bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Application of X-Ray Fluorescence Probe Analysis to the Study of Segregation in Steels
Authors: Johnson M. P. , Beeley P. R. , Nutting J. 
Published: March 2019

AbstractChemical analysis by the X-ray fluorescence microprobe technique offers potential means for the determination of compositional differences arising from the segregation of elements during the solidification of metals. The dimensional scale of the probe is expected to be suitable for the study of macro segregation and, in coarse-grained cast materials, of interdendritic micro segregation.This paper describes preliminary work carried out to establish analytical sensitivity in respect of some minor constituents present in homogeneous steel samples of known composition. The significance of the results is discussed in relation to the problems of segregation in steel, and it is concluded that the Siemens Kristalloflex IV equipment needs to be adapted for fully focusing operation to achieve the sensitivity required for this work. Details are given of the work so far undertaken in this direction.
Analysis of the Broadening of Powder Pattern Peaks using Variance, Integral Breadth, and Fourier Coefficients of the Line Profile
Authors: Halder N. C. , Wagner C. N. J. 
Published: March 2019

AbstractThe broadening of powder pattern peaks has been studied by three methods—Fourier analysis, integral breadth measurements, and variance of the line profiles. The results obtained from the variances are compared with those obtained from the integral breadths and Fourier coefficients.Tungsten filings were prepared at room temperature and their powder pattern peaks were recorded with a Norelco diffractometer using filtered Cu Kα radiation. The variances, integral breadths, and Fourier coefficients were calculated with the IBM 7094 computer. The results indicate that the variance is very sensitive to the range of integration s2 − s1 = (2θ2 − 2θ1) cos θ0/λ. An error of ± 10% in this range due to the difficulty in choosing the correct background changes the values of the variance significantly and the integral breadth to a lesser extent. However, the same error does not affect the values of the Fourier coefficients.Comparing the particle sizes and strains obtained by the three methods, it was found that the strains agreed remarkably well. The particle size calculated from the variance was smaller (DeW = 150Å) than that evaluated from the initial slope of the Fourier coefficients (De – 210Å) and from the integral breadths 2De ≃ D1 = 430Å.
Absorption Correction Curves Obtained from Measurements of the Production of X-Rays as a Function of Depth
Authors: Brown J.D. , Parobek L. 
Published: March 2019

AbstractMeasurements of x-ray production as a function of depth in a sample (ϕ(ρz) curves) are fundamental to the determination of the quantitative equations for relating x-ray intensity to composition in electron probe microanalysis. These ϕ(ρz) curves have been measured for four different voltages and a number of different tracers in aluminum, copper, silver arid gold as matrix elements. From these ϕ(ρz) curves the absorption correction curves (f(x) curves) can be calculated. Such curves have been obtained and comparison is made with the absorption correction equations of Philibert. The effect of a tilted sample on the absorption correction is also discussed.
Submicrosecond X-Ray Diffraction Studies
Authors: Mitchell A. C. , Johnson Quintin , Evans L. 
Published: March 2019

AbstractAs a result of interest stemming from shock wave studies carried out at Lawrence Livermore Laboratory, we have developed a capability to conduct x-ray diffraction studies in submicrosecond time intervals. This involves the use of a low impedance flash x-ray device. While there are many applications to which these techniques can be put, our first experiments deal with samples undergoing shock wave compression. These particular experiments are conducted by synchronizing a 40 to 50 nsec flash x-ray device to a shock front which is produced by the detonation of a high explosive placed in contact with a sample. Diffracted radiation is usually recorded on very sensitive film protected by a blast cassette. Thus far we have subjected lithium fluoride, aluminum, and carbon to pressures in the range of 100 to 300 kbar. Either powder or single crystal samples can be used. The principal difficulties of this experiment are the lack of sufficient intensity and the synchronization of the x-ray pulse to the shock front.
The Analysis of Berg-Barrett Skew Reflections and their Applications in the Observation of Process-Induced Imperfections in (111) Silicon Wafers
Authors: Juleff E. M. , Lapierre A. G. , Wolfson R. G. 
Published: March 2019

