bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison of Energy Dispersive XRF To AA for Specific Metals in Natural Waters
Authors: Smith F. C. , Masi O. H.
Published: March 2019

The growing need for multielement analytical capability is currently being emphasized by the ever broadening governmental regulations on metallic pollutants in water sources. These new regulations cover more elements and are more restrictive in the type and amounts allowable in waste water and natural sources. For example, the California Public Health Law of 1970 states that 0.01 ppm arsenic, 1.0 ppm barium, 0.01 cadmium, 0.05 ppm manganese and 5.0 ppm zinc are the limiting concentrations of these elements in drinking water. Monitoring programs, both for compliance-enforcement and general survey work, have become a greater burden on both governmental agencies and private inductries. While trace analysis in solutions presents certain difficulties to the analytical chemist, regardless of the technique used, the results of this study indicate that x-ray analysis provides a more useful analytical tool for routine work and offers multielement capability with minimal sample preparation.
Calibration of an Energy Dispersive X-Ray Fluorescence Spectrometer
Authors: Stiles A. R. , Dzubay T. G. , Baum R. M. , Walter R. L. , Willis R. D. , Moore L. J. , Garner E. L. , Gramlich J. W. , Machlan L. A.
Published: March 2019

The purpose of this work was to develop accurate calibration standards which were fully characterized in terms of uniformity and concentration using fundamental measuring methods. Three similar sets of vacuum deposits were commercially made, each set containing the single deposits CuS, KCl, CaF2, Cr, Fe, Cu, RbNO3, SrF2, MoO3 , BaF2, and Pb. Thickness variations in each deposit were measured with PIXEA (proton induced x-ray excitation analysis) measurements taken at 6 to 8 positions along the deposit diameters. Relative elemental concentrations on corresponding deposits from each set were measured using multiple XRF intercomparisons. One set of deposits was destructively analyzed at the National Bureau of Standards with isotope dilution thermal ionization mass spectrometry (IDMS) in order to calibrate the remaining sets of vacuum deposits. The calibrated deposits were compared with standards from two commercial sources. For seven elements heavier than chlorine there was an average deviation of 13.5% between the calibrated deposits and the commercial standards. Disagreements as large as 15% were observed between standards from the two commercial suppliers.
Medical Applications of a Small Sample X-Ray Fluorescence System
Authors: Alfrey A. C. , Nunnelley L. L. , Rudolph H. , Smythe W. R.
Published: March 2019

A quantitative x-ray fluorescence (XRF) analytical system has been developed with the emphasis on small sample size. The system employs a two kilowatt tungsten anode x-ray tube, and an 80 mm2 lithium drifted silicon x-ray detector arranged in a compact geometry. Operation at 55 kV and 20 m A give a sensitivity of 153 counts/min/ng at Z=42 (molybdenum). A computer controlled target changer makes it capable of analyzing 32 targets automatically. The sample target is rotated during irradiation, so that the average sample position is defined to 0.2 mm. Several sets of 5 to 9 calibration targets have exhibited a standard deviation of less than 1%.
High Speed Image Converter X-Ray Studies
Authors: Chamelton V. , Clément G. , Roux J. P. , Gex J. P.
Published: March 2019

Important data in the investigation of laser-produced plasmas will be provided by studies of the X-ray emission characteristics in the range 1-10 keV, with time resolution comparable to plasma heating times. Present techniques using conventional photomultipliers or photodiodes are not suitable for time measurements on plasma heated by short optical pulses of several hundred picoseconds or less. The development of new X-ray cameras is also necessary. Their photocathodes must be chosen with care. In this paper we describe an initial study of the characteristics of metallic photocathodes: quantum efficiency, energy distribution of emitted photoelectrons, etc. Then we worked out the provisional sensitivity, spatial and temporal resolution of cameras in the streak mode or in shutter mode.
Direct X-Ray Response of Self-Scanning Photodiode Arrays
Authors: Koppel Louis N.
Published: March 2019

Self-scanning photodiode arrays were tested for their ability to measure the spatial distribution of low-energy x rays in a wavelength dispersive spectrometer. X-ray spectral sensitivity was measured with a calibrated de source of nearly-monochromatic characteristic-x rays with photon energies in the range of 1.5 to 8 keV. Photodiode response was found to be linear with x-ray flux. Exposure to large doses of copper radiation did not effect sensitivity. A mathematical model that describes the experimental data is presented. We found that spatial resolving power was lowered by the dispersal of photogenerated charges. This effect was investigated with collimated beams and is described with a formula that predicts the loss of diode signals.
Valence Band Spectroscopy in the Ultrasoft X-Ray Region (50 to 100 A)
Authors: Henke Burton L. , Taniguchi Kazuo
Published: March 2019

Transitions from the valence electron levels into the first relatively sharp inner sub-shell levels result in characteristic x-ray emissions in the 100-200 eV region. These spectra sensitively reflect the chemical state of the atoms which are representative of the submicron thickness of the sample surface under low energy x-ray excitation and of the first few molecular layers of the sample under electron excitation.

An optimized measurement method for this 50-100 A spectral region is “based upon single crystal spectrometry using a lead stearate analyzer which has high dispersion and efficiency and an energy width of about one eV in this wavelength range. Spectra are recorded using “tuned” proportional counter detection. In the work reported here, low energy x-ray excitation is used in order to minimize the possibility of radiation damage of the sample.

