bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation of the Distinct X-Ray Intensity Reaks Due to a Stacking Fault Structure in Plastically Deformed a-Brass
Authors: Sylwestrowicz W. D.
Published: March 2019

Distinct X-ray intensity peaks corresponding to a stacking fault structure have been observed in the plastically deformed ctbrass (30% Zn). TITO sets of intensity peaks were present simultaneously: one set corresponding to the f.c.c. structure of annealed a-brass, the second set was displaced with respect to the first set in accordance with the Paterson pattern for a stacking fault structure. With Increasing plastic deformation the height and width of the stacking fault peaks increased, while the height of f.c.c. peaks decreased. Finally, only the intensity peaks of the stacking fault structure were observed. The positions of the stacking fault peaks and the original structure peaks remained constant and were independent of the amount of plastic deformation.
A General Computer Program for Particle Size and Strain Analysis
Authors: Gazzara C. P. , Stiglich J. J. , Meyer F. P. , Hansen A. M.
Published: March 2019

A general computer program has been written in basic Fortran language and tested for computing average particle size, strain, and particle size distribution according to the Fourier method of B. E. Warren.

The program provides such optional features as input data and Fourier coefficient print out, automatic background correction, the choice of fixed count or fixed time input mode, the synthesized diffraction peaks deconvoluted with respect to the instrumental diffraction peak, and a variable amplification range of particle Size. Included in the analysis is a polynomial fitting procedure for the scattering factor. The authors have attempted to write this computer program to be as self-explanatory as possible for general applicability. This program is available on request.

This Fourier analysis program has been tested using known distribution functions, and has been used for measuring average particle size, particle size and strain distribution in heattreated boron-doped graphite samples.
Some Recent Work in Low Energy X-Ray and Electron Analysis
Authors: Henke Burton L. , Lent Robert E.
Published: March 2019

Research is being conducted on low energy x-ray and electron physics and application in the 100-1000 eV region. Work on the optimization of fluorescence analysis for light elements, including the development of efficient dispersive systems as the multilayer analysers of the Langmuir-Blodgett type, has been continued. Along with the ultrasoft x-ray program has been one on photoelectron and Auger electron spectroscopy. An evaluation of the application of low energy electron spectroscopy for surface characterization is being made.
X-Ray Spectroscopic Studies of Bonding in Iron Germanides
Authors: Adelson E. , Austin A. E.
Published: March 2019

X-ray emission spectra have been obtained with a single crystal spectrometer having a resolution λ/dλ of 6,640 for iron Kβ5 spectra. The spectrometer consisted of a Jarrel-Ash Microfocus unit in conjunction with a Picker diffractometer which was operated as a rocking crystal spectrometer with a stepping angle of 1/400th of a degree. Kβ5 and Kβ1,3 spectra have been obtained from iron, Fe0.9Mn0.9Ge, Fe1.60Ge, FeGe, FeGe2 and germanium. Because the K05 spectra are due to 4p - Is transitions from the 3d bands, the Kβ5 intensities are a direct measure of the overlap or hybridization of the 3d - 4s - 4p bands. The experimental results can be correlated either with orbitals derived on the basis of coordination, or more roughly with possible band distributions.
Portable X-Ray Fluorescence Analyzers and their use in an Underground Exploration Program for Tin
Authors: Springett Mark W.
Published: March 2019

In 1968 Consolidated Gold Fields commenced exploration below adit level at the Wheal Jane tin prospect in south-west England. During the surface exploration program the relatively recently introduced Portable X-ray Fluorescence Analyzer (“P.I.F.“) had been used for semi-quantitative scanning of drill core and for providing preliminary assays for tin on prepared core samples. The P.I.F. was introduced to the mining industry in 1965 (Bowie et. al. (1) and had originally been equipped specifically for tin analysis due to the current interest in tin exploration, the difficulties of chemically assaying for tin and the suitability of tin to X-ray analytical techniques. The instrumentation and principals of operation have been described by Bowie (1,2). At Wheal Jane the need to obtain rapid analyses to help control underground development and difficulties in visually recognizing the tin mineralization made the prospect an excellent testing ground for the practical aspects of the instrument.
In Situ Rock Analysis
Authors: Lantos J. , Litchinsky D.
Published: March 2019

Recent advances in solid state electronic circuitry and cryostat design have allowed the development of a low power consumption, fully portable XRF analyzer. The potential of such an instrument in geochemical surveying was investigated using the Inax 540 portable XRF pulse height analyzer/computer combined with the Inax 600 portable Si(Li) detector/dewar/LCD display. These two units comprise a total XRF analyzer and will determine and display the analyses of up to 36 elements simultaneously. Apart from providing a freshly exposed surface, no sample preparation is required.

