bluuebunny/crossref_metadata_2025 huggingface dataset:
First-Principle Simulation of Ferromagnetism in Gd-Doped Mg2X (X=Si, Ge and Sn)
Authors: Ahmar Y. El , Hallouche A. , Dahani A. , Zaoui A. , Kacimi S. , Haddouche Z. , Djebari M. , Boukortt A.
Published: March 2019

Magnetic phase stability and electronic properties of Gd-doped Mg2X ([Formula: see text], Ge and Sn) were investigated by first-principle calculations based on density functional theory. The present calculations were performed using the Generalized Gradient Approximation (PBE-GGA) and the modified Becke–Johnson (mBJ-GGA). The 4[Formula: see text] electrons’ behavior has been investigated as a function of the Coulomb repulsion [Formula: see text] by varying it from 0[Formula: see text]eV to 8[Formula: see text]eV. The ground state properties for the pure compounds are consistent with experimental values and other theoretical data. All doped compounds are metallic and ferromagnetic with large Curie temperature values. It was found that both exchange potentials ([Formula: see text] and [Formula: see text]) provide a better description of the electronic structures of pure and doped systems than regular GGA and mBJ.
Laguerre–Hahn orthogonal polynomials on the real line
Authors: Rebocho Maria Das Neves
Published: March 2019

A survey is given on sequences of orthogonal polynomials related to Stieltjes functions satisfying a Riccati type differential equation with polynomial coefficients — the so-called Laguerre–Hahn class. The main goal is to describe analytical aspects, focusing on differential equations for those orthogonal polynomials, difference and differential equations for the recurrence coefficients, and distributional equations for the corresponding linear functionals.
Quantitative Phase Analysis in Titanium by X-Ray Diffraction
Authors: Hiltz Ralph H. , Lopata Stanley L.
Published: March 2019

In view of present difficulties encountered in met alio graphic methods of phase analysis of titanium and its alloys, the possibility of utilizing integrated X-ray intensities for phase analysis was investigated. Power Formula variables were calculated for titanium, and relative areas of three alpha and one beta peak were determined. Recorded X-ray intensities were obtained from a large number of titanium specimens. The recorded intensities were analyzed and the results compared with those from metallographic analysis. The errors in the method arising from the nature of titanium, texture and peak overlapping, were studied and where possible, compensated for by adjusting the method of measurement and calculation.
X-Ray Projection Microradiography and Divergent Beam Techniques
Authors: Von Batchelder F. W.
Published: March 2019

The topics to be covered are X-ray projection imcroradiography, which embodies the examination of thin poly crystalline sections with the aid of a microfocus X-ray unit, and similar divergent beam examination of thin single crystals.

In X-ray projection or shadow microradiography we restrict our interest to the field of metallurgy and typical examples will be illustrated from ferrous and nonferrous alloys. No special techniques are necessary in the making of these microradiographs, which are recorded on industrial fine grain X-ray film, and which are processed and viewed like regular radiographs. A Hilger microfocus unit operated at 45 kv, 250μa, using a Cu target, 40 micron focal spot was employed.

Some preliminary results will be illustrated from our application of the divergent beam technique.to single crystals.
Textures in Extruded Uranium
Authors: Russell R. B.
Published: March 2019

By means of cristallographie (inverse) pole figures for extruded uranium rods and tubes, the effect of extrusion variables on the texture can be examined. The principal variables are: prior texture, billet and liner temperatures, reduction in area, and ram speed. The final texture can be deeply affected by the prior texture, since two extrusions made under the same conditions but with different prior textures can be markedly different.

In general, an increase in extrusion temperature has an effect similar to an increase in reduction ratio. Ram speed has no important effect between 13 and 100 in./min except that a slow ram speed allows more time for recrystallization to occur.

The effect of temperature on texture is the development of a strong 110 axial texture for relatively high temperature (above about 525°C), a strong 010 axial texture for relatively low temperatures (below 400°C), and a mixture of 110 and 010 axial textures at intermediate temperatures, although these textures may be somewhat complicated by 130 axial recrystallization textures.

The variation of axial texture along the extrusion length and parallel to the radius of extruded tubes may be large.

A 900°C gamma-phase extrusion is shown to have a mild 100, 010, 021, 001 texture.
Electrocrystallography of Cobalt and Cobalt-Nickel Alloys
Authors: Quinn H. F. , Croll I. M.
Published: March 2019

Pure cobalt and cobalt-nickel alloys have been plated from simple electrolytic baths with and without additive and with and without ac superimposed upon the dc plating current.

