bluuebunny/crossref_metadata_2025 huggingface dataset:
Amorphous Solids, Small Particles and Thin Surface Films
Authors: Schossberger F.
Published: March 2019

A comprehensive chart is preserit of the X-ray diffraction effects of gas-and Uquid-like armorphous substances, small particle-size materials, mixtures of amorphous and crystalline compounds, sheetlike crystals, and fibrous materials.

The relationship between the X-ray diagrams and chemical preparations as shown by typical examples from the field of the manufacture of active catalysts cadmium sulfide semiconductors, pour point-depressed lubricants, electroless nickel platings and metal-filled cellulose fibers.

The investigation of thin surface layers formed by chemical reactions required the combination of electron and X-ray diffraction techniques. The usefulness of this combination of methods is demonstrated by a study of black stain formation on cold rolled annealed steel. By identifying the materials in the stain and determining the sequence in which they formed a reaction mechanism between steel surface and annealing-gas can be postulated.
Effect of Penetration On Quantitative X-Ray Diffraction Measurements
Authors: Marburger R. E. , Koistinen D. P.
Published: March 2019

In making quantitative X-ray diffraction studies of quantities such as lattice parameters one generally treats the measured quantity as existing at the sample surface. In X-ray residual stress analyses; large lattice parameter gradients as a function of depth below the sample surface are sometimes encountered and the measured stress (as obtained from, these parameter measurements) is affected toy the fact that the X-ray beam penetrates the sample. In order to accurately evaluate residual stress as a function of depth, it is necessary to consider the "depth of penetration" of the X-ray beam.

The authors have treated this problem by considering the measured stress as an average weighted over the depths from which the diffracted information emanates. By using the observed lattice-parameter gradient as a first approximation, it is possible to set up a theoretical expression for the measured stress with the actual stress at the surface as the only unknown. By equating this to the measured value, it is possible to solve for the value at the surface and thus obtain an equation for the variation of lattice parameter as a function of depth. This process may be used reiteratively to improve the accuracy of the approximation. A specific example of the use of this equation will be presented.
A Method for Obtaining a Quantitative Pole Figure of Stretched Rubber
Authors: Renius Otto
Published: March 2019

Work at the Detroit Arsenal has shown that techniques similar to those employed for the determination of pole figures of metals can be utilized for studying organic materials such a a stretched rubber latex. The rubber, when stretched, forms a preferred orientation pattern which is proportional in intensity to the degree of elongation, and which can be used to plot a pole figure.

A Geiger-counter spectrometer was used to study samples of rubber stretched 600 to 1000 per cent. Using a transmission technique, the specimens were tilted to the impinging X-ray beam in five degree increments while rotating through 360 degrees to allow the measurement of the diffracted beam from the selected atomic planes at various angles within the specimen. The intensities of the diffracted beam at these angles were plotted on a stereographic net to form the pole figures of the (002) and (012) planes of the stretched rubber. The geometry of the sample arrangements permitted the outer portion of the pole figure to be plotted from alpha angle 0 degrees to alpha angle 45 degrees.
Structure of the Solid Oxidation Products of Carbon Black and Graphite as Revealed by X-Ray Diffraction
Authors: Lyon Luther , Harvey D. , Stewart B. , Wallace D. R.
Published: March 2019

Carbon blacks were oxidized by gaseous and wet oxidation techniques. Graphite was oxidized by potassium chlorate dissolved in mixed nitric and sulphuric acids. The resulting oxidized carbon blacks contain 5 to 20% oxygen, 1% or higher hydrogen, and the rest carbon. The oxidized graphite was heated to 200°C at which temperature it explosively forms a material that is very similar to carbon black. The exploded material contains 15% oxygen and the rest carbon. The X-ray work attempts to present a picture of the structure of these materials in terms of per cent disorganized matter, size of crystallites, distribution of thickness of crystallites, and the interplanar distance, according to the methods of Rosalind Franklin and of L. E. Alexander and E. C. Sommer.
A Counting Method for Measuring Single Crystal Diffraction Intensities Using a Weissenberg Camera
Authors: Peterson David T. , Vold C. L.
Published: March 2019

The North American Philips G-M Counting Attachment for use with a Weissenberg camera was modified to achieve greater accuracy and speed in measuring integrated diffraction intensities. The shape, size and divergence of the primary beam was changed to obtain a larger and more reproducible number of counts. The oscillating mechanism was simplified and made more convenient. The receiving slit was enlarged so as to yield integrated intensities which were not affected by the diffraction peak shape. The accuracy and precision of the apparatus was determined by measuring the intensities of equivalent reflections from an ideally shaped crystal of nickel dimethyl glyoxime and by measuring the diffraction intensities from a parameterless structure such as sodium chloride. Very few calculation's are necessary in order to make the proper instrument settings as the necessary angles are read directly from a Weissenberg diffraction pattern.
Determination of Uranium Dioxide in Stainless Steels by the X-ray Fluorescence-Solution Method
Authors: Silverman Louis , Houk William , Moudy Lavada
Published: March 2019

This paper outlines a rapid method for the determination of uranium dioxide in stainless steel by direct X-ray fluorescence analysis after chemical solution of the sample in perchloric acid. A scintillation counter is used to detect the intensity of the radiation. Modifications in the apparatus needed to insure stabilization of the counter are described. Strontium is used as internal indicator. The determination of uranium is unaffected by the presence of large amounts of iron, chromium or nickel at the dilutions described. The counting time for four pairs of counts (uranium and strontium) is about 12 minutes.