Data illustrating the problems in the calibration of the unit for whole rock analysis are presented. Specifically data are presented on Uranium bearing rocks where the Uranium occurs along fracture lines in the medium. Results are compared with known assay and sampling problems are discussed.
Routine Energy Dispersive Analysis of Sulfur in Coal
Authors: Auermann R. , Russ J. C. , Shen R. B.
Published: March 2019

The analysis of sulfur in coal has been brought to the attention of the general public in recent years primarily as it concerns the pollution problem with coal-fired electric generation. Although our application is different, some of the results would be equally applicable to that circumstance. The Cement Division of Florida Mining and Materials Corporation produces annually about 500,000 tons of both Portland and Pozzolanic cements, using a coal-fired rotary kiln. The sulfur content of coal used in the manufacture of clinker ranges from traces to as much as 6%. Sulfur content in a dry process plant such as ours (this is the modern energy-efficient type of cement plant) is very critical, and in our case must be limited to 1.2% max.
Application of the Fundamental Parameters Model to Energy-Dispersive X-Ray Fluorescence Analysis of Complex Silicates
Authors: Dalheim Peggy
Published: March 2019

The elemental analysis of geologic samples such as rocks, minerals and coal ash is a complicated task because of their wide, complex compositional range. Energy dispersive x-ray fluorescence (EDXRF) can provide a rapid, accurate and precise way of analyzing geologic samples. Two approaches to reducing EDXRF intensity data to elemental concentrations are the empirical approach and the fundamental parameters (theoretical) approach. Empirical methods require numerous standards within restricted compositional ranges so can become complex, time consuming and, therefore, expensive if diverse suites of samples are to be analyzed for many elements. Fundamental parameters, on the other hand, requires knowledge of physical constants such as mass absorption coefficients, jump ratios and fluorescent yields, and only one matrix independent standard to calculate a calibration constant for each element making it an ideal approach to the analysis of diverse geologic samples.
The Fast Analysis of Uranium Ore by EDXRF
Authors: Vane Ronald A. , Stewart William D. , Barker Mike
Published: March 2019

Energy dispersive X-ray fluorescence (EDXRF) spectrometry has been applied to the high speed analysis of uranium ore for the purpose of grading and sorting truckloads of ore at the mine. The system is able to analyze uranium ore in less than 60 seconds with uranium levels ranging from < 0.005% to > 5% U3O8. Precision at the 2σ level for 200 ppm ore is better than 10% relative. Good agreement is obtained with wet chemical results in a large variety of rock matrices.
Fundamental-Parameters Calculations on a Laboratory Microcomputer
Authors: Criss J. W.
Published: March 2019

Fundamental-parameters calculations can be made on a laboratory microcomputer fo r automatic treatment of interelement absorption and enhancement effects in x-ray fluorescence analysis. A new software package, called XRF-11, uses an efficient combination of fundamental parameters and alpha factors to compensate for any lack of measured reference materials, while taking full advantage of whatever standards are available, even just pure elements. In many cases, one multi-element standard is enough for accurate analysis.

The new XRF-11 software uses the same data base of absorption coefficients, fluorescence yields, etc. as the big-computer program NRLXRF, and combines theory with experiment in a consis tent way that is similar to, but more efficient than, the treatment used in NRLXRF.
Modified NRLXRF Program for Energy Dispersive X-Ray Fluorescence Analysis
Authors: Shen R.B. , Criss J. , Russ J.C. , Sandborg A.O.
Published: March 2019

An X-ray fluorescence program, similar to NRLXRF2 has been written by John Criss to fit into the DEC LSI-11 32K computer with floppy disk system. EDAX has combined the new version with our own software to create a set of FORTRAN programs, called “XRAY 95” to use with the new EDAX EXAM 9500 energy dispersive X-ray fluorescence system. The XRAY 95 program employs both fundamental-parameter equations and influence coefficient equations to optimize the matrix corrections for multicomponent samples. It is an extremely versatile program, using whatever reference standards the user provides and supplementing them with physical theory. The result is a practical approach to fast, accurate analysis.
Monte Carlo Simulation of Sample Scattering Effects from Homogeneous Samples Excited by Monoenergetic Photons
Authors: Doster J. M. , Gardner R. P.
Published: March 2019

The error introduced by sample scattering in EDXRF analysis is evaluated by Monte Carlo simulation. This is accomplished by deriving a Monte Carlo model capable of simulating single Compton and Rayleigh scatters from the exciting photon source and from fluorescent X rays in homogeneous samples. The model also includes primary, secondary, and tertiary fluorescence events. (1) Results are given for Ni-Fe-Cr ternary samples for various exciting energies with and without scattering and indicate that errors as large as 2% can be attributed to this effect.
The Application of Digital Filters to the Analysis of Ge and Si(Li) Detector X-Ray Spectra
Authors: Rayburn L. A.
Published: March 2019

One of the uncertain aspects in the analysis of x-ray spectra is the determination of the proper background to subtract from the raw data. In those cases where the background is a smoothly varying funct ion of the x-ray energy, the application of a digital filter to the raw data will effectively remove the background leaving only the filtered peak information. These filtered peaks can then be fit by using a non-linear least squares method in conjunction with a suitably chosen mathematical model of the peak structure.
Direct Determination of Niobium in Uranium-Niobium Alloys
Authors: Long Jack L.
Published: March 2019

A procedure for determining niobium in uranium-niobium binary alloys was developed. The procedure requires only that a compact be made by pressing turnings, and wet chemical treatment is avoided entirely. By eliminating the wet chemistry, time is reduced by a factor of at least three compared with previous practice.