X-ray analysis reveals preferred orientation in the polycrystalline deposits generally and extreme preferred orientation (characterized by [00.2] and [11.0] fiber axes) in the case of those samples obtained with additive-free electrolyte. It is shown that a change in the pH of the bath or the addition of an ac component are equally effective in determining the type of fiber axis in the deposit. The effects on plating texture owing to the use of additive KCNS in the bath are described. Finally, the correlation between the texture and the magnetic properties of the plating Is discussed.
An X-Ray Absorption Technique for Measurement of Coat Weight on Paper
Authors: Murray Haydn H. , Johns William D.
Published: March 2019

An X-ray absorption method was utilized to determine rapidly and precisely the thickness and weight of inorganic coating layers applied to paper. The mass absorption coefficient μ/ρ was calculated for kaolins and substituted in the following formula

where I is the X-ray intensity after passing through a medium whose thickness is x centimeters, I0 Is the X-ray intensity before passing through a medium, μ. is the linear absorption coefficient, and ρ is the density of the absorbing medium.

The film thickness was calculated and related to coat weight. Coated sheets of variable basis weight, utilizing different adhesives and coat weights, were used. The method is rapid and coating thicknesses can be determined with an accuracy of plus or minus 0.5μ and coat weight of plus or minus 0.2 lb. It is believed that the method can be adapted for production control on the paper coating machines.
X-Ray Fluorescence Analysis of Tungsten-Molybdenum Metals and Electrolytes
Authors: Stever K. R. , Johnson J. L. , Heady H. H.
Published: March 2019

An X-ray fluorescence method is presented for the analysis of tungsten-molybdenum solutions. Tungsten and molybdenum metal powders, produced by a fused-salt electrolysis procedure, are dissolved and analyzed for tungsten and molybdenum by using the W La1, Pt La1 intensity ratios. The platinum spectral line from the X-ray tube target serves as a self-internal standard. The sensitivity limit is about 0,05% and in the concentration range of 0.5 to 100%, the accuracy of analysis is within about 2% standard deviation. The technique is also applied to the analysis of tungsten and molybdenum in fused salts and to the determination of several other Impurity elements in these metals.

A double detector modification for the General Electric X-ray unit is described. The detector consists of a double-window flow proportional counter tube backed up by a sealed krypton-filled counter tube. This allows counting of either soft or hard radiation at maximum efficiencies without the necessity of changing counter tubes. Advantages in specific applications are discussed.
Low-Temperature X-Ray Diffraction of Frozen Electrolytes
Authors: Weltman H.J.
Published: March 2019

A low-temperature X-ray diffraction apparatus has been constructed to study structure and structural changes of electrolytes in the frozen state. This apparatus, which is inexpensive and easy to construct, is an attachment to a standard wide-angle diffractometer. Diffraction patterns may be obtained of various types of materials at any temperature from room temperature to −196°C with a control of ±1°C. The diffraction patterns are recorded on a strip-chart recorder as they are being obtained. Thus, this diffractometer method has several advantages over the camera methods usually employed for low-temperature X-ray diffraction work. A unique sample-introduction method is described which ensures a polycrystalline material suitable for obtaining diffraction patterns. Such patterns are shown for various concentrations of salts in water at several low temperatures, phase transformations being in evidence.
X-Ray Studies of Preferred Orientations and Stress-Strain Relations in Rapidly Deformed Copper
Authors: Gainer M.K. , Glass C.M.
Published: March 2019

A stress-strain relationship for copper in the plastic region has been determined by examining the influence of the applied stresses on the grain orientation of shear-formed specimens. Instrumentation was developed to permit accurate grain-orientation analysis of a large specimen by X-ray diffraction without the necessity for deformation or destruction of the specimen.
Thin-Film X-Ray Spectroscopy
Authors: Finnegan J.J.
Published: March 2019

Quantitative de terminations of thickness and composition are presented for 100- to 10,000-A iron-nickel films. Calibration of X-ray intensities with interferometric and calorimetric values give linear plots for films deposited on Mylar or glass substrates. Application of a film-casting technique shows promise of alleviating two of the problems encountered in X-ray spectroscopy, i.e., matrix-effect-caused deviations from proportionality and the lack of standards for calibration of many types of material.
Lattice Spacings in Some Transition Metal Terminal Solid Solutions
Authors: Chessin Henry , Arajs Sigurds , Miller D. S.
Published: March 2019