A standard deviation corresponding to one-half to one per cent of the uranium dioxide present was observed on synthetic samples ranging from 15 to 25% uranium dioxide.
Applications of the Electron Probe Microanalyzer
Authors: Birks L. S. , Brooks E. J.
Published: March 2019

Applications to nonmetallic specimens such as minerals will be shown and the special techniques required for such specimens described. These include coating the surface with a thin conducting layer and prepho to graphing to map out the areas of interest. Specific examples of copper-iron minerals will be given. Other applications to metallic systems such as mass transfer studies in liquid metal cooling systems will also be shown.
Some Comments on the Beta-Excited X-Ray Source
Authors: Preuss Luther E.
Published: March 2019

The potential of the beta-ray excited X-ray source was evaluated in the search for a small, low energy, planar source for gross apposition studies. Such a. source utilizes the familiar phenomena wherein target impingement by particulate radiation from certain pure beta emitters is utilized for the production o£ useful bremsstrahlung and characteristic X-radiation. Some of the favorable attributes of such a source are; simplicity of design and fabrication, diminutive size, stability, low cost, zero power consutnption and the gamut of synthetic radioisotopes with which they may be powered. This paper deals with the preliminary development of such a beta-excited source for application to apposition radiography as well as with the small, compound source-target.

The design of such a source type is concerned with certain stimulating problems, some of which are; development of adequate photon intensity, reduction of excessive white radiation production, shielding for scattered and spurious radiation, target and source s elf-absorption, Simple illustrations of source-target geometries are reviewed both for compound and separate source-target design. Some resolution studies for the gross apposition source are shown, plus some exposures made with compound sources. The available synthetic isotopes are described and preliminary applications with P32 , Sr90, Y90 and Pm147 sources are outlined. The paper is divided into two portions; one, a brief review of theory and design; two, construction and results for the apposition and compound source.
Components for X-Ray Polychromators
Authors: Jones J. L. , Paschen K. W. , Swain H. H. , Andermann George
Published: March 2019

The use of the Polychromator (multichannel spectrometer) for X-ray analysis allows choice of the optimum combination of slit width, crystal type, focussing circle radius and detector for each of the elements to be determined by the instrument.

Comparisons will be made of various curved and ground crystals such as quartz, lithium fluoride, sodium chloride and ADP used in a focussing spectrometer. The effect of the width of the entrance and exit slits upon resolution, line intensity and line-to-background ratios will be discussed. Gas filled detectors such as Multitrons, flow proportional counters and Geiger counters will be discussed as to the effect of the filling upon efficiency and upon their use with counting or integrating techniques. Limits of detectability for various elements with optimum combinations of the above components will be reported.
Part II-Description of X-Ray Double-Crystal Diffractometer Combining X-Ray Microscopy and Diffraction Analysis
Authors: Weissman Sigmund , Turner Kenneth A.
Published: March 2019

The following pages are devoted to the description of the instrument by which the method described in Part I can be implemented.

Referring to Figures 1, 2 and 3, numeral 1 designates a collimator through which the primary beam P passes, emerging from an x-ray diffraction tube (not shown). Collimator 1 is fitted with a slit system which is adjusted by adjustment screw 2, controlling thereby the divergence of the x-ray beam. The collimator support 4 is attached to the base plate 5. The height and inclination of the collimator support with respect to the base plate is adjustable, so that the instrument can be adapted to various commercial diffraction units. Locking screw 6 locks the height and locking screw 7 locks the tilt of the collimator support.
Some X-Ray Observations on the Oxidation Characteristics of Binary Niobium Alloys
Authors: Hiltz Ralph H.
Published: March 2019

Present knowledge of the effect of alloying on the oxidation characteristics of niobium is limited almost entirely to oxidation rate and oxygen diffusion rate data. In an effort to determine the mechanism by which alloying elements increase or decrease the oxidation rate of niobium, an x-ray study of niobium alloys was performed. Both x-ray diffraction and fluorescent studies were conducted on the base metal before and after oxidation, on the scale formed, and on the interface between the metal and the scale. From the data obtained, a definite description of the mechanism was not possible, but it appears that the Nb0 film between the metal and the Nb203 scale is the rate controlling factor. The elements Ti, Mo, Cr, W, and V which produce a substantial improvement in oxidation resistance effect the formation of a second oxide structure within the Nb0 film. All the elements which provide a measurable increase in oxidation have either a similar ionic size or a +3 valence state and in most cases have both. Elements not having a +3 valence state or similar ionic size, i.e., Cu, Mn, Si, and Zr, do not improve oxidation resistance, in fact Si and Zr act to eliminate the Nb0 film and the oxidation rate of these alloys is greater than pure niobium.
Determination of Uranium in Flotation Concentrates and in Leach Liquors by X-Ray Fluorescence
Authors: Smithson G. L. , Eager R. L. , Van Cleave A. B.
Published: March 2019