Standardization was accomplished by separating each batch of machined turnings from specially cast uranium-niobium alloys into individual strands. A composite portion of each strand was analyzed for niobium by wet chemistry. The balance of the turnings from each batchy was pressed into a compact. Seven standard compacts resulted. The average Intensity ratio of niobium-to-uranium vs. the percent niobium for fourteen determinations on each standard compact was used to calculate a correlation coefficient of 0.999.

The standard deviation of the Intensity ratios between duplicate compacts (average of 52 samples) was less than the standard deviation found between aqueous duplicates (average 125 samples) by a factor of 4.
The Effective use of Filters with Direct Excitation of EDXRF
Authors: Vane Ronald A. , Stewart William D.
Published: March 2019

Primary beam transmission filters in energy dispersive X-ray fluorescence (EDXRF) analysis are used to shape the spectral output of the X-ray tube. The effective use of these filters allows the optimization of excitation conditions for each different analysis. Filters are used in two basic ways in EDXRF; either as edge filters or as white filters. The proper choice of filter and excitation conditions optimizes the analysis of a particular element or spectral region by shaping the primary radiation to reduce background and to maximize excitation.
Fracture Surface Analysis of Ball Bearing Steel by X-Ray Residual Stress Measurement
Authors: Nakashima Hirokazu , Tsushima Noriyuki , Muro Hiroshi
Published: March 2019

Plastic deformation necessarily accompanies fracture even in high hardness steels such as ball bearing steel, though it is within a very shallow layer just under the fracture surface. The depth of the plastic deformation zone can he determined by X-ray measurement of half value breadth. However, in the case of high hardness steel, the half value breadth is not changed significantly by this kind of plastic deformation. On the contrary, residual stress on the fractured surface was found to change remarkably depending on the mode of fracture such as static, fatigue or delayed types.
Stress Analysis in Graphite/EPOXY
Authors: Barrett C. S. , Predecki Paul
Published: March 2019

X-rays can be used to measure residual as well as applied stresses in polymers and reinforced polymeric composites, by diffracting from filler particles that are embedded before curing. We have investigated various fillers that exhibit suitable stress induced shifts of diffraction angle when embedded in uniaxial graphite fiber/epoxy composites. X-ray measurements of elastic strains in the particles are proportional to the corresponding composite strains, in agreement with the model of H. T. Hahn. Results indicate that the stress sensitivity (change in X-ray diffraction angle per MPa applied to the composite) increases in the order W, CdO, Hi, Ag, Nb, Al. With Al 333 + 511 reflections of CuKα1, the diffraction angle shifts 8.52 x 10-4deg 2θ per MPa. Theoretical predictions are in reasonable agreement with this figure. The elastic range terminates at a yield point beyond which little or no further shift of the diffracted beams is seen for metallic fillers, but no such yield point has appeared with CdO particles. Oppositely directed shifts are seen after unloading from stress levels that have exceeded the yield point.
Nanosecond Time Resolved X-Ray Diagnostics of Relativistic Electron Beam Initiated Events*
Authors: Kuswa Glenn W. , Chang James
Published: March 2019

The dynamic behavior of a test sample during and shortly after it has been irradiated by an intense relativistic electron beam (REB) is of great interest to the study of beam energy deposition. Since the sample densities are far beyond the cutoff in the optical region, flash x-radiography techniques have been developed to diagnose the evolution of the samples. The conventional approach of analyzing the dynamic behavior of solid densities utilizes one or more short x-ray bursts to record images on photographic emulsion. This technique is not useful in the presence of the intense x-rays from the REB interacting with the sample. We report two techniques for isolating the film package from the REB x-ray pulse.

One arrangement employs a microchannel plate electron multiplier array (CEMA) to convert the incident x-ray linage to an amplified electron “image,” This image is proximity focused onto an aluminized plastic scintillator held at 5-10 kV relative to the CEMA output face. A streak camera shielded from the x-rays is used to record the time varying image on the 2 ns persistence scintillator. The resolution limitation is primarily that of the image converter, i.e., 5 ns and 5 line pairs/mm.

To achieve higher sensitivity and resolution, an arrangement employing two microchannel plates has been developed. In this device, two channel plates are immersed in a long uniform solenoidal magnetic field; the electrons generated by the first plate are guided by the magnetic field lines to the second plate which increases the system gain by > 103. Placed a few mm behind the second plate is a phosphor screen which in turn is directly connected to film via a fiber optic face plate. In this way, isolation of the x-ray burst from the long persistence phosphor and film is achieved by using a long solenoid. The temporal resolution (approximately 3 ns) can be gained by the appropriate gating of the channeltron plates and/or grids. The spatial resolution is governed by the channel plate “pores” size, by electron orbit characteristics in the solenoidal magnetic field, and by the effective x-ray source geometry.

