of epitaxical thin films common to electronic materials. The equations were developed based on the kinematical theory of X-ray diffraction and effects of both primary and secondary extinctions were considered. As an example of the applications of this method, thickness measurement of AlGaAs thin films on GaAs was demonstrated. These films were grown by molecular beam epitaxy. The integrated reflected intensities from the film and the substrate were obtained by the X-ray double crystal diffractometer. An excellent agreement was obtained between the results from X-ray measurements and RHEED oscillation data.
Standard Deviations in X-Ray Stress and Elastic Constants Due to Counting Statistics
Authors: Kurita Masanori
Published: March 2019

X-ray diffraction can be used to nondestructively measure residual stress of polycrystalline materials. In x-ray stress measurement, it is important to determine a stress constant experimentally in order to measure the stress accurately. However, every value measured by x-ray diffraction has statistical errors arising from counting statistics. The equations for calculating the standard deviations of the stress constant and elastic constants measured by x-rays are derived analytically in order to ascertain the reproducibility of the measured values. These standard deviations represent the size of the variability caused by counting statistics, and can be calculated from a single set of measurements by using these equations. These equations can apply Lu any meuhud for x-ray stress ifiesuremenL. The variances of the x-ray stress and elastic constants are expressed in terms of the linear combinations of the variances of the peak position. The confidence limits of these constants of a quenched and tempered steel specimen were determined by the Gaussian curve method. The 95% confidence limits of the stress constant were -314 ± 25 MFa/deg.
Advantages of the Vector Method to Study the Texture of Well Textured Thin Layers
Authors: Vadon Albert , Heizmann Jean-Julien
Published: March 2019

Depositing a thin layer of noble matter on a less noble material is a standard means of improving the qualities of the material. The characterization of the deposit is essential to understand tile physical phenomena involved and to improve the final product. Two physical parameters of the layer deposited are of great consequence on the behavior of the material as a whole:

-

the crystallographic and morphological textures related or not related to those of the substratum

-

the internal stresses.
Chemical Constraints in Quantitative X-ray Powder Diffraction for Mineral Analysis of the Sand/Silt Fractions of Sedimentary Rocks
Authors: Smith D. K. , Johnson G. G. , Kelton M. J. , Andersen C. A.
Published: March 2019

Quantitative X-ray powder diffraction using the complete digitized diffraction pattern has proved to be an effective approach to improving the accuracy of the analysis of complex mineral mixtures, provided representative reference patterns and accurate Reference Intensity Ratio (RIR) factors arc available for each component phase. However, chemical and structural variability of common rock-forming minerals may complicate the pattern fitting approach. A method has been developed which utilizes X-ray fluorescence chemistry of an unknown and realistic compositional ranges for component phases as constraints on the quantitative XRD analysis without significant compromise of the pattern fit. This unique approach no only yields accurate weight fractions, but also provides indications of the specific compositions of each phase present in the mixture.
Use of the Crystal Data File on CD-ROM
Authors: Holomany Mark , Jenkins Ron
Published: March 2019

We have recently described the use of the Compact Disk Read Only Memory disk for the storage of data in the Powder Diffraction File (PDF). This work has now been extended to include the NBS (1987) Crystal Data File (CDF). The CDF contains 115,753 entries of which 59,613 are Inorganic materials and 56,140 organic. The data base can be accessed either by means of bit maps built on chemistry and subfile restrictions, or by means of a Boolean search system allowing combinations of search parameters including: chemistry; space group; cell volume; density and unit cell data.
Mechanically-Induced Phase Transformations in Plutonium Alloys
Authors: Wallace P. L. , Wien W. L. , Goehner R. P.
Published: March 2019