X-ray fluorescence has been applied to the analysis of flotation concentrates obtained from pegmatitic uranium ores occurring in Northern Saskatchewan. It has been found necessary to use an internal standard such as strontium or yttrium. The time required for an analysis, as compared to that of conventional chemical or U.V. fluorescence methods, is considerably reduced and flotation pilot plant operations can therefore be more effectively controlled. The method has been extended to include the analysis of sulphate liquors obtained from the leaching of pegmatitic ores and their flotation concentrates. The amount of iron present in the samples is also determined by reference to the internal standard used for the uranium. This additional information is useful in assessing the efficiency of various flotation and leaching techniques.
X-Ray Spectrographic Determination of Uranium and Plutonium in Aluminum and Other Reactor Fuel Materials
Authors: Lambert Maurice C.
Published: March 2019

Several instrument modifications are described including a shop-built turret mount which provides four water-cooled sample compartments, each accommodating samples up to 1.75 inches in diameter by 1.75 inches long.

Sensitivity for detection of the elements throughout the Periodic Chart is discussed for several counters.

Uranium and plutonium have been determined up to 20 w/o in metallic samples of aluminum alloys with a precision of ± one per cent in less than three minutes counting time. The determination of uranium dioxide in cryolite involved powder samples and the use of an internal standard. Uranium dioxide dispersions in bismuth metal were very heterogeneous; they were dissolved and precipitated to provide homogeneous, powders which were analyzed by measuring the intensity ratio of uranium and bismuth fluorescence.

X-ray fluorescence has been used to measure aluminum cladding thickness over plutonium alloy cores. Precision is discussed in terms of cladding thickness, aperture size, and counting time. Thickness of 11 w/o and 14 w/o plutonium-aluminum and enriched uranium-aluminum cores in reactor fuel plates has been measured by X-ray absorption in the range 0.010 to 0.030 inch with a sensitivity of ± 0.00025 inch.
Recrystallization Studies of High Purity Aluminum Single Crystals
Authors: McCune Robert A. , Leighly H. P.
Published: March 2019

The two basic recrystallization theories, that of oriented growth and tliat of oriented nucleation, have been reviewed in light of data obtained from growth of single grains into strained single crystals of high purity (99.99%) aluminum. It appears that a compromise of these two theories would best explain the results obtained under this investigation. Basically, the proposed theory states that a stress is developed between coherent embryo nuclei and the strained matrix crystal. The relative orientation of the embryo nucleus and the matrix coupled with the residual stress in the strained matrix crystal will determine the magnitude of the stress between the embryo arid the matrix. When this stress is of sufficient magnitude, the coherent bonds between the embryo and the matrix will rupture and the embryo will become a nucleus which can then grow and consume the matrix.

Competing with this process is the phenomenon known as polygonization. Partial relief of the residual stress in the sprained crystal takes place as polygonization occurs. This partial stress relief is often sufficient to prevent the formation of nuclei and the occurrence of subsequent recrystallization.
Applications of Optical and Electronic Dispersion to X-Ray Absorption-Edge Spectrometry
Authors: Dodd Charles G.
Published: March 2019

The applications of X-ray emission or fluorescent spectrography to chemical analysis have increased spectacularly in recent years, but little attention has been paid to the potentialities of X-ray absorption techniques. Monochromatic X-ray absorption-edge spectrometry, in particular, is most promising. The ultimate sensitivity of absorption-edge spectrometry probably will be less than that of fluorescent analysis, but this disadvantage may be outweighed by the convenience, economy, and absence of matrix effects with the former method. Both methods appear limited in application only to certain elements.

A pulse height analyzer coupled with scintillation and proportional counter detection has been found to permit an increase in sensitivity of absorption-edge spectrometry, primarily because controlled window widths may be utilized in determining transmitted X-ray intensities with a sealer. Further work has led to the development of a new rapid, convenient technique known as “differential pulse amplitude distribution (PAD) peak height analysis.” Work carried out during the development of the new method is described.
The Universal Vacuum Spectrograph and Comparative Data on the Intensities Observed in an Air, Helium, and Vacuum Path
Authors: Miller D. C. , William Zingaro P.
Published: March 2019

Equipment is described whereby comparative measurements were made on the relative absorption of air.helium, and vacuum for the softer radiations which are of interest in furthering the range of sensitivities of the X-ray spectrograph. Data on magnesium, aluminum, and silicon and shorter wavelengths are presented.
The Norelco Portable Spectrometer (Portospec)
Authors: Miller D. C.
Published: March 2019

A light-weight portable X-ray spectrograph is described in some detail. The analyzing head, weighing only 18 lb, contains a goniometer, ratemeter, and Geiger counter detector. It also contains a special window-type X-ray tube with a gold target which has been developed specifically for this spectrograph, and which provides a very high efficiency of excitation of the sample. An associated power supply contains an rf source providing 40 kv at 60 μa together with the necessary voltages for the rectifier filaments, the X-ray filament, and the Geiger counter voltage. It will detect wavelengths from atomic number 23, vanadium, to atomic number 50, tin, and then using the L series from atomic number 58, cerium, to atomic number 92, uranium. Sensitivity and some applications are discussed.
The Establishment of A Q Rating Factor for Decorative Chromium Plate by X-Ray Fluorescence
Authors: Keesaer William C.
Published: March 2019

Procedures and methods employed to develop anX-ray emission spectrometer technique for determining the quality of decorative chromium plate are presented. Individual plate quality factors and their significance are discussed:

1.