By using these two methods, nanosecond time resolved x-ray pinhole photographs and flash x-ray radiograph of REB initiated events have been achieved.
X-Ray Diagnostics of Laser Produced Plasmas Using CaF2 (Dy) Thermoluminescent Dosimeters
Authors: Mayer F. J. , Montry G. R. , Benn E.
Published: March 2019

The use of CaF2 (Dy) thermoluminescent dosimeters to diagnose the X-radiation from 1.06 μ laser-produced plasmas is described. The TLD's have been used in various cassettes to measure total X-ray yield and the X-ray continuum out to ∼100 kev. Described are experiments pertaining to maintenance and recovery of TLD soft X-ray response, their linearity, insensitivity to 1.06 μ laser light, and energy calibration. Also, described are the TLD attenuation experiments in the “soft” and “hard” components of the laser plasma X-ray spectrum.
Application of Heavy Charged Particle Induced X-Ray Emission to the Trace Element Analysis of Human Tissue and Blood Serum
Authors: Watson R. L. , McNeal C. J. , Jenson F. E.
Published: March 2019

Measurements of peak-to-background ratios for K x-ray production by 1.7 MeV/amu protons, alpha particles, carbon ions, and neon ions have been carried out for the purpose of determining the optimum projectile atomic number for particle induced x-ray emission analysis. The feasibility of applying the method to the trace element analysis of thick samples of tissue and blood serum has been explored.
A Computer Control for an X-Ray Fluorescence Analysis Unit
Authors: Artz B. E. , Kelly Carol J. , Short M. A.
Published: March 2019

An X-ray fluorescence analysis unit has been automated with a multi-position sample changer, a stepping motor to position the spectrometer, and computer addressable switches to control the selection of crystal, detector, collimator, and beam filter. The unit can be controlled off-line through a Teletype or on-line with a computer. This computer utilizes a multi-user program for the simultaneous operation of the fluorescence analysis unit and two diffractometers. Programming the system for any desired analytical or research procedure is accomplished using an expanded version of BASIC.
Semi-Quantitative Determination of Asbestiform Amphibole Mineral Concentrations in Western Lake Superior Water Samples
Authors: Cook P. M.
Published: March 2019

The amphibole mineral, cummingtonite-grunerite, has been used as a tracer for taconite tailings discharged into Western Lake Superior. The discovery of many asbestiform amphibole fibers in the tailings and Western Lake Superior water lead to concern over fiber concentrations in municipal water supplies using this water. This concern was based on the association between human asbestos exposure and increased rates of cancer of the gastrointestinal tract and peritoneum. An x-ray diffraction external standard technique has been developed for rapid, inexpensive, semi-quantitative determinations of amphibole mass concentration in water. The average amphibole mass concentrations for different Western Lake Superior water intakes compare very well with the average electron microscope fiber counts for the same samples. Daily amphibole analysis of the Duluth water supply indicates an average amphibole concentration of 0.19 milligrams per liter.
Application of the Rietveld Method for Structure Refinement with Powder Diffraction Data
Authors: Young R.A. , Wiles D.B.
Published: March 2019

The object of the Rietveld method is to produce refined values of crystal structural parameters from powder diffraction data. Many materials of great interest can not be made available for study in single crystal form. This may be because it is not possible to prepare a single-crystal form at all (e.g., human tooth enamel) or because the single-crystal form differs from the polycrystalline form with the properties of interest (e.g., catalysts). Thus, our basic understanding of the atomic scale mechanisms is limited on the structural side by the information that can be deduced from powder diffraction patterns. (Only diffraction and EXAFS are direct probes of the spatial arrangements of atoms.) The Rietveld method has greatly extended the amount of structural detail that we can obtain routinely from powder diffraction patterns. In this method, structural parameters such as atom coordinate, thermal motion, and site occupancy parameters are adjusted in a least-squares refinement procedure until the best fit is obtained between entire calculated and observed powder diffraction patterns, as a whole.
Porotectosilicate Structure Determination from Model Building
Authors: Kokotailo George T. , Schlenker John L.
Published: March 2019

Porotectosilicates are a class of siliceous crystalline materials which includes both zeolites and materials which resemble zeolites in crystal structure, but may or may not have ion exchange capability. The framework structures of these porotectosilicates are comprised of “T” atoms tetrahedrally coordinated to oxygen, where “T” can be Al, Si or any other element capable of isomorphous substitution for silicon. The occurrence of small crystals and the additional problems introduced by the presence of stacking faults and crystal twinning make structure determination of porotectosilicates by conventional approaches difficult.