In this article, we show that mechanically-induced phase transformations can be readily achieved in two Pu-alloy systems. We have observed mechanically-induced phase transformations in both Ti-stabilized β-Pu and Ga-stabilized δ-Pu, In both of these alloys, the parent phase has been largely transformed to α-Pu, and the cause of these transformations was mechanical strain introduced by the metallographic sample preparation. For the Ga alloys, x-ray diffraction (XRD) patterns were taken at about 1.5-μm steps down to the undisturbed material in order to develop depth profiles of the surface damage. The total depth of the disturbed material in these alloys is estimated to be about 7.6μm, but this depth was not measured for the Ti alloys. The proportions of α-Pu and δ-Pu in the Ga alloys have been estimated using (a) a new quantitative phase analysis program (SPECQUAN) that uses multiple peaks of each phase in order to minimize the effects of preferred orientation and (b) an older manual technique (i.e., hand calculations). The results from these techniques are compared. SPECQUAN was developed to use the Specplot data file structure directly, thus reducing our data processing. The program is written in Fortran 77 and employs an external intensity ratio quantification procedure to obtain its results. XRD calibration has been done independently by means of accurate density measurements on a reference Ga alloy.
Comparison of Experimental Techniques to Improve Peak to Background Ratios in X-ray Powder Diffractometry
Authors: Istone William K. , Russ John C. , Stewart William D.
Published: March 2019

High peak to background ratios are especially important in powder diffractometry when attempting to identify minor phases in a sample or improving the limit of detection in quantitative determinations. Instrumental techniques to improve peak to background generally involve the employment of monochromatic or partially monochromatic radiation through the use of filters, crystal monochrometers, or pulse height discriminators.

In this study, a digital pulse height discriminator, configured as a card in a personal computer (Apple IIe) with appropriate software, is used in conjunction with a scintillation detector to improve peak to background ratios. The software allows the pulse height distribution to be scanned and the optimum pulse height window to be set for a given set of sample and instrumental conditions. Results obtained by this technique are directly compared with results obtained using a pyrolytic graphite monochrometer and beta filters. Examples cited include qualitative phase identification in both fluorescent and non-fluorescent samples and semi-micro quantitative analysis (determination of airborne silica).
Required Corrections for Analysis of Industrial Samples with Medical CT Scanners
Authors: Engler P. , Hunt P. K. , Armstrong E. E. , Friedman W. D.
Published: March 2019

As a technique for non-destructive materials analysis, computed tomography (CT) has been especially useful for studying the dependence of the structure of ceramics on manufacturing processes. CT also has been used for characterizing the lithology of reservoir cores while they are still contained in preservation material or a core barrel.

The parameter measured by CT is the X-ray attenuation coefficient, which is a function of both material density and material composition.
X-Ray Fluorescence Analysis (XRP) in Europe
Authors: Ebel H.
Published: March 2019

The European contributions to X-ray fluorescence analysis (XRF) have shown remarkable fluctuations with regard to time and can be divided into three groups, each of them covering about thirty years.

At the beginning there was the discovery of X-rays by Röntgen in 1895. He received the first Nobel Prize in physics (1901). Barkla (Nobel Prize in physics 1917) gave a description of the interaction of X–rays with matter–scattering (1904) and polarization (1906), absorption (1909) and fluorescence (1911). In 1912 the crucial experiment of Friedrich, Knipping and von Laue brought the confirmation on the nature of X–rays as part of the spectrum of electromagnetic waves (Nobel Prize in physics 1914).
X-Ray Microfluorescence of Geologic Materials
Authors: Boehme Dale R.
Published: March 2019

Elemental analyses of geologic materials were obtained using X-ray microfluorescence combined with simultaneous elemental digital mapping. The analytical results corroborate the information obtained by electron and optical microscopy methods. Zoned garnet and ore deposit specimens were analyzed and compared to information obtained from other analytical methods. The penetrating nature of the X-ray beam using this method provides elemental information from beneath the sample surface. The combination of this depth information with the surface information supplied by electron microscopy provides a more complete analysis of the sample than is possible with each technique alone. Minimal or no sample preparation along with the ability to examine materials in air enhances the microfluorescence and digital mapping analysis technique.
Application of the Inverse Monte Carlo Method to Energy-Dispersive X-Ray Fluorescence
Authors: Yacout A.M. , Dunn W.L.
Published: March 2019