Each spectrum is calibrated for both energy and instrument transmission using known, sharp M lines of elements such as molybdenum, zirconium and yttrium which will bracket the spectraj. range under measurement. A simple method has been developed for "stripping" from the measured spectra the Lorentzian crystal width and the Gaussian collimation width in order to allow an estimation to be made of the actual emission line widths as well as the relative intensities.

In this report, as an illustrative application example, S-LII, III spectra are presented for a series of sulfur compounds in "both solid, and gas states. Manne's approximate molecular orbital interpretation of the x-ray emission spectra has been adopted and extended to apply to the LII, III spectra for second row elements.
X-Ray Analytical Methods for Evaluating Levels of Environmental Particulates
Authors: Leroux J. , Davey A.B.C. , Reid W.W. , Chalifoux Chantal
Published: March 2019

An exact knowledge of environmental particulate levels at their sources of production, geographic sites of dissemination and/or anatomic sites of deposition after they have been inhaled or ingested by the body is considered a main priority in the environmental health field. One must therefore recognize the need for rapid, accurate and sensitive means of sampling and analyzing these materials, often found in trace amounts, with little alteration from their original physical and chemical structure. A summary of the various theoretical approaches and methodologies investigated in our laboratory towards that goal are discussed with emphasis on X-ray techniques used, correction factors involved, and areas requiring further research.
Peak Height Approximation for X-Ray Diffracted Integrated Intensity
Authors: Gazzara C. P.
Published: March 2019

A fast X-ray diffraction powder method of quantitative analysis has been developed and demonstrated using mixtures of alpha and beta silicon nitride and silicon.

An analytical procedure, assuming both Gaussian and Cauchy diffracted characteristic line distributions, was used to synthesize CuKα X-ray peaks in the 2θ range 20° to 50° with peak widths from 0.1° to 0.4° 2θ. The relationship of peak height to integrated intensity was established as a function of peak width and tested using pure silicon powder with variable receiving slit widths from 0.01° to 0.40° 2θ.

Concentration calibration curves for silicon nitride and silicon were corrected for extinction and preferred orientation with statistical figures of merit to indicate the extent of preferred orientation.

Preliminary results indicate that this procedure may be used for cold-worked materials.
Conversion of Monetite, CaHPO4, To Apatites: Effect of Carbonate on the Crystallinity and the Morphology of the Apatite Crystallites
Authors: LeGeros Racquel Z. , LeGeros John P. , Trautz Otto R. , Paul Shirra W.
Published: March 2019

The incorporation of carbonate in the apatite causes a decrease in crystallite size as demonstrated in precipitated apatites prepared at 37°C. Carbonate disturbs the crystallization of the growing apatite crystallites to such an extent that materials with more than 15 wt% CO3 gives an ‘amorphous’ x-ray diffraction pattern. The incorporation of carbonate in precipitates prepared at 100°C. causes a shortening of the a-axis and a lengthening of the c-axis which is proportional to the carbonate content, supporting the concept that in these apatites, CO3 substitutes for PO4 (11). X-ray diffraction linebroadening studies of CO3-apatites precipitated at 100°C and electron micrographs show that the size and shape of the crystallites change from long needles to smaller rods to tiny spheroids, depending upon the amount of CO3. Carbonate causes the bonding in the apatite to become weaker and more isotropic, which results in the small spheroidal crystals.

This paper reports the effect of carbonate on lattice parameters and morphology of carbonate-apatites which have been prepared by the conversion of rnonetite, CaHPO4 in hot carbonate solutions. The structural effects of CO3 on the apatite is further reflected by the modification of the vibrations of the PO4 groups in the infrared absorption spectra. The morphology of ‘amorphous’ CO3- containing apatitic precipitates and that of CO3∼apatite with high CO3 content (prepared at 100°C) is similar, i.e., spheroidal in shape, but greatly differing in crystallite size.
A Standard Reference Material Containing Nominally Four Percent Austenite
Authors: Hicho G.E. , Yakowitz H. , Rasberry S.D. , Michaelis R.E.
Published: March 2019

This standard was produced by powder metallurgical techniques using known amounts of austenite. Using these techniques, 134 specimens were prepared. Because these standards are expected to be used primarily for the calibration of X-ray diffraction equipment, only one surface of each standard is certified, and these surfaces range from 3.1 percent to 5.2 percent in austenite content. To make the specimens, 310 stainless steel powder (austenitid) was blended with 430 stainless steel powder (ferritic) to make a mixture of 5 percent austenite in ferrite. The material was compacted, sintered, polished and etched so the austenite appears white and the ferrite, a deep brown. Then quantitative microscopy methods were used to determine the percentage of austenite near the surface. Furthers more, the 310 powder contains 20 percent of nickel while the 430 powder contains virtually no nickel. Therefore, after establishing a meaningful calibration curve, X-ray fluorescence analysis for the nickel content was also used as a direct measurement of the amount of retained austenite on the surface of the compact. Both procedures were carried out on fifteen specimens statistically selected from the total number of compacts produced. Agreement, within experimental error limits, was obtained between the X-ray fluorescence results and quantitative microscopy results. The X-ray fluorescence method was used to characterize all additional compacts. X-ray diffraction determinations of austenite content are in good agreement with the X-ray fluorescence and quantitative microscopy results. The compacts may be used as X-ray diffraction standards for austenite or in special cases as X-ray fluorescence standards for nickel content.
Solid Solution Decomposition of Aluminum-Rich Aluminum-Zinc-Silver Alloys
Authors: Bates S. R. , Gould R. W.
Published: March 2019