The industrial significance of these materials has led to the development of a technique which permits the determination of their structure. The method involves the construction of appropriate hypothetical models, a DLS refinement followed by computation of a Smith plot for comparison with the experimental powder pattern. Model crystal structures may now be refined using the Rietveld technique. It is expected that this technique will contribute significantly to the solution of porotectosilicate structures which are difficult--if not impossible--to establish by other techniques.
X-Ray Powder Diffraction in Europe
Authors: de Vries J. L. , Philips N. V.
Published: March 2019

Talking about X-Ray Diffraction in Europe, I'll limit myself to personal experiences. I started with XRD in Amsterdam University, namely structure analysis, but as well powder diffraction for identification of minerals, determination of crystallinity of stretched gelatine and many more such applications. Exclusively, cameras with photographic recording were used, and they are still used in Europe, to a great extent; maybe in 30-40% of all cases. We used a mechanical rectifier controlled by an adjustable spark gap. This system worked fine, till our laboratory cat decided to sniff at the sparks! That was the end of our generator and the cat. The powder samples in our D.S. cameras, mostly glued onto glass fibers were rotated during exposure. As we could not afford small motors, the rotation was done by blowing air against a windmill system mounted on the sample holder. A typical Dutch solution.
The Use and Accuracy of Continuously Scanning Position-Sensitive Detector Data in X-Ray Powder Diffraction
Authors: Göbel Herbert E.
Published: March 2019

By collecting the diffracted X-rays in a focussing powder diffractometer with a linear position-sensitive detector (PSD), the data accumulation time can be widely reduced. Due to the focussing properties of the geometrical arrangement good resolution can be simultaneously achieved over a few degrees of the diffraction angle 2 Theta. The full pattern is collected by scanning the PSD along the entire 2 Theta arc. Scanning speeds of several hundred degrees per minute are possible and still yield well plotted diagrams.

This work demonstrates the performance of the system in different tasks of X-ray powder diffraction such as identification of unknown materials, quantitative analysis, determination of lattice constants and microcrystalline properties. The results, evaluated by parts of the program system DIFFRAC 11, show that the accuracy and resolution of the continuously scanning PSD technique match these tasks without difficulty and reach the precision limits of powder diffractometry itself. It is demonstrated that the data collection velocity, which matches well the data evaluation times, is not the only advantage compared to conventional diffractometets.
Use of a Position Sensitive Detector
Authors: Lebrun J. L. , Sprauel J. M. , Maeder G.
Published: March 2019

Our goniometer used is a classical one with step scanning motors both on θ and 2θ movements. The theoretical radius is 250 mm but it can be changed easily.

Two kinds of PSD have been used, the older one of a resistive type with a carbon coated quartz fiber and, for this year, a capacitive one with a gold-plated molybdenum wire anode, which is more reliable, with a very good pulse height analyser. It is connected to a 48K calculator (IN 90) with a floppy disk unit. A special interface has been made which is able to drive separately the 2θ and θ movements of the goniometer, using the output signals of the calculator. After the different settings of the goniometer and the initialization of the positions in 9 and 26, every movement can be ordered either by a very simple software from the keyboard or inside a more complex program.
A High-Speed Signal Processor Using a Digital Divider for Position Sensitive Proportional Counters
Authors: Kobashi S. , Mochiki K. , Hasegawa K. , Sekiguchi A. , Hashizume H. , Yoshioka Y.
Published: March 2019

Most position sensitive proportional counters (PSPCs) currently used in X-ray diffraction experiments have a dead time longer than 5 μs. Though such PSPCs are useful in measuring weak diffraction diagrams, a faster counter is needed to detect strong X-ray diagrams produced with synchrotron radiation sources. The long dead time of PSPCs using a charge division position read-out is due to the slow analog division circuit plus analog-to-digital converter employed in the present system. A fast processor can be built utilising two high-speed ADCs to digitize voltage signals from the detector, followed by a digital divider to compute position of detected photons. The present paper describes the design of such a processor and some preliminary testings of its performances.
An X-Ray Study of Ion-Implanted Liquid Phase Epitaxial Garnet Films with a Single Crystal Dirfractometer
Authors: Wang Po-wen , Ju Kochan , Huang T. C.
Published: March 2019

A vertical scanning single crystal diffractometer with graphite monochromator and narrow divergent beam controlled by an IBM Series/1 computer was used to study crystal damage in the ion-implanted garnet films including strain effects induced by multi-implantation processes as a function of the types of ions, their energies and doses, growth and annealing temperatures.
Residual Stress Change Due to Rolling Contact of Ball and Roller Bearings
Authors: Maeda Kikuo , Tsushima Noriyuki , Muro Hiroshi
Published: March 2019

The life of a rolling bearing is predominantly determined by the contact stress between the rolling elements (ball and roller) and the raceway of inner and outer rings. The contact stress is calculated by assuming Hertzian stress distribution. The maximum Hertzian contact stress Pmax usually ranges from 2000 to 3000 MPa in actual service of rolling bearings. These figures are rather large compared to the compressive yield strength of hardened bearing steel (σys = 2000 MPa). Therefore plastic deformation sometimes occurs under the raceway, creating residual compressive stress. Several investigators have so far reported about the residual stress due to rolling contact. There were, however, few who referred to the residual stress in used bearings and application of residual stress measurement to failure analysis.
Energy-Dispersive Diffraction Analysis of the Structure of Metallic Glasses
Authors: Wagner C.N.J. , Lee D. , Tai S. , Keller L.
Published: March 2019