Plate thickness

2.

Plate density

3.

Plate corrosion resistance

Geometric instrumentation changes to the General Electric XRD-5S spectrometer are detailed. These alterations have made it possible to take more complete advantage of the nondestructive nature of the fluorescent method, and have also yielded an increase in useful radiation intensity of 50%.

The unsuccessful attempts to employ commercially plated Hull-cell-type test panels as “standards” are described, along with the satisfactory application of fabricated standards of vacuum vapor-deposited high-purity chromium, laminated to spectrographically pure nickel foils. The merits and limitations of the resultant “absolute purity — absolute density” standard curve are shown and are related to other measurement techniques and accelerated corrosion test data.
Count Distribution and Precision in X-Ray Fluorescence Analysis
Authors: Heinrich Kurt F.J.
Published: March 2019

The statistical fluctuations of photon counts arediscussedas a factor limiting the precision of the analytical result. Assuming a Poisson distribution, the theoretical standard deviation of the result can be calculated. While this prediction does not consider causes of variation other than the count statistics, it is useful in developing methods and checking instrument reliability. Practical examples using experimental results are given.
The Direct Determination of Vanadium and Nickel in Crude Oils by X-Ray Fluorescence
Authors: Lopp Victoria R. , Claypool C. G.
Published: March 2019

A rapid method has been developed for the determination of vanadium and nickel in crude oils in concentrations above 5 ppm. Duplicate analyses for both nickel and vanadium require only one hour, and excellent precision is obtained. At a concentration level of 100 ppm of vanadium, the standard deviation is 3.1 ppm, and at a level of 30 ppm of nickel, the standard deviation is 1.6. The results are comparable to those obtained by spectrophotometric and optical emission spectrographic analysis.

Conversion of the crude oils to greases by the addition of aluminum stéarate minimizes the usual difficulties of handling liquid samples in the conventional-geometry fluorescent X-ray spectrometer. Scattered tungsten emission lines from theX-ray tube serve as internal standards to correct for instrumental and matrix variations.

A new sample tray that permits the insertion of four samples into the instrument at a time has been constructed. Each sample can be moved into position for analysis without opening the sample chamber, making it necessary to waitfor the helium to sweep the trapped air from the X-ray path only once for each four samples.
X-Ray Spectrographic Analysis of Manganese Nodules
Authors: Gordon George M. , McNely Donald J. , Mero John L.
Published: March 2019

Manganese nodules obtained from the ocean bottom are a vast potential source of minerals. These nodules, whose composition depend on their source, have an average composition of about 20% manganese, 14% iron, and 0.5% each of cobalt, nickel, and copper.

X-ray spectroscopy was investigated as a method for the analysis of the nodules, and analytical control during the process of extracting and recovering the minerals.

The basic borax fusion technique of Fernand Claisse (R. P, No. 327, Department of Mines, Quebec) was used. The influence of matrix elements was determined and corrections applied. The binary systems in borax were compared with the curves calculated from pure metals using the methods and calculations of Beattie and Brissey.

The results indicate that the fusion method is sufficiently rapid and accurate for use in the control analysis of manganese nodules.
Differentiation of Several Related Ceramic Bodies by X-Ray Diffraction
Authors: La Forge Louis H.
Published: March 2019

For some vacuum tube work, it was desired to establish a reliable and moderately rapid means of differentiation among several related ceramic bodies, mostly among the high aluminas. Matured composition from a crystallographic standpoint was of primary interest; source and batch constituents were sought only as additional information for interpreting results on the matured ware.

Since Al2O3 represented the major crystal phase in most bodies, the indicators of difference were the minor crystal phases. A number of X-ray diffraction techniques were tried, as were machines of different manufacture. Camera studies with powdered samples were generally ineffective. Useful data were obtained using the Geiger tube—goniometer setup with experimentally determined settings for sensitivity, circuit time constant, sweep rate, beam and receivingslitwidths, etc. Fixedposition peak-height counting was much slower, not practically better for peak-height determination, and introduced chances of missing peaks unless they were first determined by scanning and recording, thus further lengthening the analysis time considerably.

Satisfactory results have been obtained on a number of the bodies of interest. Generally, those bodies which are not differentiated by the X-ray technique outlined are not markedly differentiated in the vacuum tube application.
X-Ray Methods for Detection of Lattice Imperfections in Crystals
Authors: Gerold Volkmar
Published: March 2019

Two methods are described for the detection of lattice imperfections of different kinds.