Solid solution decomposition of several aluminumrich aluminum-zinc-silver alloys were investigated using x-ray small angle scattering, x-ray diffraction (Guinier and Dewolff camera) and transmission electron microscopy. A decomposition sequence was observed directly fay means of hot stage electron microscopy, to be:

G. P. zone → ɛ' → ɛ

G.P. zones were observed to exist in all of the ternary Al-Zn-Ag alloys used in this investigation. Only one type of G.P. zone was detected and evidence is given which indicated that the G.P. zone formation was governed by the existence of a metastable miscibility gap. Experimental results also indicated that the lattice of the matrix is distorted by the presence of the G.P. zone.

A transition phase, designated ɛ', was observed to nucleate on defects in the matrix and to have a hexagonal close-packed structure. The ɛ' phase is partially coherent and much more regular in spatial distribution than the equilibrium ɛ phase.
X-Ray Production Efficiencies for K-, L-, M-, and N-Shell Excitation by Ion Impact
Authors: Needham P. B. , Sartwell B. D.
Published: March 2019

A systematic study of the production of characteristic X-rays by both light and heavy charged particles has been made. Using protons in the energy range 70-200 keV, data have been obtained for twenty-one X-ray lines encompassing a wavelength region from 1.44 to 44.00 Å from K-, L-, M-, and N-shells of elements with 6 ≤ Z ≤ 92. Additional X-ray production efficiencies have been measured in the K-, L-, M-, and N-shells using incident H2+, He++, N++, O++, and Ar++ ions in the energy range 90-400 keV. The ion beams were obtained from a 300 kV electrostatic accelerator, and beam analysis was obtained using a 7 kilogauss analysing magnet.

The data for proton excitation show that, for X-rays of a given wavelength, the X-ray production efficiency increases with the principal quantum number of the atomic shell being excited. These results contradict results reported by Sterk et al, but agree with results obtained earlier by Khan et al.

The results also show that the use of heavy ions (z > 5; obtains X-ray yields which are orders of magnitude higher than a repredicted by the direct scattering theory as used for protons and alpha particles.

Ion excitation of X-rays has been applied to the study of the oxidation kinetics of iron as part of a surface physics program. The wide range of target penetration depth as a function of both mass and energy of the ion has allowed us to study oxide film thickness as a function of oxidation temperature and impurity depth and concentration. Data are presented for protons and argon ions incident on high- purity ion with surface oxide films varying in thickness from 35 Å to 750 Å. Oxygen and carbon sensitivities to equivalents of fractional monolayers are routinely obtained using nondispersive analysis of the X-rays.
Particle Statistics and Whole-Pattern Methods in Quantitative X-Ray Powder Diffraction Analysis
Authors: Smith Deane K.
Published: March 2019

Modern powder diffraction employing computer-controlled diffractometers now allows quantitative analytical methods to use the whole diffraction trace rather then only individual peaks. Two such methods are in common use the Rietveld method which refines the crystal structures of the component phases as part of the matching calculation, and the patternfitting method which uses reference patterns from a database. Potential accuracies of these methods seems to be around 1 % absolute. The most severe limitation on the potential accuracy of these methods is particle statistics, which has been reviewed in considerable detail.
Grazing-incidence X-Ray Analysis of Surfaces and Thin Films
Authors: Huang T. C.
Published: March 2019

Grazing-incidence X-ray analysis techniques which are commonly used for the nondestructive characterization of surfaces and thin films are reviewed. The X-ray reflectivity technicue is used to study surface uniformity and oxidation, layer thickness and density, interface roughness and diffusion, etc. The grazing-incidence in-plane diffraction technique is used to determine in-plane crystallography of epitaxial films. The grazing-incidence asymmetric-Bragg diffraction is used for surface phase identification and structural depth profiling determination of polycrystalline films. Typical examples to illustrate the types of information that can be obtained by the techniques are presented.
Powder X-Ray Diffraction Characterization of Laser Deposited Ferroelectric Thin Films
Authors: Wong-Ng W. , Huang T.C. , Cook L.P. , Schenck P.K. , Vaudin M.D. , Chiang C.K. , Robins L.H. , Brody P.S.
Published: March 2019

Thin films of BaTiO3and Pb(Zr53Ti47)O3(PZT) have been deposited on Pt and Pt-coated silicon substrates using both Nd-YAG and excimer lasers. The BaTiO3films were prepared using heated substrates and were crystalline. The PZT films were deposited at room temperature and were amorphous; on annealing, they crystallized and gave rise to well-defined powder x-ray diffraction patterns.