The intensities of x-rays scattered by amorphous Fe80P13C7 and Fe40Ni40P14B6 samples have been measured as a function of photon energies E at fixed scattering angles 2θi using a Li-drifted Si detector and polychromatic x-rays generated by a 50KV full-wave rectified generator. The coherently scattered intensity per atom was calculated for free-standing samples as well as samples contained in a Be or pyrolytic graphite cell, after the evaluation of the energy dependence of the primary beam spectrum by an iterative process. The interference functions were then calculated from the data obtained in transmission and reflection, and compared with those measured with the conventional variable 2θ technique. Good agreement between energy-dispersive diffraction (also called variable wavelength technique) and variable 2θ diffraction was observed in all cases.
Experimental Evaluation of Peak Height Approximation for X-Ray Diffracted Integrated Intensity Method
Authors: Gazzara Charles P.
Published: March 2019

The mathematical description of an X-ray peak, diffracted from a powder or polycrystalline material, using physically meaningful parameters has been of interest for many years. With the popularity of computers, this need to characterize a diffraction peak has intensified.

A key problem which persists is how to describe the instrumental diffracted profile and therefore the observed diffracted characteristic peak with subsequent combinations of Kα doublets and mixed overlapping peaks. Many attempts have been made at finding a “true“ function to fit the observed diffracted peak; however, a practical solution has yet to be found.
On Stream Analysis of Lead and Zinc Ore Fractions Using Energy Dispersive and Wavelength Dispersive Techniques
Authors: Kawatra S. K. , Dalton J. L.
Published: March 2019

On-line X-ray fluorescence analysis is used in the mineral processing industry to monitor the composition of the solids contained in various slurry streams. This study compares wavelength dispersive and energy dispersive techniques by using a slurry recirculation system employing both an X-ray tube excitation-wavelength dispersive system, and an isotope-excitation energy dispersive system. The results showed the less costly energy dispersive system yields accurate information that can be used to control milling operations.
A General Method of Blank Subtraction for Quantitative X-Ray Fluorescence Intensity Measurements
Authors: Quinn Alan P.
Published: March 2019

Residual analyte intensity exists in a spectrometer when, for example, the x-ray source is contaminated with the analyte. A blank specimen, identical to the sample but devoid of the analyte, may be used to determine this residual analyte intensity, and, thereby, allow quantification of that intensity due to analyte in the sample. It is generally considered that a single pure material could serve as a blank for many analytes in many matrices. In practice, at least for low average atomic number matrices such as glasses, the reflectivity of similar samples may differ substantially, rendering inaccurate this simple blank subtraction. In such cases a blank is needed for each sample, where the reflectivity of the blank is matched to that of the sample. In order to eliminate the need for generation of blanks to match each of the samples, a general method to quantify the net residual analyte intensity as a function of specimen reflectivity by measurement of two pure material blanks is proposed herein.
Erroneous Peaks in Energy Dispersive X-Ray Spectra
Authors: Russ J. C.
Published: March 2019

The necessary first step in using an x-ray fluorescence spectrometer for quantitative analysis is to obtain the intensities for the various elements. With a wavelength dispersive system this usually requires simply setting the crystal to the proper angle (and possibly adjusting the pulse height selector) and making a dead-time correction. With the energy dispersive x-ray fluorescence analyzer it is necessary to take into account the presence of erroneous peaks in the spectrum, to obtain true intensity values.

False peaks due to diffraction of white tube radiation from the sample can usually be shifted to portions of the energy spectrum where they do not interfere with emission lines of interest by selection of the proper tube-sample-detector geometry. Modern amplifier design provides a built – in dead time correction and greatly reduces the effects of pulse-pile-up, although the latter phenomenon will still produce small peaks at exact multiples of major peaks.
Model, Equations, and Correcting Factors for the X-Ray Fluorescence Analysis of Geological Material
Authors: Pablo Galán Liberto de
Published: March 2019

A procedure is presented for the chemical analysis of rocks by x-ray fluorescence. Rocks are grouped within a set of twelve empirical standard compositions, prepared by sintering to 1200°C appropriate mixes of minerals and chemicals. For the major rock components silica, alumina, calcia, magnesia, potash, and ferric oxide, and the trace elements silver, copper, lead, zinc, molybdenum, manganese, tin, and antimony, quadratic equations are derived correlating concentration and intensity ratios corrected for dead time, background, and equipment drift. Interelemental effects are computed as a series of correcting factors modifying the basic analytical equations.
An Investigation of the Correlation Between Human Diseases and Trace Element Levels by Proton-Induced X-Ray Emission Analysis
Authors: Lear R. D. , Van Rinsvelt H. A. , Adams W. R.
Published: March 2019

The proton beam from the 4 MV Van de Graaff at the University of Florida has been used in conjunction with a 5 mm thick lithium drifted silicon, Si (Li), x-ray detector to do elemental analysis of biomedical samples by proton-induced x-ray emission (PIXE). Several hundred samples, mostly autopsy organs ashed at high, temperature, have been analyzed by this method. The main object of the research is the correlation between human diseases and trace element levels. The target mass has been determined by monitoring the elastically scattered protons from the sample. This technique considerably reduces the target preparation time by eliminating careful weighings or doping of each individual sample.
The Effects of Errors on the Convergence of an Iterative Deconvolution Method
Authors: Madden H. H. , Houston J. E.
Published: March 2019