The feasibility of utilizing the Inverse Monte Carlo (IMC) method to determine elemental amounts in homogeneous samples from energy-dispersive X-ray fluorescence (EDXRF) measurements has been investigated. IMC is a novel application of standard Monte Carlo that, in principle, allows a rather large class of inverse problems to be solved noniteratively, in the sense that the simulation is not repeated. IMC is implemented by hypothesizing values for the unknown parameters, executing a direct Monte Carlo simulation using these values and scoring the results with factors that contain the unknown parameters. By equating the resulting Monte Carlo estimators to the known measured responses, a system of algebraic equations is formed that may be soluble by standard numerical techniques. Advantages of IMC include the facts that it can be applied to complex (e.g., multidimensional) problems and that it is relatively efficient since the simulation is performed only once. In the EDXRF case, simplified assumptions have been used to construct an approximate IMC solution. The model provides a means to determine the elemental amounts in an unknown sample by treating the unknown composition as a perturbation around the composition of a fixed "reference" sample that contains the same elements as the unknown sample. Primary and secondary X-rays are included in the model. The resulting system of algebraic equations is nonlinear and solutions are obtained via an approximation. Since the model is based on correlated sampling techniques, several unknown samples can be modeled simultaneously provided that they contain the same elements and their compositions are sufficiently close to that of the assumed reference sample. Direct Monte Carlo was used to generate the relative intensities for eighteen different samples in a ternary (Ni-Fe-Cr) system; these results were then used in the IMC model to recover the sample weight fractions. Excellent results were obtained, demonstrating the feasibility of the approach.
Quantitative Analysis of Odd-Shaped Samples by X-Ray Fluorescence Spectrometry Using Intensity Ratios
Authors: Platbrood G. , Van De Velde H.
Published: March 2019

In industrial laboratories, a great diversity of samples is usually presented for analysis (alloys, powders, solutions, …). Fast results are invariably required so that methods with minimal preparation times have to be developed. This paper discusses a method for quantitative analysis of metallic samples in the form of clippings or odd-shaped fragments where the specimen surface does not cover the total surface of the sample holder. In some laboratories it is common practice to use sample holders with a small orifice to analyse sample fragments, but this method strongly reduces the fluorescent intensities. We have the feeling that a method that uses the whole surface of the specimen should be much welcomed.
The Use of Layered Synthetic Microstructures for Quantitative Analysis of Elements: Boron to Magnesium
Authors: Nicolosi Joseph A. , Groven John P. , Merlo Daryn
Published: March 2019

Layered Synthetic Microstructures (LSMs) were first reported as commercially available diffracting structures for routine x-ray spectrochemical analysis in 1984 (Nicolosi et al.). Innitially, these devices (PX-1 and PX-2) were intended for use as alternatives for Thallium Acid Phthlate (TAP) and Lead Octadeconate (LOD) for improved stability and diffracted intensity. Improvements in the analytical performance of X-Ray Spectrometers for the elements carbon to magnesium has met, and in some cases exceeded, innitial expectations. Having captured the interest of many new possible applications, developments for LSMs with larger 2d-spacing and greater reflectivity have continued.

Previous instruments employing LSMs have had difficulty in measuring X-Ray energies below the carbon K-series characteristic. Below the carbon K-edge energy, several significant phenomenon combine to reduce sensitivity. Among these are: 1) Reduced reflectivity of conventional LSMs, 2) Increased absorption at the polypropylene window of the detector, and 3) Greater electronic noise.
Energy Dispersive Analysis for Quality Assurance of Aluminum Alloys
Authors: Gurvich Yury M.
Published: March 2019

Traditionally, aluminum has been the most important raw metal material for the aerospace industry. Since the major part of aluminum production is consumed for aircraft, military, space, and other programs, sponsored or regulated by the U. S. Government, quality of various Al alloys is under governmental control. The representatives of the governmental agency are placed at each aluminum plant in order to assure a high quality of production on-site. A fast and reliable analytical method is essential to control the production process and to keep chemical composition of the alloys inside specified ranges.
Energy-Dispersive X-Ray Techniques for Accurate Heavy Element Assay
Authors: Ottmar H. , Eberle H. , Matussek P. , Michel-Piper I.
Published: March 2019

Energy-dispersive X-ray techniques can be employed in two different ways for the accurate determination of element concentrations in specimens: (1) spectrometry of fluoresced characteristic X-rays as widely applied in the various modes of the traditional XRF analysis technique, and (2) spectrometry of the energy-differential transmittance of an X-ray continuum at the element-specific absorption-edge energies.
Application of EDXRF Analysis to Continuous Industrial Process Monitoring
Authors: Weakliem J. H. , Kalnicky D. J.
Published: March 2019

Many manufacturing processes in the chemical industry require frequent monitoring of the composition of the product. Ideally, an analysis of this type should be simple to carry out, rapid, reliable, and not require a seperate analytical laboratory. Energy Dispersive X-Ray Fluorescence (EDXRF), due to its relative simplicity of instrumentation, speed of analysis, and non-destructive nature, is well suited to on-line applications, when used in conjunction with a flow cell.