To compare and correlate the properties and processing conditions of these thin films, characterizations were performed using a variety of analytical techniques including x-ray diffraction, TEM, SEM/EDX and ferroelectric and dielectric property measurements. The x-ray diffraction technique was used for identifying the various phases formed and also for analyzing the profiles of the diffraction peaks. Both the PZT films annealed below 800°C and the BaTiO3 films typically show polycrystalline x-ray diffraction patterns corresponding to a pseudo-cubic structure (i.e no peak splitting) instead of the tetragonal patterns characteristic of the target materials. It was found that for the BaTiO3films the pseudosymmetry was due to crystallographic alignment of the longer c-axis In the substrate surface to relieve strain. In the FZT films annealed below 900°C, it is suggested that the residual surface strain and/or small crystallite size of these materials may have precluded the peak splitting; at higher annealing temperatures, the tetragonal symmetry was recovered.
Characterization of Perovskite-Like Substrates for Thin Film Superconductors using Synchrotron X-Ray Topography
Authors: Yao G.-D. , Hon S.Y. , Dudley M. , Phillips Julia M.
Published: March 2019

The characterization of defect configurations in various perovskite-like substrate materials for high Tc superconductor epitaxial films has been conducted using white beam synchrotron X-ray topography. The substrates were found to contain crystal lattice defects such as twins, dislocations and grain boundaries. It is shown that characterization of substrates can potentially afford insight into factors controlling the properties of the high Tc superconductor tilms supported on them. This can help in the selection of optimum substrate material. Defect formation mechanisms in individual materials as well as their respective influences on the films are discussed. Comparisons between the physical and chemical properties of several potential substrate materials are presented.
Preferred Orientation Analysis in Textured Materials
Authors: Bunge H.J.
Published: March 2019

Polycrystalline materials may either be compact such as metals, ceramics, or some polymers or they may be powder samples. In both cases preferred orientation of the crystallites must be taken into account. In compact materials, texture formation by solid state processes and the texture-property relationship are the main purposes for texture investigations. In powder diffraction, texture correction can increase the accuracy of the results. Also strongly textured samples may be used in order to seperate diffraction peaks which are coincident in random powders.
Texture Characterisation in X-Ray Powder Diffraction using the March Formula
Authors: O'Connor B.H. , Li D.Y. , Sitepu H.
Published: March 2019

Texture, i.e. preferred orientation (PO), of crystallites can cause serious systematic errors in quantitative analysis of crystalline materials using x-ray powder diffraction (XRPD) data. The singleparameter model of March (1932), proposed by Dollase (1986) for use in powder diffractometry is a promising mathematical formalism for correcting PO in XRPD analysis of uniaxially-oriented specimens. O'Connor et al. (1991) successfully applied the March formula in applying preferred orientation corrections for gibbsites, Al(OH)3, using Rietveld pattern-fitting and a line ratio method in which corrections are determined according to the intensity ratios of selected lines. The paper gives an appraisal of the general applicability of the methods considered by Li and O'Connor with particular reference to powder diffraction data for gibbsite, molybdite (MoO3), calcite (CaCO3) and kaolinite specimens. It is shown that some caution should be exercised when using the March formula to describe PO in Rietveld analysis.
Texture Development in Powder Mixtures
Authors: Gao B. , Bunge B. J. , Fantner C. J. , van der Veen R. A.
Published: March 2019

The development of preferred orientation, by powder compaction was studied in several single phase, two-phase and three-phase powders. It was found that texture formation depends strongly on the properties of the powder particles and the preparation technique. In powder mixtures strong interaction effects were observed which either enhanced or reduced the degree of the preferred orientation. The required degree of series expansion of the texture function ranged from zero up to about fourteen.
Opportunities for Materials Analysis with Next Generation Synchrotron Sources
Authors: Hart Michael
Published: March 2019

Polycrystalline and powder diffraction is the most commonly practised method of x-ray analysis. During the last decade the construction of dedicated synchrotron radiation sources has resulted in the renaissance of these x-ray analysis methods; ab initio structure analysis and refinement, quantitative analysis of the structure, composition and stress in thin films and on surfaces, have all been improved. New techniques providing extremely high resolution, using anomalous dispersion, diffraction and scattering at grazing incidence to control x-ray penetration depth, have been developed. This brief review of work with W. Parrish at Stanford Synchrotron Radiation Laboratory and R. J. Cernik at the Daresbury Synchrotron Radiation Source is extended to indicate how third generation sources might be exploited in materials science.
2θ/α Scan X-Ray Powder Diffractometer
Authors: Kobayashi Yuji
Published: March 2019

The Bragg-Brentano focussing method (2θ/θ scan) is widely used in X-ray powder diffractometers. We have recently manufactured a diffractometer (2θ/α scan) whose incidence and reflection sides are asymmetrical. This report describes the optical system, including evaluation and application. The present method enables the following benefits to be obtained by simply changing the sample-to-receiving slit distance b without changing the X-ray source-to-sample distance a: (1) enhanced angular resolution, (2) increased diffracted X-ray intensity, and (3) variable asymmetrical angle. The experimental results show that the focussing condition of this optical system was satisfied. It also shows that the intensity of diffracted X-rays could be increased by approximately 1.4 times at b = 100 mm when the intensity at a = 185 mm and b = 185 mm was assumed to be 1. Furthermore, it was verified that FWHM can be reduced by making sample to receiving slit distance greater.
Recent Developments in Stress Analysis by Diffraction Methods
Authors: Hauk V.
Published: March 2019