The lattice parameter-composition curves for several nickel solid solutions and for some chromium and. iron solid solutions are discussed. It is shown that the size effect may be the predominating influence on the change of lattice parameters in these systems. This is demonstrated by comparing observed and calculated data employing various methods. A new scheme for evaluating the atomic size in solid solutions is proposed, based on regarding the atom, as an incompressible core surrounded by a smeared-out compressible volume. The suggestion that classical elasticity theory may be used as a basis for understanding the size effect in solid solutions is justified by examination of the Ag-Pd system for additions of Ag from 0 to 100 at. %.
X-Ray Diffraction Analysis of Aerosols from Exploding Wires
Authors: Barkow A. G. , Karioris F. G. , Stoffels J. J.
Published: March 2019

In this study, X-ray diffraction analysis is used to investigate the composition of aerosols produced by exploding wires with the current surge from a 4000-joule capacitor. Qualitative analyses of aerosols from 15 different metals exploded in air or inert atmosphere indicate that the particles are crystalline with the normal crystal structure and that explosion of noble metals in air and of base metals in argon produces aerosols consisting of metallic particles. Base metals exploded in air produce aerosols consisting primarily of oxides. Nitrides were not observed. An analytical scheme is described for the Cu-Cu2O-CuO mixtures collected on membrane filters from explosions of copper wires in air. The composition of aerosols is determined for various initial voltages (2-18 kv) on the 20-μf capacitor bank for two series of wires. In one, the weight fraction of CuO increases rapidly with voltage until it accounts for almost the entire sample while the Cu2O and Cu content decrease smoothly. In the other, CuO and Cu2O are about equal for explosions above 6 kv while Cu decreases. Differences are attributed to a change in the circuit and mass of wire used.
A High-Temperature X-Ray Diffractometer Furnace Utilizing High-Frequency Heating*
Authors: Franklin E. W. , Lang S. M.
Published: March 2019

The adaptation of high-frequency heating techniques to a vertical diffractometer will be discussed. The heating system functions as a. portion of an integrated system that provides a wide range of atmospheric and temperature control. Some of the design problems and their solutions and operating characteristics of the system will be described. The useful temperature range is from less than 200°C to greater than 1600°C, depending upon the fur-nace atmosphere and susceptors used. Gaseous pressures may be from vacuo of about 10−6 mm to about 30 psia; and, the sample may be heated in oxidizing, neutral, or reducing atmospheres.
Some Aspects of Nondestructive X-Ray Spectrochemical Analysis of Alloys
Authors: Rickenbach J. Robert
Published: March 2019

The paper is divided into two parts. The first section presents a review of three basic methods of X-ray spectrochemical analysis, including the internal standard method, the absolute intensity method, and the ratio method. The applications and limitations of each are discussed briefly. The second section presents the ratio method at length. Included are the methods of acquiring standards, sample preparation, curve plotting, and a discussion of the factors contributing to the precision of the analysis. Various analytical curves are presented and discussed and the sensitivity for minor constituents is shown.
Observations Concerning the Interdiffusion of Cb-1 Zr Alloy with Type 316 Stainless Steel*
Authors: Manzione A. V. , Huegel F. J. , Fornwalt D. E.
Published: March 2019

Optical and electron metaliographic, X-ray diffraction, and electron microbeam probe studies of the interdiffusion of Cb-1 Zr alloy with type 316 stainless steel are reported. Extruded Cb-1 Zr alloy-type 316 stainless steel diffusion couples were heat treated at temperatures of 732, 871, 982, and 1093°C for time periods of US, 400, 900, 1400 hr. In no case was appreciable diffusion observed in specimens heat treated at 732°C for time periods chosen. Diffusion zones based on the systems iron-columbium and columbium-nickel-iron were observed in varying degrees in all other specimens. An activation energy for the rate-control ling process in the growth of the diffusion layers is reported. The growth rates of the observed zones were found to be retarded when these data were compared with data reported by other investigators for the interdiffusion of unalloyed columbiiim-type 316 stainless steel diffusion couples. Postulations arc made to explain this retarded growth rate and also to explain the growth of a nickel enriched columbium-iron-nickel-chromium intermetallic zone adjacent to the columbium.
X-Ray Tube Parameters and their Effects on Fluorescence Analysis
Authors: Dryer H. T.
Published: March 2019

Many variables influence the performance of X-ray fluorescence analysis with regard to speed, precision, accuracy, limits of detection and the elements to be determined. Some of these variables, such as path transmittance, fluorescent yield, and detector efficiency, can be considered constant; however, the primary X-ray beam cannot be assumed a constant. The intensity distribution vs. wavelength function of the X-ray tube remains the main variable with which the X-ray spectrochemist must concern himself in providing optimum analytical performance and speed.