1.

Imperfections in Solid Solutions. Normal diffraction methods with monochromatized X-rays are applied to single crystals of supersaturated solid solutions, where preprecipitation states occur. The calculated intensity distribution for a one-dimensional model of clustering shows the influence of atomic distribution and lattice distortion. Results are given on the structure of clusters in aluminum-rich alloys.

2.

Detection of Dislocations in Nearly Ideal Crystals. A method first given by Barth and Hosemann is improved and used for the detection of dislocations in crystals of germanium. Use is made of the anomalously low absorption coefficient existing for X-rays which make the Bragg angle with a certain set of lattice planes going through a perfect crystal. The absorption is increased at points where the lattice planes are distorted by a dislocation line, and shadows from these lines can be seen on a photographic plate behind the crystal. The method gives information on the spatial distribution of dislocation lines and the direction of the Burgers vectors,
Precision X-Ray Stress Analysis of Uranium and Zirconium
Authors: Wooden B. J. , House Lt. E. C. , Ogilvie R. E.
Published: March 2019

The feasibility of using X-ray diffraction methods to measure residual stresses in uranium and zirconium (Zircaloy-2) was investigated. A precision method was developed for the determination of diffraction peak positions and the precision associated therewith. The statistical tables of Fisher and Yates were used to determine what order polynomial provided the best least squares fit within the known precision of the observed data. It was found that a second-order polynomial provided an adequate regression. With the aid of a desk calculator less than 5 min calculation time is required to determine the peak position to a precision of ±0.01°.

The stress constant for uranium was determined to be 1308 ± 110 psi/0.01° shift in Δ2θ for copper radiation on the (116) planes at 2θ = 158.3°. The stress constant for Zircaloy-2 was determined to be 430 ± 1 psi/0.01° shift in Δ2θ for chromium radiation on the (10,4) planes at 2θ = 156.4°.
Crystallite Size and Particle Size Measurements on BeO Powders by X-Ray Methods
Authors: Bartram S. F.
Published: March 2019

As part of a study on the fundamental properties of BeO, the surface area, particle size, and crystallite size of BeO powders prepared from different source materials were measured. The results obtained by means of small-angle X-ray scattering and X-ray line-broadening have been compared with electron micrographs and surface area values by air permeability, nitrogen adsorption, and water-vapor adsorption.

Small-angle scattering data were analyzed to yield particle size distribution curves as well as surface areas for various calcined BeO samples. Line-broadening measurements were made to determine mean crystallite dimensions of these same materials. By using both photographic film and automatic recording techniques, crystallite sizes from about 50 to over 5000 A were estimated. The rate of growth of BeO crystals from beryllium hydroxide, beryllium sulfate, and beryllium oxalate source materials has been followed by these complementary techniques.
Design and Applications of a Variable-Temperature Diffractometer Specimen Mount
Authors: Baun William L.
Published: March 2019

A design is described for a variable-temperature diffractometer specimen mount developed internally in the Physics Laboratory of Materials Central. Temperature capability of 1600°C is achieved using Indirect radiation heating. Higher temperatures may be obtained by directly heating the sample. An adaptation allows operation at temperatures as low as −196°C and is useful for studying low-temperature phase changes and examining materials normally liquid at room temperature. The mount operates in vacuum or inert atmosphere. A full 180° 2θ scanning range is possible through the use of curved beryllium- or aluminum-foil windows. Realignment of the sample at temperature and under vacuum may be accomplished from four points around the front plate of the mount. Only two vacuum seals are used In this mount in addition to the window seal and thermocouple seals. Power for the mount is high current, low voltage, and is controlled by an automatic temperature regulator and sensing device which maintains an accurate preset temperature.

Applications of variable temperature techniques on refractory metals, alloys, and compounds are shown, along with an example of low-temperature effects in materials normally liquid at room temperature.
X-Ray Absorption Measurement of Steam Voids in Water at High Pressures
Authors: Martin G. E. , Grohse E. W.
Published: March 2019

X-ray absorption, having been earlier demonstrated to be a unique tool for the accurate measurement of density profiles within gas-fluidized solid systems such as those employed in the chemical and related industries, is being applied to the measurement of steam voids in water flowing through electrically heated rectangular stainless steel channels under conditions of pressure, temperature, flow rate, and heat flux corresponding to “local boiling” (subcooled water) as well as “bulk boiling” (saturated water) in the coolant channels of water-cooled nuclear reactors.

A balanced dual-beam photometer system is employed. A dual-beam X-ray tube and two scintillation-crystal-photomultiplier-tube detector probes are mounted in a manner permitting remote-operated traversing of the test channel in the horizontal as well as vertical directions. The photomultiplier tubes are used in a difference circuit with one of the tubes monitoring the test channel and the other a remoteoperated reference wedge. The difference-measuring connection offers common made rejection so that any differential output Is due to a change in attenuation of the testchannel beam. This output is fed through a differential amplifier to a strip-chart recorder.