AbstractThe geometry of Berg-Barrett skew reflections (the normal to the specimen surface and the incident and reflected beam vectors are not coplanar) is analyzed with particular reference to (111) silicon. Angular relationships required for obtaining the 78 most intense such reflections are presented on stereographic projections. Skew reflections are utilized to adapt the Berg-Barrett technique of extinction-contrast micrography to the examination of the (111) wafers generally used in integrated circuit technology. Skew reflections are shown to be more suitable for Berg-Barrett micrography than the zero-layer reflections described by Newkirk; in particular, their versatility in providing a means of varying the angle of incidence of the X-ray beam for a specific reflecting plane is demonstrated. A relatively simple experimental arrangement is described for recording skew reflection images. It permits a high resolution X-ray sensitive plate to be placed parallel to the specimen, and their separation to be increased to as much as 5 mm without excessive loss of resolution ; this avoids both image distortion and surface scattering. Furthermore, the specimen area recorded in a single micrograph is 1-3 cm2, which is large enough to eliminate the need for scanning. Exposure times are very short, in the order of 10 min. Micrographs of boron-diffused silicon are presented showing device components delineated by solute strain, strain fields induced in epitaxial silicon films by underlying buried-layer diffusions, and diffusion-induced Lomer-Cottrell dislocations. These micrographs demonstrate the resolution and contrast obtainable over large specimen areas. The capability of the Berg-Barrett technique is discussed in the examination of the near-surface regions directly involved in device fabrication and operation.
Quantitative Microprobe Analysis by Means of Target Current Measurements*
Authors: Colby J. W. , Wise W. N. , Conley D. K. 
Published: March 2019

AbstractIn the microprobe analyzer, a portion of the high energy electrons impinging on the surface are backscattered from the sample and re-emitted at high energy levels. Low energy (less than 50 eV) or secondary electrons also ate emitted. Both the electron backscatter yield and the secondary electron yield are related to the mean atomic number of the target material and, hence, may be used to provide information about the target composition. Unfortunately, however, the secondary electron yield is very sensitive to the surface condition of the specimen and various instrument parameters. This complicates the otherwise simple linear relationship between sample composition and electron backscatter yield.It is shown that the effects due to secondary electrons can be minimized by biasing the sample, and that good results can be obtained in the analysis of binary systems. The limitations and utility of the method are discussed, and backscatter yields are determined.
A Method of Liquid Analyses Providing Increased Sensitivity for Light Elements
Authors: Beard D. W. , Proctor E. M. 
Published: March 2019

AbstractA method for analyzing solutions using a sample surface directly exposed to the primary X-ray beam is discussed. This method eliminates the need for the conventional Mylar covered liquid cells. The advantages of this method are the elimination of the scattering of the longer wavelength X-rays and the absorption effects due to the Mylar covering, thereby giving significant improvement in peak-to-background ratios and peak intensities for the light elements. This increased sensitivity can be used to improve the limits of detectability for light elements in solutions, broaden the range of practical elemental determinations, and reduce the counting time for any light element analysis in liquids.A new liquid cell, developed for this technique, provides easily repeatable setting of target-to-sample distance and simplified preparation and handling of samples. A comparison between results obtained with conventional method and this uncovered sample surface method is made for typical solution applications.
Theoretical Correction for Coexistent Elements in Fluorescent X-Ray Analysis of Alloy Steel
Authors: Shiraiwa Toshio , Fujino Nobukatsu 
Published: March 2019