Starting in Germany (Garmisch Partenkirchen, 1986) we had the 1st ICRS (Int. Conf. on Residual Stresses). The second was held in France (Nancy, 1988), the third in Japan (Tokushima 1991). In all areas, the diffraction measurements furnish exceptional contributions, and in many cases they are the only methods capable of solving problems. Because of the importance of the diffraction methods, the literature on residualstress analysis (RSA) has enlarged in the last years, Figure 1.
A Comparison of X-Ray and Neutron Diffraction Measurement of Lattice Parameters for the Determination of Residual Stress and Chemical Composition in Zirconium Alloy Tubes
Authors: Griffiths M. , Winegar J.E. , Mecke J.F. , Holden T.M. , Holt R.A.
Published: March 2019

Intergranular residual stresses can exist in zirconium alloys, especially when there is a large distribution of grain orientations. The stresses result from the anisotropic plasticity and thermal expansion of the hexagonal close-packed crystal structure of α-zirconium. Apart from complicating the characterisation of materials using lattice parameter measurements, the intergranular stresses can significantly affect material behaviour, especially in nuclear reactor environments, and there is therefore a great deal of interest in their measurement.

The effects of specimen preparation and surface relaxation on X-ray diffraction measurements of lattice parameters of zirconium alloys have been investigated by comparing bulk neutron diffraction with X-ray diffraction on identical materials. The results show that: (i) intergranular or interphase residual stresses exist in dual-phase Zr-2.5Nb pressure tubes; (ii) the stresses normal to the surface of an X-ray diffraction specimen are not relieved completely when there are intergranular residual stresses in the material. One can conclude that intergranular stresses have to be considered when determining chemical compositions from lattice parameter measurements and also when measuring macroscopic residual stress using X-ray diffraction.
Profile Fitting by the Interference Function
Authors: Lutterotti Luca , Scardi Paolo
Published: March 2019

On the basis of the “column-like” powder model of Warren and Averbach, a profile fitting procedure was devised to obtain microstructural disorder parameters. The interference function

where d is the interplanar distance, λ the wavelength, θ the diffraction angle and N the number of cells within a column, was used to model experimental profiles taking into account the column-like crystallite size and r.m.s. strain distributions. The procedure can be applied both to single peak and to two or more peaks of multiple order of reflection. The method was tested on several samples, also having a bimodal size distribution, and the results compared with those obtained by the well-established Warren-Averbach analysis.
X-Ray Diffraction from a 28 Attoliter Crystal Volume
Authors: Skelton E.F. , Ayers J.D. , Qadri S.B. , Hu J.Z. , Finger L.W. , Mao H.K.
Published: March 2019

Metallic filaments with sub-micrometer diameters have recently been fabricated using novel materials fabrication techniques at NRL. The specimens are enshrouded in a glass sheath and all efforts to obtain structural information from these samples with conventional x-ray sources have been negative. By using synchrotron radiation on a wiggler beam line, x-ray diffraction data have been obtained from samples with diameters of 0.22, 0.09, 0.07, and 0.04 μm. The two thicker samples were found to be single crystals with a structure consistent with that of normal Bi. Single crystal diffraction peaks obtained from the 0.07 μm sample are incompatible with the Bi-1 or any other known structure of Bi. We have provisionally identified this as Bi-X.
Performance Characteristics of a High Resolution Si(Li) Detector Using a Time Variant Amplifier and a Pulsed Source of X-Rays
Authors: Short M. A. , Gleason T. G.
Published: March 2019

Two recent improvements in energy dispersive spectrometry are the development of time variant amplifiers and the introduction of pulsed X-ray sources. Either pulsed X-ray tubes or electron beams with fast beam blanking may be used.

Time variant amplifiers designed by Kandiah (1 ,2) used control logic to co-ordinate charge restoration of the detector preamplifier, pole-zero cancellation and baseline restoration. In the pulse shaping circuit, time constants are switched during the processing of each pulse to optimize throughput, baseline stability and pileup rejection. Pulse processing techniques have been discussed by Statham (3) .
The Use of Polarized X-Rays for Improved Detection Limits in Energy Dispersive X-Ray Spectrometry.
Authors: Ryon Richard W. , Zahrt John D. , Wobrauschek Peter , Aiginger Hannes
Published: March 2019

The use of polarized x-rays to excite fluorescence spectra with decreased backgrounds and improved detection limits is reaching a mature state of development. With bulk, low-Z specimens, polarized x-ray sources have produced detection limits which are ~℩ to 3 times lower than are obtained with the best unpolarized photon sources. Based upon experience and the known properties of larger solid angle geometries, further significant to dramatic improvements are anticipated.
A Modular ADC/Microcomputer System for Energy Dispersive X-Ray Spectroscopy
Authors: Hale D. , Satterfield T. , Blankenship D. , Russ J. C.
Published: March 2019

Multichannel analyzers, as used in energy dispersive X-ray spectrometers using Si (Li), High Purity Ge, or other types of detectors, receive a series of pulses, generally in the 5 to 10 volt range full scale, which they measure and count in memory. Some are constructed using hardwired digital logic circuits to perform these memory control operations, while others incorporate standard computer memories and central processing units, with programmed logic for storing, displaying and (generally) processing the spectrum, with the advent of ever more powerful and lower cost microcomputers, it becomes increasingly attractive to adapt one to this purpose. We have done so, using an Apple II, and will describe the hardware of the interface, the logic of the data acquisition programs, and the utilization of memory in the computer.
Feasibility Study for On-Stream X-Ray Analysis of Barite
Authors: Gurvich Yury M.
Published: March 2019

Modern on-stream X-ray equipment for slurry analysis is now used in hundreds of mines throughout the world. This technique provides valuable information for process control which cannot be achieved by other analytical methods. One of the most recent successful examples is the Brenda Mines, in Canada, where the ARL Process Control X-ray Quantometer (PCXQ) is used for ten different streams in a Cu-Mo concentrator.