With a test channel consisting of 0.020-in-thick stainless steel walls, backed by 0.062-in. beryllium windows for strength, void concentrations within a 0.250-in, thickness of water currently can be measured with an absolute accuracy of 2% or better (which is far superior to that obtainable with previous techniques) and further improvements in accuracy appear likely. The test channel is enclosed in a heavy steel housing with windows, permitting void measurements to be made at pressures up to 2000 psia.
Pulse-Height Selection in X-Ray Fluorescence
Authors: Heinrich Kurt F.J.
Published: March 2019

Pulse-height analysis is a valuable tool in X-ray fluorescence analysis, both for qualitative and quantitative purposes. The elimination of higher order interferences permits determinations that would otherwise be very difficult or impossible, The systematic application of pulse-height analysis in qualitative work greatly simplifies the interpretation of complex spectra. In certain cases one can apply nondispersive analysis, relying on the pulse-height analyzer alone for separating energy levels of X-ray photons. Technique and limitations of pulse-height analysis will be discussed.
The Effects of Operating Variables in the Application of Multielement Calibration
Systems for Fluorescent X-Ray Spectrographic Analyses of Mineral Samples
Authors: Salmon Merlyn L.
Published: March 2019

A highly simplified multielement calibration systemfor semiquantitativeanalyses of mineral samples by fluorescent X-ray spectrography was discussed at the Eighth Annual Conference on Applications of X-ray Analysis. This system relates scattered radiation intensity (background) with peak intensity as measuredon a chart recording to determine concentrations of several elements in a sample.

A continuation of the study reveals the effects of operating variables such as: (1) sample preparation and choice of sample type, (2) operating power and target choice of the X-ray tube, (3) collimation ratio, (4) goniometer scanning rate, (5) choice of method for measurement of background intensity, and (6) control and adjustment of detector, sealer-ratemeter, recorder, and other electronic circuits.

The over-all effects of some operating variables are negligible owing to the compensatory nature of the calibration system. The net effects of others can be directly attributed to particular operating conditions, and these conditions can be controlled to achieve an optimum balance of effects to yield the desired results for accuracy, time required to complete the analyses, and other important requirements in the analyses of minerals.
Fluorescence Analysis of Trace Amounts of Hafnium in Zirconium Using a Silicon Crystal
Authors: Parks J.C. , Plackmann D.G. , Beyer G. H.
Published: March 2019

The proper choice of an analyzing crystal sometimes makes It possible to suppress second-order reflections which interfere with X-ray fluorescence analysis. Some of the problems associated with the analysis of small amounts of hafnium in zirconium, using a silicon crystal and a pulse-height analyzer, are discussed.
An Application of X-Ray Fluorescent Spectrography to Columbium Alloy Melting Practices*
Authors: Moroz D. , Fornwalt D. E. , Aconsky S. , Doyle J. , Clough W. R.
Published: March 2019

Techniques were developed and statistically evaluated for the determination of both the homogeneity and the elemental compositions of columbium alloy ingots. X-ray fluorescent spectrography and automatic data handling systems are utilized. Sample preparation is discussed in detail from the consumable-electrode arc-melt process to the final physical form suitable for X-ray fluorescent spectrography. Arrangements of apparatus for obtaining, recording, processing, and interpreting data, with specific attention to limitations for various matrices, are treated at length.

The method has been applied to specific cases with, for example, a correlation of the degree of variation of homogeneity of columbium alloy ingots with remelting practice. An attempt is made to provide a preliminary basis for determining the value of the technique as a possible means of quality control.
A High-Speed, Selective Uniform-Particle-Size Grinder for the Preparation of Analytical Samples
Authors: Pitchford A. H.
Published: March 2019

Uniformity of particle size is most critical iti both X-ray spectrographic and diffraction samples. This is especially true when there are both hard and soft materials in the sample. The soft material reduces to a smaller particle size and therefore presents a great density and area to the X-ray beam. Accurate quantitative determinations are most difficult under these clrcum s tances. This paper decribes a means of grinding to a more uniform particle size and presents graphic data on the effects of particle-size variation.
Determination of Zinc Sulfide and Cadmium Sulfide in Solid Solutions of Small Single Crystals Used for Semiconductors by X-Ray and Chemical Methods
Authors: Chan Frank L.
Published: March 2019

Single crystals of cadmium sulfide and zinc sulfide have been grown and studied intensively by the Solid State Physics group at the Aeronautical Research Laboratory. The physical phenomena such as reflection, transmission, ultraviolet-excited emission, and electrical resistivity have been observed and characterized on single crystals of these sulfides. Much interest concerning these phenomena has also been centered on single crystals containing both cadmium sulfide and zinc sulfide.

For research purposes, mixed crystals as small as a few tenths of 1 mg or less, to 0.5 g of the mixed sulfides, are being prepared. Special chemical methods are required to determine these constituents in them quantitatively. At times, these chemical methods are not applicable, since these methods invariably consume the sample, and, as a result, other observations on the same crystals cannot be performed.