AbstractWith fluorescent X-ray analysis as routine work, the correction term for the coexistent element can be expressed as linear terms of the weight fraction of the element because the compositions of samples are limited to a small range. Usually those correction factors which require a great deal of work are obtained experimentally. The authors have obtained theoretical equations of fluorescent X-ray intensity which are in good agreement with experimental values. The linear correction factors are obtained from derivatives of those equations, and their values can be easily calculated with a computer. The experimental X-ray intensity versus the weight fractions is usually expressed as a line. However, the linear approximation is not correct over a wide range of the composition. The second derivative of the theoretical equation explains the deviation from the linear approximation and gives the range where the linear approximation is allowed. The calculations are applied to the analysis of stainless steels, several low-alloy steels, and iron ores, and experimental results are corrected by the calculated results. Correction factors for Ni Kα, Fe Kα, Cr Kα, Mn Kα, and Cu Kα in stainless steels and Cr Kα and Mn Kα in low-alloy steels are calculated for coexistent elements such as carbon, silicon, titanium, chromium, manganese, copper, niobium, and molybdenum. For example, standard deviations of chromium and manganese analyzed results in lowalloy steels decrease from 0.169 and 0.044% to0.030 and0.023%, respectively, with theoretical corrections. In the analysis of iron ore, the fluorescent X-ray intensity of iron is affected by combined oxygen, which is different for the various compounds of iron oxides, and other impurities such as alumina, silica, and lime. The correction factors of these are obtained by calculation, and the standard deviation decreases from 1.70 to 0.44% for 55.1 to 68.5% iron. It is found by experiment that the theoretical values have about 1 or 2% of relative errors, and their derivatives also have relative errors of the same order of magnitude. But the ranges of coexistent elements are usually small, a few percent at most in routine work, and the theoretical values can be used in practical analyses.
Investigation and Demonstration of Single-Crystal and Powder Diffraction by using Zero-Power Beta-Excited X-Ray and 55Fe Isotopic Sources*
Authors: Preuss Luther E. , Toothacker William S. , Bugenis Claudius K. 
Published: March 2019

AbstractDemonstrable diffraction (powder or single-cry still) with the use of zero-power isotopic sources would provide important data on such systems and may have implications in analysis (in this work, we fabricated 100-mCi 55Fe, acceleratorproduced, and 4-mCi 117Pm-Cu beta-excited sources). Powder-diffraction efficiency with the use of a special diffrac to meter adapted to these sources is about 10−5 (calculated) for the Mn Kα X-rays (55Fe) on the NaCl 200 plane. This beam flux at three times natural background intensity was experimentally achieved by using photon spectrometry with proportional counters and multichannel analysis. The Lip diffraction pattern was demonstrated with intensities roughly in agreement with prediction. Lithium fluoride single-crystal diffraction intensity (200 plane) exceeded by 250-fold that of powder. Powder main-peak intensity (θ = 31.5°) produced 9.2 photons per minute at the receiving slit versus 2.3 × 103 events for the single crystal. This single-crystal intensity with 60-sec runs provided a peak resolution of 0.29° full width at half maximum. The first-order Kα, Kβ1 first order, and Kβ1 second-order beams (θ = 31.5°, 28.3°, and 71.6°, respectively) were demonstrated, with 1900 events per minute in the main peak (Kα). X-ray noscreen emulsion was used to study photographic recording on the LiF single crystal with exposures as short as 2.5 hr. A 2-in.-diameter camera, newly designed for the 55Fe source, is collecting further emulsion data.The isotopic source is stable, highly predictable in intensity, reliable, and compact. Requiring zero power, it thus has a potential for remote applications. Where its low output can be tolerated, it may hold promise for analysis, especially where its size, weight, and stability tire important criteria. Source work here points to possible 55Fe improvement in photon output of 102 over the source described here. Such an increase may make certain special analytical applications feasible.
Resin-Loaded Papers - A Versatile Medium for Sampling and Standardization
Authors: Law Stephen L. , Campbell William J. 
Published: March 2019