This distribution is dependent upon target material, window material and thickness, and tube voltage. Though the overall intensity is dependent upon the atomic number of the target material, the wavelengths of the characteristic line spectrum of the target material can provide additional enhancement for elements which absorb such wavelengths readily.

Some of these variables in tube design parameters have been studied to provide comparison performance data on the analysis of a variety of base materials for a number of elements of interest. These data and their interpretation are presented to show how improved fluorescence analysis can be achieved by modifications in X-ray tube design and manufacture.
Oxidation of Zirconium-Yttrium Alloys
Authors: Phalen D. I. , Vaughan D. A. , Richard N. A.
Published: March 2019

The phase and elemental distributions on zirconium alloys containing 5, 10, 25, 35, and 50 at.%. yttrium, oxidized in dry air at 1200 and 1600°C, have been studied by X-ray diffraction, fluorescence, and electron-microprobe techniques. Zirconium-yttrium alloys, which are entirely solid at 1200°C, and zirconium 5 and 25 at.% yttrium alloys, which aire two-phase solid plus liquid at 1600°C, form a multiphase scale of ZrO2, Y2O3, and ZrN. The phase distribution varies with yttrium content, while the average metal composition remains constant throughout the oxide scale and base metal. In contrast, zirconium 35 and 50 at.% yttrium alloys, which are entirely liquid at 1600°C, form a single-phase Y2O3 layer.

The mechanism of air oxidation of solid zirconium-yttrium alloys, up to 50 at. % yttrium, is one of anion diffusion to the oxide-metal interface with little or no diffusion of the metallic elements. The oxidation of liquid alloys differs in that, as a result of yttrium diffusion to the oxide-liquid interface, Y2O3 is the only oxide formed. Ternary Zr-Y-O isotherms are presented to illustrate the phase distribution and mode of formation.
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

Chemical 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

The 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

Measurements 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

As 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

The 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

In 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

A 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

With 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

Demonstrable 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

Resin-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

The 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

On 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).
Determination of the Thickness of Sio2-Layers on Si by X-Ray Analysis and by X-Ray Photoelectron Spectroscopy
Authors: Ebel Maria F. , Ebel H. , Wernisch J.
Published: March 2019

It is feasible to investigate the thickness of oxide layers on silicon wafers by X-radiation in the 0.1-10 nm thickness range. For example, X-ray photoelectron spectroscopy (XPS) is a well applicable technique, with information depth of a few nm. Fig. 1 presents the principle of this method. An impinging characteristic X-radiation hν (e.g. Al Kα) count rate ejects Si 2p photoelectrons from the Si-substrate (d), with count rate n2, which, on their way to the electron spectrometer, have to pass through the SiOx-interface (c), the SiO2-layer (b) and the contamination overlayer (a), whereas Si 2p photoelectrons ejected from the SiO2-layer, with count rate n2 have just to penetrate the contamination overlayer. The Si 2p electrons originating from the SiOx-interface, for the situation shown in Fig. 1, can be added to the substrate count rate.
The Computer Calculation, from Fundamental Parameters, of Influence Coefficients for X-Ray Spectrometry
Authors: Austen C.E. , Steele T.W.
Published: March 2019

A system for the calculation of first-order influence coefficients for any element in any matrix is described in detail. Influence coefficients for either K or L spectra can be evaluated by the method described.
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

Rapid 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.
A Hanawalt Type Phase Identification Procedure for a Minicomputer
Authors: Snyder Robert L.
Published: March 2019