Changes in lattice parameter in single crystals of mixed sulfides as compared to pure zinc sulfide or cadmium sulfide provide excellent means for the determination of the percentage of these sulfides. In the X-ray method, single crystals used for the determination of the lattice parameters remain intact. The equipment adopted, procedure used, and the data obtained are illustrated and discussed.

In the present study, crystals of cadmium sulfide (greenockite), alpha-zinc sulfide (wurtzite) and solid solutions of these two sulfides having a hexagonal unit cell were used. Since the lattice parameter a0 is found to follow Vegard's law, single-crystal rotation photographs described in this paper were obtained by rotating crystals around the c axis; the lattice parameter was determined with high precision by scanning along the zero-layer line with a microphotometer.
Determination of Thermal Expansion by High-Temperature X-Ray Diffraction
Authors: Vaughan Dale A. , Schwartz Charles M.
Published: March 2019

Two high-temperature X-ray diffraction cameras are described which have been employed at Battelle to determine thermal expansion of metals and ceramic materials. Specimen preparation and temperature measurement and control are described. Lattice-parameter data vs. temperature are presented for uranium, uranium dioxide, and magnesium oxide.
Effect of Impurities on Kaolinite Transformations as Examined by High-Temperature X-Ray Diffraction
Authors: Wahl F.M.
Published: March 2019

The high-temperature continuous X-ray diffraction technique has been used at the University of Illinois for several years in our investigation of structural transformations and the development of phase minerals as natural materials are heated. Of particular interest are the effects which chemical impurities have on predicted structural transformations at elevated temperatures.

The formation of mullite and beta-cristobalite as they develop from the clay mineral kaolinite is examined by continuous X-ray diffraction up to 1450°C, and the influence of added impurities either to enhance or to retard nucleation of these phase minerals is shown. The 2θ range containing diagnostic peaks of both the initial material and of the transition and phase minerals which develop on heating was continually traversed, thus providing a constant record for comparing structural changes vs. temperature.

The furnace used is described in detail, and the effects of added impurities on kaolinite transformations are evaluated to show their importance in controlling the thermal history of a natural material under nonequilibrium conditions.
Projection Microscopy and Microanalyses*
Authors: Poen Ong Sing
Published: March 2019

Results of recent experiments on microanalyses with an X-ray projection microscope will be reviewed. As the use of monochromatic radiation is imperative, spectral analyses of the point source were carried out. A simple stationary divergent-beam-type transmission spectrograph was used. The shape and size were miniaturized to fit in the specimen holder of the Norelco projection unit. Emission spectra from clean, targets and the fluorescent radiation emerging from a 10- to 50-μ-diameter spot of contaminated targets and of two-layer targets will be shown. The spectra were recorded photographically. In addition, a proportional counter, in combination with the R.C.L. 128-channel pulse-height analyzer, was used for measuring the ratio of “white” to line radiation.
Determination of Trace Elements in Plant Material by Fluorescent X-Ray Analysis
Authors: Lytle F.W. , Dye W.B. , Seim H. J.
Published: March 2019

A method is presented for the determination of trace elements in plant materials. The samples were composed of organic material, which was eliminated by wet ashing, large amounts of group I and II elements, and many trace elements of interest in the concentration range 0.1–100 ppm. An attempt to achieve preconcentration of the trace elements by absorption on cation-exchange membrane (which could have been used directly for analysis) was unsuccessful because of preferential absorption and saturation of the membrane by group I and II cations. Formation of complex-metal anions in acid solution and absorption on anion-exchange resin was more successful, but, because of a lack of precision and incomplete absorption, the technique was inadequate. In the most successful preconcentration scheme, an organo-metallic precipitation was used in a matrix suitable for X-ray analysis. In this precipitate the elements Fe, Mn, Cu, Zn, Co, Mo, Cr, Ni, Ti, V, Ca, Sn, Sc, Ba, and Pb could be quantitatively determined. In many cases the lower limit of detection was 0.01 ppm. The accuracy and precision of the technique were proved by comparison to chemically analyzed samples, recovery experiments, and replicate analyses. The method is generally applicable for the analysis of many organic materials.
On the Use of a Modified Radial Distribution Analysis for Indexing Powder Patterns
Authors: Berndt A. F.
Published: March 2019

A modification of the theory of X-ray radial distribution analysis is presented. This modification can serve as a guide to the values of the unit cell dimensions and may be useful in indexing powder patterns of unknown structures, although the use of trial and error methods is not eliminated. This technique is shown to give consistent results with known structures and is applied to the indexing of powder patterns of Pu3Ru and Pu5Ru3. The powder pattern of Pu3Ru can be indexed on the basis of an orthorhombic unit cell with a0 = 6.216 Å, b0 = 6.924 Å, and c0 = 8.093 Å, and Pu5Ru3 on the basis of a tetragonal unit cell with a0 = 8.092 Å and c0 - 10.023 Å.
X-Ray Diffraction Studies on the Titanium-Nickel System
Authors: Gilfrich John V.
Published: March 2019