The success of slurry analysis is highly dependent upon the analytical method selected, based on the following factors: (i) the features of the analyzed materials, (ii) the concentration ranges, (iii) percent of solids, and (iv) requirements of analytical accuracy and precision. A preliminary investigation of methods and of analytical conditions can be done on a laboratory X-ray spectrometer using solid models of slurry. Such preliminary work significantly simplifies the introduction of the new technology and helps in the preparation of proper specifications.
Energy Dispersive X-Ray Measurements for Cesium and Silver in Zeolite Ion-Exchange Columns
Authors: Vincent H. A. , Patton M. E.
Published: March 2019

Distribution of cesium and silver ion-exchanged onto columns of zeolites may be measured directly and non-destructively on the column with the use of radioisotope-excited energy dispersive X-ray fluorescence. Quantitative accounting of the exchanged metals is obtained without elution.
The Application of X-Ray Fluorescence and Diffraction to the Characterization of Environmental Assessment Samples
Authors: Censullo Albert C. , Briden Frank E.
Published: March 2019

The Technical Support Staff is called upon for analysis of a wide variety of sample types many of which have little sample history. However, it is usually necessary to account for all elements present. For these reasons, x-ray fluorescence spectrometry (XRF) has been a useful tool. Unfortunately, XRF requires the use of a range of standards for each element, the preparation of which could become so time consuming that the advantages of XRF would soon be diluted. Consequently, the utility of the J. W. Criss fundamental parameters computer program was evaluated for samples in which only one standard per element was used and where the standard matrix did not strictly resemble the unknown matrix. Some of the results of these tests on environmental assessment samples are reported here.
A Second Generation Automated Powder Diffractometer Control System
Authors: Snyder Robert L. , Hubbard Camden R. , Panagiotopoulos Nicolas C.
Published: March 2019

The real-time x-ray powder diffractometer control system AUTO incorporates several advances in data collection and analysis. Counting procedures for selected area data collection are optimized to achieve either a preselected statistical error in minimum time or a minimum error in fixed total time. Run files are employed to greatly simplify quantitative analysis procedures and for controlling repetitive runs. External calibration curves for 20 are used to eliminate all but sample dependent aberrations to peak positions. A generalized data file structure is used to document the instrumental variables and sample parameters.
Determination of Residual Stresses in Austenite and Martensite in Case-Hardened Steels by the sin2ψ Method
Authors: Kim Chongmin
Published: March 2019

Compressive residual stress is one of the essential elements which contributes to the exceptional fracture resistance of case-hardened components. The sign and magnitude of residual stress are determined by transformation characteristics, thermal and mechanical histories of the steel. Accurate determination of residual stresses is essential in research on case-hardened steels.
X-Ray Characteristics and Applications of Layered Synthetic Microstructures
Authors: Gilfrich J. V. , Nagel D. J. , Loter N. G. , Barbee T . W.
Published: March 2019

Practitioners of wavelength-dispersive x-ray spectroscopy are always seeking better dispersing devices. The wavelength-dispersive instrument is called a “crystal spectrometer” because natural or synthetically-grown crystals are most often used. Occasionally, other “manufactured” dispersers are suggested for specific applications: highly oriented polycrystalline graphite provides much higher intensities than the crystals usually used for the K-lines of P, S and Cl; Langmuir-Blodgett films (heavy metal salts of fatty acids) provide 2d-spacings over the range of 70 to 130 A, making soft x-ray spectroscopy practical in a wavelength range for which natural crystals are not available.
The Application of X-Ray Diffraction for Glass Batch Homogeneity Determination
Authors: Kim H. S. , Cohen C. I.
Published: March 2019

An X-ray diffraction (XRD) technique is employed to determine the presence or absence of crystalline phases in glass batch and to determine its homogeneity qualitatively and quantitatively.