AbstractResin-loaded papers composed of approximately 50% cellulose and 50% ion-exchange or chelating resin provide an ideal matrix for many X-ray spectrographic analyses. Standards are prepared by multiple filtration of solutions of known composition through the paper to achieve quantitative collection or by the use of a radiotracer as a monitor for nonquantitative collection. Solutions prepared fram unknown samples are processed in the same manner as the standards.Advantages of the resin-loaded papers are: reduction of interelement effects because standards and unknowns are present in a similar low X-ray absorbing matrix; physical parameters such as metallurgical history, grain size, and surface preparation are eliminated; and sampling errors are significantly reduced and sensitivity greatly increased by concentrating trace elements separated from large samples.Application of these papers to a variety of metallurgical, geological, and water samples will be summarized. The possible use of resin-loaded papers as standards for air pollution monitoring will be examined.
Theoretical Formulas for Film Thickness Measurement by Means of Fluorescence X-Rays
Authors: Shiraiwa Toshio , Fujino Nobukatsu 
Published: March 2019

AbstractThe fluorescence x-ray method of the coating thickness measurement is theoretically studied. The theoretical formulas of the fluorescence x-ray intensity from the coating and from the substrate are obtained which include the enhancement effect between the coating and the substrate. The formulas are applied to the following examples and are confirmed experimentally: zinc on steel; tin on steel; aluminum on steel and on PMMA. The experimental results agree well with the theoretical results.
Unusual Matrix Fluorescence Effects in X-Ray Fluorescence Analysis
Authors: Criss J. W. 
Published: March 2019

AbstractOn the basis of fundamental-parameters calculations of x-ray fluorescence intensities, it is predicted that relative intensities much greater than one can be observed from thick, homogeneous samples. That is , the intensity of a particular line from a mixture of two or more elements can be much greater than the intensity from the pure element. Similarly, the intensity from a mixture of compounds can be greater than the intensity from a pure sample of the compound containing the emitting element.
Computer Code for Analysing X-Ray Fluorescence Spectra of Airborne Particulate Matter
Authors: Drane E.A. , Rickel D.G. , Courtney W.J. , Dzubay T.G. 
Published: March 2019

During recent years energy dispersive x-ray fluorescence (EDXRF) has been used to measure the elemental content of atmospheric aerosols. The code described here is used to reduce EDXRF data and determine the elemental composition of samples collected on membrane filters. The program has been specifically written for EDXRF analysis of size-fractionated aerosols collected by a dichotomous sampler.The x-ray fluorescence spectrometer used in our laboratory employs a pulsed-mode x-ray tube and a lithium-drifted silicon detector. Pulse-height spectra are produced for elements ranging in atomic number from Z = 13 to Z = 82 (corresponding to an energy range from 1.4 to 32.1 keV). Approximately uniform x-ray production is attained by producing independent spectra from three secondary targets (Ti, Mo, Sm).
Energy, Aerosols and Ion-Excited X-Ray Emission*
Authors: Flocchini R.G. , Shadoan D.J. , Cahill T.A. , Eldred R.A. , Feeney P.J. , Wolfe G. 
Published: March 2019

AbstractRapid changes in methods of energy production and utilization are occurring in California, as elsewhere. The affects of such changes upon atmospheric aerosols have been monitored since January, 1973, as part of the continuing study of California aerosols undertaken by U.C. Davis for the California Air Resources Board. A primary goal of the program is to identify aerosol sources in detail, thus allowing energy related components to be isolated and evaluated at many locations throughout the state.Use of ion-excited x-ray emission as the major (although not exclusive) method of elemental analysis is well suited to this program for a number of reasons. Among them include; 1. The sensitivity allows particle-sized aerosol samples to be easily collected, 2. The low cost (under $6, per sample) allows many samples to be run within a fixed budget, 3, The large number of elements seen in the average sample allows source identification by element to element to weather correlations. In addition, the samples are suitable for light element analysis by alpha scattering, for elements H through Cl, thus allowing an inventory to be made of all the aerosol mass in the atmosphere within the size range of the sampler.
NBS*AIDS80: A Fortran Program to Evaluate Crystallographic Data
Authors: Hubbard C. R. , Stalick J. K. , Mighell A. D. 
Published: March 2019