X-ray diffraction studies were made on the Ti–Ni system around the stoichiometric composition of the intermetallic compound TiNi to clarify some confusion which has existed about the phase diagram in this region, and to explain some anomalies in the physical properties of this material. Wrought and cast samples were examined at room temperature both before and after heat treatment and at temperatures both above and below ambient. The compound TiNi does exist at room temperature. The phase purity of the particular sample was found to be greatly affected by such factors as minor variations in composition, heat treatment, and method of sample preparation. Some confirming metallographlc and physical property data will also be presented.
The Crystal Structure of ThPd4
Authors: Thomson J. R.
Published: March 2019

The structure of ThPd4 has been determined by X-ray powder methods. It has the simple cubic Cu3Au (LI2) structure a = 4.110 ± 0.002 Å at 80 at. % palladium. Interatomic distances and the range of stability of this compound and of ThPd3 are discussed briefly.
The Characterization of Large Single Crystals by High-Voltage X-Ray Laue Photographs
Authors: Peiser H. S. , Levine E. P.
Published: March 2019

Large single crystals can be examined by conventional X-ray diffraction procedures only at their surface or by destructive sectioning. Within the limitations inherent in polychromatic X-ray photography, high-voltage Laue pictures arc shown to give some information on the internal quality of large crystals.

Asterism in conventional Laue photographs is contrasted, with streaks due to geometric effects in Laue patterns of large crystals. Detail within the streaks reveals subgrain structure. A primary extinction effect can be used as striking proof of good crystals being capable of scattering coherently over large distances.
Oriented Single Crystals of Aluminum for X-Ray Analysis*
Authors: Dhosi Joseph M. , Gazzara Charles P. , Middleton Raymond M.
Published: March 2019

A simple gradient heating apparatus was developed and used successfully in growing oriented single crystals of high-purity aluminum suitable for X-ray dinfraction analysis.
An X-Ray Determination of the Debyewaller Factors for Cu2O and UO2 and the Atomic Scattering Factor for Cu in Cu2O
Authors: Sparks C. J. , Borie B. S.
Published: March 2019

The Debye-Waller factor for CuaO and the atomic scattering factor for copper were determined independently of each other at one temperature from measurements of both the diffuse scattering and the integrated intensities of the Bragg maxima. The scattering factor agreed well with that computed from theory. The characteristic temperature computed from the Debye-Waller factor at 298°K was found to be 182°K. At 88°K its value is 152°K.

Similar measurements of the Bragg maxima with a powder sample of UO2 were not useful because of preferred orientation. However, the diffuse intensity is not so sensitive to preferred orientation and may be used to determine the characteristic temperature. Its value for UO2 was found to be 188°K at room temperature.
An X-Ray Study of the Structure of the Alkaline Earth Oxide Cathode
Authors: Lublin Paul
Published: March 2019

Art X-ray diffraction study has been conducted on the emissive coating (Ba, Sr, CaO) of experimental diodes from which thermionic emission data were taken before X-ray analysis. The tubes were then opened and the oxide protected by special techniques in order to prevent the formation of the hydroxide. In addition to X-ray diffraction, other techniques were used to give a complete description of the structures present.
Applicability of Routine Methods of Crystallite Size Analysis*
Authors: Rau Robert C.
Published: March 2019

Several methods for the routine determination of crystallite size by means of X-ray diffraction line-broadening have previously been reported. Although these techniques have proven useful and reliable when utilized with the single X-ray diffractometer and instrumental geometry used to originally develop the methods, it was not known whether other instruments would provide similar reliability. Therefore a study was performed to evaluate the applicability of routine methods of crystallite size analysis to other X-ray diffraction units. A series of six beryllium oxide powder specimens, whose average crystallite sizes ranged stepwise from about 35 to nearly 3000 Å, were used to test a number of X-ray diffractometers. By using a predetermined diffraction geometry for each instrument tested, measured crystallite sizes were found to be quite reproducible and well within the limits of experimental error. The testing procedure, instrumental conditions, and individual performance results are presented in this paper.
The Preparation of Pole Figures for Polymers by Computer Techniques
Authors: Jones J. W.
Published: March 2019

Preferred orientation in polymers has been studied by preparation of pole figures. The diffraction data are collected on punch tape under the control of a programmer for the orienter which permits step wise or continuous scanning. A computer is programmed to prepare the data for an off-line automatic curve plotter. Several projections are available.
Experiences of X-Ray Analyses in Steel and Ferro-Alloy Production
Authors: Baecklund J.
Published: March 2019

A vesta Steel Works manufactures stainless steel, low-alloy steel, alloys for precision casting, welding electrodes, and ferro alloys. When it was decided in 1958 that a new laboratory for production control was to be built, there was an investigation into different spectrographic possibilities. A combination of X-ray and optical methods was selected, that is, determination of C, P, and S was to be made optically while Si, Ti, and heavier elements were to be determined on X-ray equipment. Specimen taking and specimen preparation techniques were worked out. Certain interelement effects were recorded and methods to correct for them found. Methods to. correct for surface properties in determination of high concentrations have been taken into use. This laboratory has now been in continuous use for more than two years. Statistical data on accuracy, reliability, and continuity of operation are given.