A question that is frequently raised in this type of analysis is: How do the precision and accuracy of these measurements compare with measurements made upon the same solution in sample cups (static). The purpose of this study was to compare the precision and accuracy of on-line with static analyses of the same types of solutions.
Automated Quantitative XRF Analysis of Soda-Lime Glass Utilizing Pattern Recognition
Authors: Klimasara A. J. , Barry T. L.
Published: March 2019

A set of programs in Fortran 77 has been written to automate quantitative analysis on the Rigaku SMAX/PDP-11/73 XRF System. The spectrometer can be instructed and Trained to recognize spectral patterns of soda-lime glass or other materials.

The method of pattern recognition employed is based on the relative position of spectra-vectors in N-Dimension Euclidean feature space. The distance between 2 vector-points: is used as a classifier.

The software correlates between 2 Euclidean feature spaces:

- Spectra Feature-Space

- Chemistry Feature-Space

Quantitative results are extracted automatically and printed in laboratory report form. Mathematical modeling with associated software and the results obtained are presented.
Powder Diffraction Profiles and the Pearson VII Distribution
Authors: Brown Allan , Linde Sven
Published: March 2019

The background to the use of the Pearson VII function as a model for powder diffraction profiles was summarised in connection with the fitting of data obtained essentially from Guinier patterns (1). The algorithm developed for modelling single-wavelength profiles was found to be less effective when applied to diffractometer data generated by the Kα doublet. Diffractometer, rather than Guinier film data are generally to be preferred, however, for profile measurements. A new approach was accordingly made to devising an algorithm for this particular application. Numerical features of the method highlighted by this task are described below. Attention is also drawn to problems encountered when profiles are measured using a diffracted-beam monochromator (DBM).
Thermal Expansion Behavior of Pure and Doped Cordierite by Time-of-Flight Neutron Diffraction
Authors: Haas J. , Predecki Paul , Faber J. , Hitterman R. L.
Published: March 2019

Abstarct

In order to reveal the mechanism of the negative c-axis expansion in cordierite (4 MgO 4 Al2O3 10 SiO2), the thermal expansion of cordierite containing small amounts of Cs, Li, B, Ge, Sc and Ni-cations was investigated by time-of-flight neutron diffraction at temperatures between 22 and 750°C. The samples were prepared by melting the constituent oxides followed by quenching and devitrification to obtain the hexagonal form (Indialite). Using the neutron powder diffraction data, the atom positions in the space group P6/mcc were refined by Rietveld least squares analyses.

The expansion behavior of the cordierite structure could be explained in terms of the various kinds of constraints and the interatomic bond strengths of the structure. It was found that cordierite doped with Cs-cations shows the largest volume expansion, followed by the Li-doped sample. So-doped cordierite has the lowest volume expansion. All cordierite samples show positive expansion along the a-axis and negative expansion along the c-axis, except the Cs-doped sample which has positive expansion in both directions.
Instrumental Capabilites in X-Ray Diffraction Analysis: Comparative Techniques
Authors: Kincaid P. J. , Newman R. A. , Fawcett T. G.
Published: March 2019

The following study is an evaluation of several different types of instrumentation available for use in powder x-ray diffraction work. The particular units used are those at the Dow Chemical Company x-ray diffraction lab. The variety of instrumentation allows analyses from routine phase identification to more specialized work such as low-angle x-ray diffraction of polymers and high-resolution analysis for cell parameter refinements.