Sample preparation problems are discussed, and promising techniques for sample preparation are presented. Qualitative batch homogeneity determination is accomplished by comparing the integrated intensity of a particular reflection of the reference sample to that of the unknown sample. Quantitative batch determination is accomplished by using the internal standard method. Three replicated data sets indicate that the standard deviation of kaolinite and colemanite are higher than those of quartz and calcite. However, the overall data from the quantitative analyses lie within an acceptable range of precision and accuracy.
Profile Fitting in Residual Stress Determination
Authors: Devine T. J. , Cohen J. B.
Published: March 2019

Of major importance in the determination of residual stress via diffraction is the accuracy of the measurement of the scattering angle (2 θp) of a Bragg peak. This determines the accuracy of the interplanar (d) spacing and hence the strain and stress. In the U.S., the most commonly accepted method of determining peak position is a parabolic fit near the top of a peak. (While a diffraction peak is not parabolic, this is a satisfactory function near the maximum.) The error in this procedure has been derived and tested, and it has been shown that a multipoint fit with a least 7 points is rapid and as precise or more precise than the centroid, the bisector of the half width, or cross correlation, except for sharp peaks in which case the centroid or cross correlation are slightly better. Thus a parabolic fit is generally useful and, since a least-squares fit to this function is readily carried out on modem micro-processors, automatical of a stress measurement is possible, including evaluation of errors.
Neutron Powder Diffraction at a Pulsed Neutron Source: A study of Resolution Effects
Authors: Faber J. , Hitterman R. L.
Published: March 2019

The General Purpose Powder Diffractometer (GPPD), a high resolution (∆d/d=0.002) time-of-flight instrument, exhibits a resolution function that is almost independent of d-spacing. Some of the special properties of time-of-flight scattering data obtained at a pulsed neutron source will be discussed. A method is described that transforms wavelength dependent data, obtained at a pulsed neutron source, so that standard structural least-squares analyses can be applied. Several criteria are given to show when these techniques are useful in time-of-flight data analysis.
Recognition and Treatment of Background Problems in Neutron Powder Diffraction Refinements
Authors: Baur W. H. , Fischer R. X.
Published: March 2019

Irregular backgrounds in time-of-flight neutron powder diffraction data and nonlinear backgrounds in angle dependent neutron powder diffraction data. were corrected by fitting fifth degree polynomials to those portions of the data most affected. The anomalous background intensities were in both cases due to non Bragg scattering. The polynomial fitting was carried out over a sufficiently widerange of the profile to avoid interfering with the Bragg peaks. The corrected data gave internally consistent results for the crystallographically nonequivalent (Si,Al) -0 (1) and(Si, Al) -0 (2) bond lengths in zeolite rho and compare favorably with previous refinements of this Zeolite in space group Im3m. Internal and external in consistencies of bond lengths are just as diagnostic of refinement difficulties as negative isotropic temperature factors or non positive definite an isotropic temperature factors are.
Lattice Thermal Expansion Effects in Pure and Doped Cordierite by Time-of-Flight Neutron Diffraction*
Authors: Predecki F. K. , Haas J. , Faber J. , Hitterman R. L.
Published: March 2019

The thermal expansion behavior of pure, Ge-doped and Li-doped hexagonal cordierites with respective compositions: 2MgO 2Al2O3 5Si02 2Mg0 2Al2O3 4Si02 Ge02) and 2MgO (2+x)AL203 (5-2x)Si02 xLi20 with x = .174, was investigated using time-of-flight neutron powder diffraction at temperatures from 22 to 750°C in vacuum. The data were refined in space group P6/mcc using the Rietveld method. The lattice thermal expansion curves of all 3 samples were quite similar. The negative axis expansion is associated with (1)displacement of the T2 cations generally toward the axis channels and (2) changes in the distortion of the coupled T1/M tetrahedra/octahedra in the structure. Both contributions were present in all 3 samples but the first was more dominant in the Ge doped sample. The nature and origin of the distortions in T1 and M are discussed.
Application of Quantitative X-Ray Diffraction Analytical Methods to the Study of High-Magnesium Phosphorites
Authors: Blanchard Frank N. , Goddard Robert E. , Saffer Barbara
Published: March 2019

Phosphorite is a sedimentary rock with a high enough content of phosphate minerals to bo of economic Interest. Most phosphorites are composed predominantly of m1crocrystall1no to cryptocrystalline carbonate fluorapatlte thenceforth In this report referred to simply by the mineral group name apatite). Florida produces roughly 1/3 of the world's supply of phosphate rock, most of which is used 1n the fe rtiliz e r Industry.

Long term continuation of phosphorite mining In Florida will require exploitation of the extensive hlgh-magneslum phosphorite deposits south of the present mining d istrict 1n central Florida, and this will require new technology In order to produce beneficlated concentrates with less than 1% MgO, a limit Imposed by fe r tiliz e r processing technology. In order to develop benefication methods applicable to these ores, it is essential to know how Mg occurs in phosphorites. Dolomite, CaMg(C03)2, is the chief host of Mg In phosphorites from Florida. Magnesium may also be present, however, as a substituent In apatite (the chief phosphate.mineral in these deposits), as a minor substituent 1n calcite (CaCO3), in certain clay minerals (particularly palygorskite and to a lesser extent in some smectites), and/or in organic matter within the apatite particles.
Instrumentation for Synchrotron X-Ray Powder Diffractometry
Authors: Parrish W. , Hart M. , Erickson C. G. , Masciocchi N. , Huang T. C.
Published: March 2019

The instrumentation developed for poly crystalline diffractometry using the storage ring at the Stanford Synchrotron Radiation Laboratory is described. A pair of automated vertical scan diffractometers was used for a Si (111) channel monochromator and the powder specimens. The parallel beam powder diffraction was defined by horizontal parallel slits which had several times higher intensity than a receiving slit at the same resolution. The patterns were obtained with 2:1 scanning with’ a selected monochromatic beam, and an energy dispersive diffraction method in which the monochromator is step-scanned, and the specimen and scintillation counter are fixed. Both methods use the same instrumentation.
Changes in the Unit Cell Dimensions of ZSM-5 Produced by the Adsorption of Organic Liquids*
Authors: Pollack S. S. , Gormley R.J. , Wetzel E. L.
Published: March 2019

The adsorption of liquids in 2eolites has been a widely studied phenomenon, and with the development of ZSM-5, considerable work has been carried out on this zeolite, However, few articles have been published dealing with changes in the X-ray diffraction patterns when the zeolite pores contain adsorbed molecules. The purpose of this paper is to report changes in the X-ray diffraction pattern of ZSM-5 after mixing it with various organic solvents.