Calculations carried out to investigate the van Cittert iterative deconvolution method and the effects of random noise and truncation errors on its convergence behavior are presented. Gaussian functions are used for "both the true function W and the system, response function A. The model "observed" function S is generated from W and A. Both rms differences between the result of n iterations Wn and the true function, and between Wn*A and S are used to measure convergence. The effects of introducing errors can be measured against standards set by the convergence without such errors. These "no-error" calculations make use of true functions with widths from 2.0 to 0.67 times the response function width. The effects of random noise are investigated by adding noise to W*A before deconvolution. A small amount of random noise initially added builds up rapidly in amplitude during the iterative process and eventually dominates the rms difference calculations. To suppress the effects of random noise build-up; smoothing techniques are applied, the best of which involved smoothing both the noisy observed function, S, and the system response function, A, before deconvolution. The smoothing operation is thus taken as part of the measurement and. the divergence resulting from, the noise build-up is avoided. The results depend strongly upon, the -width of the smoothing function. Uhsymmetric system response functions, similar' to those encountered in soft x-ray appearance potential spectroscopy and in x-ray continuum, isochromat measurements, are used in investigations of truncation errors. Abrupt cut-offs of the model S and A functions before deconvolution result in the build-up of large fluctuations in W . These truncation errors become increasingly localized with continued iterations and make only minor contributions to the errors in Wn in the vicinity of the real peak if the truncations are made sufficiently far from the peak location. Alternatively, the truncation errors can be avoided by analytical continuation.
Predicting some Effects of Lattice Vibrations on Proton Scattering Patterns
Authors: Barrett C. S.
Published: March 2019

A method of predicting the approximate relative intensities of lines in proton blocking patterns recently proposed, which is based on summing the squares of structure factors for the various orders of reflection of a plane, is found to predict certain effects of lattice vibrations on the lines in some recently reported patterns. The mean square amplitude of vibration enters the calculations through a Debye-Waller temperature factor like that used in X-ray diffraction. When patterns are compared for groups of crystals that are nearly identical except for this temperature factor, the qualitative predictions by this method agree with the observations. If it is also arbitrarily assumed that the integrated intensity dip at a spot where lines intersect is approximated by summing the calculated Integrated intensity dips for all of the lines crossing at the spot, one has a simple and convenient method of predicting relative spot intensities. Such calculations have been successful in establishing the order of decreasing intensity for most of the spots along a given line, with several different kinds of crystals. This method also serves to predict qualitatively how prominent the spots appear relative to the lines, in general, in patterns of crystals that differ appreciably only in the amplitude of the thermal vibrations.
Errors in Residual Stress Measurements due to Random Counting Statistics
Authors: Kelly C. J. , Short M. A.
Published: March 2019

The measurement of residual stress, using X-ray diffraction techniques, is based on the change in diffraction angle determined for the Intensity maximum of some suitable reflection from the sample when this is placed consecutively with its surface at two different angles to the diffracting planes. These diffraction angles may be obtained in a variety of ways, but are most often calculated from measurements of three X-ray diffraction intensities at angles selected in the immediate vicinity of the peak maximum at each sample angle and fitting each set of data to a parabolic curve. A simple mathematical expression may be derived relating the diffraction angles, and hence the residual stress, to the measured X-ray intensities; there will, however, be statistical errors in the calculated diffraction angles due to random counting errors in the measurement of the X-ray diffraction intensities. From the expression relating the residual stress to the X-ray intensities an equation has been derived giving the standard deviation in the residual stress due to random counting errors. In addition, a simple approximation has been obtained from this equation showing that the standard deviation is decreased by increasing the number of counts accumulated for each X-ray intensity measurement and by increasing the size of the angular increments between the data points. It will also be shown that, using the approximation, it is possible to estimate in advance the number of accumulated counts at each point necessary to attain a desired standard deviation in a residual stress measurement.
Variable Step-Counting Times for Rietveld Analysis, or, Getting the Most Out of Your Experiment Time
Authors: Madsen I.C. , Hill R.J.
Published: March 2019

The magnitudes of the peak intensities in a powder diffraction pattern are not uniformly distributed as a function of diffraction angle. The Lorentz-polarization factor, X-ray form-factor and the thermal vibration parameters all conspire to progressively decrease the intensities of the peaks as sinθ/λ increases. In spite of this, diffraction data for Rietveld analysis is universally collected using the same counting time for each step in the pattern. As a result, peaks at high angles are collected with lower counting precision than those at low angles, despite the fact that the high-angle region has a higher density of peaks and therefore contains more information than the low-angle part of the pattern. Indeed, the intensity, position and profile of reflections at medium and high sinθ/λ are often more easily modelled since they are subject to less interference from systematic effects such as extinction, specimen transparency and α1/α2 overlap errors. In the present work a novel variable step-counting-time regime has been devised that increases the counting times with diffraction angle in a manner inversely proportional to the intensity fall-off calculated from the Lorentz-polarization, form-factor and thermal parameters. The effect of this new data collection regime on the results of Rietveld refinement of a number of materials of varying structural complexity is discussed.
Electron Density Distribution Obtained from X-Ray Powder Data by the Maximum Entropy Method
Authors: Sakata Makoto , Takata Masaki , Kubota Yoshiki , Uno Tatsuya , Kuhazawa Shintaro , Howard Christopher J.
Published: March 2019