The purpose of this work is to compare the relative capabilities of these different instruments under typical day-to-day operating conditions. While not a comprehensive study, the conclusions drawn should be applicable to powder x-ray diffraction in general.
X-Ray Diffraction Studies Under Non-Ambient Conditions: Application to Transition-Metal Dichalcogenide Solid Lubricants
Authors: Skelton E. F. , Webb A. W. , Schaefer M. W. , Schiferl D. , Katz A. I. , Hochheimer H. D. , Qadri S. B.
Published: March 2019

During the past quarter-century, the field of high pressure research has undergone a quiet revolution. This has resulted from the creation and development of the diamond-anvil cell (DAC). Because diamonds are the hardest known materials, the highest static pressures can be attained and indefinitely held in these devices, recent pressure records have surpassed 400 GPa.
In Situ Crystallization Measurements on Fe-Zr Glasses Using an Automated High-Temperature Diffractometer with a Position Sensitive Detector
Authors: Zorn G. , Hellstern E. , Göbel H. , Schultz L.
Published: March 2019

Metallic glasses are mostly produced by fast quenching from a melt. The glass forming composition range in binary materials is thereby restricted to the area around eutectics. The production of metal-metal binary glasses in a much wider composition range is possible by employing a technique called 'mechanical alloying'. Using this technique the metallic class is produced as a powder which can be manufactured into any shape to make use of the properties the material exhibits in the amorphous state. During compacting, and also in some applications of the finished product, the glass has to endure elevated temperatures which might cause devitrification. Since this crystallization of a metallic glass usually results in the loss of properties essential for a certain application it is necessary to investigate this crystallization behaviour and thus receive information about a material's prospective performance in a particular application.
Microdiffraction With Synchrotron Beams (Or Ultra-High Pressure Research)
Authors: Skelton E. F.
Published: March 2019

Pressure is an important thermodynamical variable. It provides the most efficient means of altering interatomic distances while leaving the thermal energy of a system invariant. It therefore provides an important mechanism for testing theoretical models that are based upon atomic separations and crystallographic configurations. Like its counterpart, temperature, pressure can be used to assist chemical reactions or to bring about crystallographic phase transformations. New allotropes, formed under conditions of extreme pressure and/or temperature, may have physical properties that are significantly different from those of the material formed under normal conditions. A classic example is that of carbon: the hardness, electrical and thermal conductivities, transparency, and cost of graphite, the normal phase of carbon, are significantly different from those of diamond, the phase formed at elevated pressures and temperatures. In the quest for higher static pressures, researchers have been reducing the size of the pressure chamber, and hence the sample, to microscopic dimensions; this, in turn, necessitates the use of brighter light sources to "see" the sample in a reasonable time period.
Elemental and Phase Mapping of Sputtered Binary Plutonium Alloys
Authors: Wallace P. L. , Wien W. L. , Rizzo H. F. , Echeverria A. W. , Goehner R. P.
Published: March 2019

In this article, we demonstrate that the combination of elemental and phase mapping is a very powerful tool for characterizing sputtered, binary plutonium alloys.

A specially designed energy-dispersive spectrometer equipped with an automated x-y translational stage was used to measure elemental differences in several disks sputter-coated with binary plutonium alloys. Automated diffractometer scans were obtained from selected areas on the disks by using specially designed sample holders. The elemental differences were then correlated with the phases present and the observed corrosion resistance. The elemental spectra and diffractometer scans were analyzed using a modified version of the SPECPLOT program. This program enables the user to analyze both energy-dispersive elemental data and diffractometer data using a single program.
Industrial Applications of X-Ray Computed Tomography
Authors: Hunt P. K. , Engler P. , Friedman W. D.
Published: March 2019

Computed tomography (CT), commonly known as CAT scanning (computerized axial tomography), is a technology that produces an image of the internaI structure of a cross sectional slice through an object via the reconstruction of a matrix of X-ray attenuation coefficients. This non-destructive method is fast (50 ms to 7 min per image depending on the technological generation of the instrument) and requires minimal sample preparation. Images are generated from digital computations, and instruments essentially have a linear response. This allows quantitative estimations of density variations, dimensions and areas directly from console displays.
Grazing Incidence X-Ray Scattering Studies of Single Quantum Wells
Authors: Bates S. , Hatton P.D. , Lucas C.A. , Ryan T.W. , Miles S.J. , Tanner B.K.
Published: March 2019