This work began after studies of both deactivated and partially deactivated ZSM-5 catalysts showed that their X-ray diffraction patterns changed in intensities and peak positions after use in microreactor studies. If coke or hydrocarbons were causing the above changes, as postulated, would hydrocarbons adsorbed in ZSM-5 produce the same changes? Simpson and Steinfink showed that the low-angle lines of faujasite decreased in intensity after the adsorption of m-dichlorobenzene.
Single-Line Profile Analysis of Superplastically Deformed Aluminium Alloys
Authors: Bowen A. W.
Published: March 2019

Superplastic deformation involves the controlled processing of materials in order to produce extensive deformation, the longest recorded elongation being nearly 5000%. Components of very complex shape can be formed in this way, thus offering substantial savings over the use of conventional manufacturing routes. Typically, these savings can be 50% in cost (through reduced man-hours required for component manufacture, from improved structural efficiency and from reduced material costs) and 25% in weight (through more efficient use of materials and the reduced requirement for joints and fasteners).

The success of the superplastic process will depend, in large part, on achieving an adequate balance between the deformation input and the relief of work hardening by thermally activated relaxation processes. An attempt has therefore been made to establish whether the residual strain in superplastically deformed materials is related to deformation, parameters, and if so, to interpret this strain data in terms of the mechanisms of superplasticity.
X-Ray Double Crystal Diffractometry of Multiple and Very Thin Heteroepitaxial Layers
Authors: Tanner B. K. , Hill M. J.
Published: March 2019

The intense interest in production of heteroepitaxial quaternary structures of Gax In1-x Asy p1-y on InP for electro-optical telecommunications systems has Stimulated development of non-destructive techniques for their analysis. One of the most important is double axis X-ray diffractometry, a technique originally developed in the 1920s but only now coming into widespread use as a routine assessment tool. The basic theory is well treated by James and discussion of alignment errors are found in references cited by Fewster in a paper describing alignment procedures for the automated diffractometer manufactured by Bede Scientific Instruments of Durham, The application to III-V systems has been discussed by Tanner, Barnett and Bill.
Sampling and Data-Taking Strategies in X-Ray Fluorescence Assay of Low S/N Solutions
Authors: Hudgens Claude R.
Published: March 2019

This project was Initiated for the purpose of demonstrating the feasibility of on-line x-ray fluorescence (XRF) analysis for the nondestructive assay of fissile elements (SNM) in reactor fuel reprocessing (dlssolver) solutions, using wavelength dispersive x-ray fluorescence analysis because of its high immunity to the intense gamma emissions of the solutions. A prime objective of this project was the identification and dimensioning of.the parameters critical to XRF assays of high accuracy. The concepts presented herein, though directed primarily to assay of solutions with emphasis on low signal-to-noise conditions and low count rates, are applicable to all assays of solids, slurries, and gases.
Determination of Wear Metals in Oil by X-Ray Spectrometry
Authors: Liu Ya-Wen , Harding A.R. , Leyden D.E.
Published: March 2019

Trace elements in oil may be determined by adsorption of the oil sample onto maguesium oxide followed by thermal degradation of the organic material. The resulting powder is easily pressed into a pellet suitable for X-ray spectrometric analysis. The lower limit of detection depends upon the trace impurities in the MgO and is a few parts per million for most elements determined.
Highly Automated Techniques for On-Line Liquid Analysis With an XRF System
Authors: Miller R. A. , Kalnicky D.J. , Rizzo T. V.
Published: March 2019

Sophisticated matrix correction techniques have been successfully applied to analysis in an interactive laboratory environment (1-3). The present paper describes their application, to an on-line industrial environment, where reliable operation is to be maintained with a minimum of operator intervention. Out of bound situations must be detected and corrected automatically to the extent possible. Programming must be substituted for human judgement, within restricted circumstances.
Evaluation of a Mobile XRF Analyzer in an Industrial Laboratory
Authors: Johnson Norman F.
Published: March 2019

Traditionally x-ray spectrometers have been designed to analyze perfectly prepared specimens that are flat and highly polished such as 32mm discs. Certainly the best analytical results are obtained on such samples, however in an industrial laboratory it is also neccessary to obtain statistically valid results on samples that are less than ideal in size and geometry. The problem at the TRIDENT Refit Facility is to analyze large metal parts such as pump casings, valve bodys, flanges, and finished piping sections that are going into the repair of TRIDENT class submarines. Energy dispersive X-ray techniques have long been recognized as fast and non-destructive and are therefore ideally suited to the analysis of these finished metal parts.