The electron density distribution maps for CaF2 and TiO2 (rutile) were obtained from profile fitting of powder diffraction data by a Maximum Entropy Method (MEM) analysis. The resultant electron density maps show clearly the nature of the chemical bonding. In order to interpret the results, the nuclear density distribution was also obtained for rutile from powder neutron diffraction data. In the electron density map for rutile obtained by HEM analysis from the X-ray data, both apical and equatorial bonding can be seen. On the other hand, the nuclear density of rutile Is very simple and shows the thermal vibration of nuclei.
A Multi-Line Standardless Method for X-Ray Powder Diffraction Phase Analysis
Authors: Li D.Y. , O'Connor B.H.
Published: March 2019

Quantitative phase analysis (QPA) methods which employ only one diffraction line for each phase arc generally unreliable due to the influence of systematic errors such as preferred orientation and extinction. Gazzara and Messier (1977) proposed a multi-line QPA method using normalised line intensities for line j of phase i,

where Iij = measured Bragg intensity, m = multiplicity, Lp = Lorentz-polarisation factor, |F| = structure amplitude and Vi = cell volume. The method proposed here is a refinement of the Gazzara-Messier procedure. Phase compositions are calculated directly from the mean normalised Intensity for resolved lines which span the 2θ range of the instrument. The method makes use of the variance in to estimate standard deviations for the phase compositions. Test results are given for binaries of corundum-quartz and corundum-ceria.
Characterization of Epitaxial High Tc Superconductors using a Parallel Beam X-Ray Diffractometer
Authors: Houtman E. , Ryan T.W. , David B. , Doormann V.
Published: March 2019

Many analytical problems cannot be solved using a single XRD measurement. One example is the epitaxial growth of thin films of High Tc superconductors. To fully characterise such a sample it is necessary to study both the orientation (texture) and the phase composition of the layer.
X-Ray Texture Measurement Using a Position Sensitive Detector
Authors: Wcislak L. , Bunge H.J. , Haase M. , Nauer-Gerhardt C.
Published: March 2019

For pole figure measurement the flat sample has to be tilted which leads to peak broadening and peak overlap in peak-reach diffraction spectra. Using a linear position sensitive detector /PSD/, complete diffraction spectra can be obtained in each sample orientation. Peak separation can then be done by Gaussian fitting. When measuring with a PSD, each diffraction peak corresponds to a particular diffraction vector. This has to be taken into consideration by a coordinate transformation. The PSD-method is the only practical method of texture measurement for materials with complex diffraction spectra.
Introduction of a Nist Instrument Sensitivity Standard Reference Material for X-Ray Powder Diffraction
Authors: Cline James P. , Schiller Susannah B. , Jenkins Ron
Published: March 2019

Improvements in sample preparation methods have resulted in increased accuracy in x-ray powder diffraction intensity measurements. This improvement has focused scrutiny on the instrument as a potential source of error. NIST Standard Reference Material, SRM, 1976 consists of a sintered α alumina, corundum, plate certified with respect to 12 relative intensity values from 25 to 145 degrees 2θ. Its function is to allow for standardization of powder diffraction intensity as a function of 2θ angle (instrument sensitivity). An increase in the accuracy of interlaboratory comparisons of diffraction intensity and related determinations will result. Utilization of the SRM requires the user to collect intensity data from the test instrument in a manner which conforms to that used in the certification. Graphical interpretation of the ratio of these data to those on the certificate will allow for appropriate judgment as to the condition of the test instrument. Discontinuities in the data indicate a malfunctioning or misaligned instrument. Systematic bias, introduced by design characteristics of the test instrument, manifests itself in terms of a pattern in the data other than a horizontal straight line with value of one. This bias may be removed with the calculation and application of a correction curve.
Application of Imaging Plate for X-Ray Diffractometry
Authors: Shibata Atsushi , Sasaki Katsunari , Kinefuchi Takao
Published: March 2019

The Fuji Imaging Plate (IP) is a 2-dimensional detector in which a latent X-ray image is stored as a distribution of color centers on a photostimulable phosphor (BaFBr:Eu2+) screen. It has a large effective area, wide dynamic range and high sensitivity. Thus it has been widely used not only in medical but also in scientific and industrial fields. Particularly in X-ray structure analysis, mainly of proteins, it has been used extensively and achieved good results.

On the other hand, few applications have been reported in the field except for structure analysis, in spite of the superior performance of the IP which will give significant advantages in various measurements which have been done using an X-ray film such as electric device and fiber specimen.

Therefore we report here the basic performance of R-AXIS II(Rigaku Automated X-Ray Imaging System II), an IP reader made by Rigaku, and some applications of X-ray diffraction measurements using IP.