X-ray scattering techniques at grazing incidence have been used to characterize single quantum well hetero–structures. Double–and triple-axis diffractometry has been used to determine lattice mismatch and layer thickness of a 250Å thick layer of AlInAs grown by MBE on an InP substrate and capped by a 45Å GaAs layer. Reflectivity measurements in the triple – crystal mode permit accurate measurement of individual layer thicknesses, relative electron density and interface roughnesses on the Angstrom level.
Oscillations in Interplanar Spacing Vs. sin2ψ a FEM Analysis
Authors: Noyan I. C. , Nguyen L. T.
Published: March 2019

Recent studies indicate that, if the stress/strain field within the irradiated volume in an x-ray stress determination experiment is inhomogeneous, oscillations occur in the interplanar spacing vs. sin2ψ plots. There is, however, little work on the degree of inhomogeneity required to cause a given oscillation, the uniqueness of the stress fields that can cause a given set of oscillations, or the error caused by applying the traditional methods currently in use to oscillatory data.

In this paper, numerical modeling and eiasto-plastic finite element analysis was used to determine the strain fields in the diffracting volume of a polycrystalline sample under load. The elastic strain fields obtained from the analysis were then averaged over the regions that would diffract in an x-ray experiment/and then correlated to x-ray strain data to obtain an idea of the problems described ahove.
Focusing Circle Errors in X-Ray Residual Stress Measurements of Nickel-Based Materials
Authors: Pardue E. B. S. , James M. R. , Hendricks R. W.
Published: March 2019

An unexplained anomalous sin2ψ split in x-ray stress measurements has consistently resulted from the use of Cr Kα radiation with nickel and austenitic stainless steels. Both, materials have diffraction peaks at low back-reflection angles for this radiation (nickel: 20 ⋍ 134°, austenitic stainless steel: 20 ⋍ 128°). The anomalous split is not evident when the measurements are made using Cr Kβ radiation, In an attempt to explain the errors produced by the Cr Kα radiation, focusing circle effects were analyzed and compared to experimental measurements made with both Cr Kα and Cr Kβ radiation on nickel-based samples,
A Comparison of Diffraction Elastic Constants of Steel Measured With X-Rays and Neutrons
Authors: Rudnik P. J. , Krawitz A. D. , Reichel D. G. , Cohen J. B.
Published: March 2019

The diffraction elastic constants have been measured for the 211 and 310 peaks of a high-strength, low-alloy ferritic steel using X-rays and neutrons. The X-ray measurements were performed using both a uniaxial tension and a bending device. The neutron measurements were performed using a uniaxial tensile device. Ten X-ray and four neutron measurements were made for each case. Statistical errors were calculated and compared with the standard deviations of the average values. In addition, neutron measurements were made for the 310 peak utilizing an interior probe volume.

The results indicate that the calculated statistical errors and the observed standard deviations were almost the same for each radiation. The X-ray and neutron tensile device measurements yielded similar results within experimental error. Furthermore, the X-ray tensile and bending results were similar as were the neutron internal volume measurements. These results suggest that near-surface X-ray measurements adequately sample the bulk material in the case of steel, and that different measurement techniques can be used to obtain reliable diffraction elastic constants.
X-Ray Diffraction Analysis of Fly ASH
Authors: McCarthy G.J. , Johansen D.M. , Steinwand S.J. , Thedchanamoorthy A.
Published: March 2019

Methods for, and results from, x-ray diffraction analysis of large numbers of fly ash samples obtained from U.S. power plants are described. Qualitative XRD indicates that low-calcium/Class F fly ash (usually derived from bituminous coal) consists typically of the crystalline phases quartz, mullite, hematite and magnetite in a matrix of aluminosilicate glass. Highcalcium fly ash (derived from low-rank coal) has a much more complex assemblage of crystalline phases that typically includes these four phases plus lime, periclase, anhydrite, alkali sulfates, tricalcium aluminate, dicalcium silicate, melilite, merwinlte and a sodalite-structure phase. Glass compositions among the particles are more heterogeneous and range from calcium aluminate to sodium calcium aluminosilicate, Every ash studied Is mixed with an internal Intensity standard (rutile) so that Intensity ratios can be used to make comparisons of the relative amounts of crystalline phases. An error analysis was performed to define the level of uncertainty in making these comparisons. These intensity ratios will be used for quantitative XRD phase analyses when reference intensity ratios for each fly ash phase become available.