AbstractTechniques for the computer-assisted evaluation of crystallographic data have been developed to improve the data compilations of the NBS Crystal Data Center and the JCPDS—International Centre for Diffraction Data. The resulting computer program, NBS*ATDS80, can be used for the analysis of unit-cell and powder data by the general scientific community as well. NBS*AIDS80 is written in FORTRAN to permit implementation on a wide variety of computers, and input may be from cards or from a terminal. The research and analysis components that will be of use to the individual scientist include the following:1) Calculation of the Crystal Data cell, determinative ratios, and space group for the comparison and reporting of unit cell parameters in a standard setting and for the identification of unknowns.2) Determination of the reduced cell, reduced form number, and the unit cell with the highest metric symmetry.3) Calculation of the molecular weight from the formula using the most recent atomic weights, and comparison of the density calculated by the program with the measured density.4) Generation of d-spacings and indices for any input cell and crystal system.5) Comparison of input powder data with calculated d-spacings, indexing of lines based on known unit cell parameters, and calculation of figures of merit.
An Improved Sample Preparation and Analysis Technique for the Determination of Minor Elements in Catalytic Materials by Radio-Isotope Induced X-Ray Fluorescence
Authors: LaBrecque John J. 
Published: March 2019

SummaryAn improved method for sample preparation and determination of minor elements in catalytic materials by radioisotope induced X-ray fluorescence is presented. The sample preparation is simple and rapid, it utilizes both and internal standard procedure as well as a thin film technique. Synthetic standards are prepared simply by mixing thoroughly the appropriate amounts of the elements of interest as their respective oxides with the matrix and the internal standard. The above standards are used to calculate the relative-fluorescence ratio factors (FJL) for each element of interest relative to the internal standard.Some of the different types of deviations (sample preparation, standard counting, instrumental, etc) will be shown for typical determinations applying experimental methods. Finally the application of this technique for the determination of Cobalt, Nickel, Molybdenum, Platinum and Palladium in catalytic materials is presented.
A Comparison of X-Ray Diffraction Residual Stress Measurement Methods on Machined Surfaces
Authors: Prevey Paul. S. 
Published: March 2019

The two-angle and Sin2ψ methods of x-ray diffraction, residual stress measurement have been shown to yield anomalous results When applied to samples which have been plastically deformed uniaxially in tension or by rolling. These anomalous stresses, which are not true mechanical macrostresses, have been shown to arise from a nonlinear dependence,of d, the interplanar spacing employed for stress measurement, upon Sin2 ψ. A new method of x-ray diffraction stress measurement has been developed by Marion and Cohen which aLlows the separation of the Linear and nonlinear components of the dependence of d upon Sin2 ψ.The two-angle and the Marion-Cohen x-ray diffraction methods are applied to the measurement of residual stresses in the machined and shot peened surfaces of steel and aluminum samples. The results indicate that machining deformation results in a nearly linear dependence of d upon Sin2ψ , and onLy a slight deformation texture. The two x-ray methods yield stress values in ground, turned, and shot peened steel and aluminum samples which agree within the estimated experimental error. Previous results are sighted showing agreement between the two-angle method and a mechanical stress measurement technique. The results indicate that, at least in steels, the multiaxial plastic deformation produced by machining does not significantly effect the accuracy of the two-angle x-ray diffraction stress mea surement method.
Procedures to Run an Automated Micro—Densitometer on a Shared Computer System
Authors: Segmüller Armin , Cole Henderson 
Published: March 2019

AbstractA commercial micro-densitometer is run by an IBM 1800 computer under time sharing. It is used for measuring the transmission of mass spectrometer plates and x-ray powder diffraction films. The x-ray data are processed on the 1800 computer in three steps: First a linear background approximation is performed by least-squares methods, then the data corrected for background are searched for peaks and the position of the peaks is determined. After an optional manual peak selection facilitated by CRT display of the data and results, d-spacings are calculated and printed out together with approximate intensities. The programs are also used for processing data obtained By automated x-ray diffractometers.