The use of computers to aid in the identification of phases from their powder diffraction patterns was pioneered in the mid 1960's by Frevel, Nichols and Johnson (1-3). Today's most widely used Johnson algorithm conducts a reverse sequential search by comparing each reference pattern in the JCPDS powder diffraction file (PDF) to the unknown pattern. A figure of merit is computed for each match and the patterns with the best figures of merit are listed at the end of the search. The Nichols approach is a reverse search of a singly inverted reference file. An inverted file is one which stores the reference patterns according to the d value of the lowest angle 100% intensity line (d1) . This type of file is analogous to the Hanawalt search books distributed by the JCPDS for manual searching. When an inverted file is stored in a random format, along with suitable disk directory files, only reference patterns containing d1 values of interest need be read in the search.
Qualitative Phase Analysis Using an X-Ray Powder Diffractometer
Authors: Schreiner W. N. , Surdukowski C. , Jenkins R.
Published: March 2019

During the past three years we have undertaken the development of a complete X-Ray Powder Diffraction, facility with the goal of fully integrating experimental and analytical procedures. Such an approach potentially offers substantially improved performance over previously existing systems by virtue of its internal self-consistency and it opens the possibility of significantly extending analytic procedures for both qualitative and quantitative analyses. Our work to date has resulted in improved performance and significant extensions in both areas, and today I will report on those advances in the area of qualitative analysis.
NBS*AIDS80: A Fortran Program to Evaluate Crystallographic Data
Authors: Hubbard C. R. , Stalick J. K. , Mighell A. D.
Published: March 2019

Techniques 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

An 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.
Quantitative X-Ray Fluorescent Analysis Using Fundamental Parameters
Authors: Sparks C. J.
Published: March 2019

A monochromatic source of X rays for sample excitation permits the use of pure elemental standards and relatively simple calculations to convert the measured fluorescent intensities to an absolute “basis of weight per unit weight of sample. Only the mass absorption coefficients of the sample for the exciting and the fluorescent radiation need be determined. Besides the direct measurement of these absorption coefficients in the sample, other techniques are considered which require fewer sample manipulations and measurements, These fundamental parameters methods permit quantitative analysis without recourse to the time consuming process of preparing nearly identical standards.
Energy Dispersive X-Ray Fluorescence Spectrometry at High Count Rates: Pulsed Tube Excitation and Recovery of Resolution by Computer Processing
Authors: Stewart J . E. , Zulliger H. R. , Drummond W. E.
Published: March 2019

Energy dispersive X-ray spectrometry has the potential for making very rapid analyses of multi-element samples. In order to fully exploit this capability several studies have been carried out with the goal of improving performance at high input count rates. A refined amplifier permits operation at input count rates up to 80000 per second with minimal peak shift and distortion. Optimum choice of tube parameters and filters permits utilization of a single Mo transmission target tube to analyze a broad range of elements in minimum time. Use of a pulsed tube further reduces the time required for analysis without sacrifice of precision or resolution. Dead time necessarily increases with increasing input count rate. It can be reduced by selecting a short amplifier time constant, but only with a loss of resolution. Digital processing permits recovery of the lost resolution. Some illustrations are given of spectra that have been processed on-line using a computer based multi-channel analyzer.
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

A 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.
Automated Quantitative XRF Analysis Software in Quality Control Applications
Authors: Klimasara Anthony J.
Published: March 2019

A menu-driven IBM-PC/MS-DOS software system for quantitative XRF analysis was designed combining elements of pattern recognition (spectral “fingerprinting”) with mathematical correction models. The following topics are covered:

-pattern recognition method; N - dimension representation

-local empirical Lachance-Traill or Lucas-Tooth & Price models

-EGA/VGA intelligent driver for a calibration display

-dSASE III Plus “data files - accessed from dBXL/Quicksifver”, dBASE III Plus or from compiled BASIC equipped with “call subroutines”

-Examples of applications (stainless steels and ceramics).

In this approach, experimental alphas are computed utilizing the closest automatically preselected standards from available data files. Alpha values generated in this fashion we term “local alphas”. An intelligent software program is employed which automatically recognizes the resolution of tiie CRT display and delivers the best possible display for the available equipment. This new design also permits the utilization of dBXL/Quicksitver, dBASE III Plus or compiled BASIC resources for additional on site system customization programming. A dBASE III Plus file format is used for XRF data storage. This permits fast data exchange with a local ASCII database and also with all popular spreadsheet formats. Additionally, there are utility subroutines available which allow direct and rapid manipuiation of dBASE III Plus files in compiled BASIC. Application of this software system and graphics to stainless steels and engineered ceramic materials are demonstrated. RIGAKU Smax/PDP-11/73 and TRACOR X-RAY SPECTRACE 5000/Compaq 386 spectrometers are used in these studies.