bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photon Scattering from Single Crystals
Authors: Barrett Charles S. 
Published: March 2019

AbstractProtons and other energetic particles when back-scattered from a single crystal emerge with anisotropic Intensity distributions. There are minima In the intensities along crystallographic directions and planes. The indices of these directions and planes and the relative intensities of these crystallographic features can be readily established by photographing the pattern of emerging particles. The patterns disclose the symmetry of the scatterer but cannot be expected to reveal the presence or absence of a symmetry center, so that the symmetry of a pattern should be related to the symmetry of one of the 11 Laue-symmetry groups, Photographs made with 50-150 keV protons are found to differ not only for crystals that belong to different Laue groups, but also for crystals belonging to the same Laue group but having different space lattices. The patterns reveal a limited amount of structural information including information on orientation, crystal perfection, and axial ratios, but not unit cell dimensions, The interpretation of patterns on the basis of particle trajectories has had major successes in the past; interpretation on the basis of diffraction has also been proposed but the inherent complexities associated, with this are very severe. Some intensity relationships observed for various crystals a-re presented, and highly simplified approximate ways of predicting relative intensities of lines are compared with the observations.
Determination of Particle Size Distribution in a Dispersion Hardened Nickel Alloy Using Small Angle X-Ray Scattering
Authors: Gould R. W. , Bates S. R. 
Published: March 2019

AbstractIt has been recently shown that particle size distributions can be determined from small angle x-ray scattering data. Size distributions have previously been measured in aluminum-zinc and aluminum-silver alloys containing spherical Guinier-Preston zones. Inorder to obtain the size distribution it is only necessary to calculate the Guinier radius and the Porod radius.Dispersion hardened nickel alloys containing small spherical particles of thoria appear to be amenable to this type of analysis. A nickel-20% chromium-2% ThO2 alloy was selected for this study. The particle size distribution obtained by small angle x-ray scattering is compared with the transmission electron microscopy results found in the literature.
Kossel Line Micro-Diffraction Stum on Precipitation of Alpha from Beta in Copper Zinc Alloys
Authors: Shiwoda Gunji , Isokawa Kenji , Umeno Masataka 
Published: March 2019

AbstractBy the electron microprobe Kossel technique, an a-precipitate at a grain boundary of a Cu-45wt% Zn alloy was found to consist of only one crystal and the orientation relationship between the a precipitate and one of the grains beside the grain boundary was (110)β//(111)α and <111>β//<110>α. This is the same relationship as the case α a precipitates in β-phase grains. A little deviation from the exact coincidence of above orientation relationship was observed. The vacancy model for the production of a denuded zone in the same alloy was confirmed by a line scanning analyses using an electron microprobe. An effect or orientation differences was observed on the specimen current of the electron microprobe. This effect was attributed to a channelling phenomenon. The influence of ths channelling effect on quantitative analyses by electron microprobe was considered for the precipitated a-phase and matrix β-phase, and the massive a precipitates were found to consist of many crystallites having different orientations. From the lattice constant of the g-phase determined by the Kossel patterns, the concentration of zinc at the target point was obtained in good agreement with the value obtained by quantitative analyses using an electron microprobe. Thus, in some cases, the Kossel technique can be utilized for the quantitative analysis of a small portion without any corrections which are necessary In the case of electron microprobe.
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

AbstractDistinct 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

AbstractA 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

AbstractResearch 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

AbstractX-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.
In Situ Rock Analysis
Authors: Lantos J. , Litchinsky D. 
Published: March 2019

AbstractRecent 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.
The Fast Analysis of Uranium Ore by EDXRF
Authors: Vane Ronald A. , Stewart William D. , Barker Mike 
Published: March 2019

AbstractEnergy 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.
Monte Carlo Simulation of Sample Scattering Effects from Homogeneous Samples Excited by Monoenergetic Photons
Authors: Doster J. M. , Gardner R. P. 
Published: March 2019

AbstractThe 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

AbstractOne 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

AbstractA 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

AbstractPrimary 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.
Nanosecond Time Resolved X-Ray Diagnostics of Relativistic Electron Beam Initiated Events*
Authors: Kuswa Glenn W. , Chang James 
Published: March 2019

AbstractThe 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

AbstractThe 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

AbstractMeasurements 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

AbstractAn 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

AbstractThe 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.
Porotectosilicate Structure Determination from Model Building
Authors: Kokotailo George T. , Schlenker John L. 
Published: March 2019

AbstractPorotectosilicates 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.
The Use and Accuracy of Continuously Scanning Position-Sensitive Detector Data in X-Ray Powder Diffraction
Authors: Göbel Herbert E. 
Published: March 2019

AbstractBy 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.
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

AbstractA 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.
Energy-Dispersive Diffraction Analysis of the Structure of Metallic Glasses
Authors: Wagner C.N.J. , Lee D. , Tai S. , Keller L. 
Published: March 2019

AbstractThe 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.