bluuebunny/crossref_metadata_2025 huggingface dataset:
An Introduction to Total Reflection X-Ray Microscopy*
Authors: McGee James F.
Published: March 2019

The reflection X-ray microscope is a microscope in the conventional sense. X-rays are actually focused in the formation of magnified images of minute objects. Its principal component is a pair of concave glass mirrors whichhave been polished and figured with great care. In common with other optical devices, the reflection X-ray microscope suffers from various aberrations which limit its resolution. Until recently its narrow field and lack of contrast have made it impractical for the examination of histological or metallurgical specimens.

The X-ray microscope has the theoretical advantage of resolution when compared with the optical microscope. While it cannot compete with the ultimate resolution of the electron microscope, it has the advantage of being able to reveal the internal details of objects which are opaque to the electron microscope- Although there is no doubt that the X-ray microscope can contribute to our knowledge of structural details, perhaps its greatest potential lies in its analytical-chemistry aspects. Already a technique exists at unit magnification (contact microradiography) for weighing histological specimens whose cellular structures range from 10−12 to 10−14 g. The enlarged image provided by X-ray microscopy should greatly aid in a more extensive application of the technique.

The above advantages and possible areas of application are a source of continuous stimulation in the development of a reflection X-ray microscope which will operate close to its theoretical limit of resolution.
A Precise Determination of the Atomic Position Parameter for α-Uranium*
Authors: Sturcken Edward F. , Post Ben
Published: March 2019

The new value determined for the parameter was y= 0.1025 ± 0.0003 compared to a previous value of y= 0.105 ± 0.005 deduced by Jacob and Warren. The absorption errors and preferred orientation effects were eliminated and the statistical precision of the measurements was increased by employing a single-crystal diffractometrlc technique.

The cell dimensions were also refined by using the diffractometric technique for high-purity annealed polycrystalllne uranium. Cell dimensions were ao= 2.854 A, bo=5.869 A, and co=4.955 A, all ±0.002 A. Interatomic distances of the twelve nearest neighbors were two atoms at 2.754 and 2.854 A andfour atoms at 3,263 and 3,342 A. The bond lengths were only slightly affected by the changes in y. The main effects of the new parameter are to alter the component of the bond along the b direction by 0.015 A and to change appreciably the calculated relative diffraction intensities.
The Debye Temperature of Carbonyl Iron
Authors: Gazzara Charles P.
Published: March 2019

The Debye characteristic temperature, θ, of carbonyl iron has been determined as being between 433 and 445°K at an ambient temperature of 310°K from an X-ray diffraction study utilizing both monochromatlzed and filtered radiation by both stationary and scanning slit methods.

In computing θ, several factors have been taken into consideration; the diffracted integrated intensities have been corrected for temperature diffuse scattering (TDS); the temperature gradient through the specimen was found to be critical and given as 160°K/in. at 95°K; corrections for the temperature dependence of θ have been made; and extinction effects were investigated, and results contrary to those of U'lna, Krltskaya, and Kurdyumov have been found.

The TDS corrected values for static and dynamic atomic displacements are also given.
X-Ray Studies in the Ti-O System*
Authors: Bright Norman F. H.
Published: March 2019

X-ray diffraction studies have revealed that a titanium oxide with an NaCl-type structure is stable over a wide range of nonstoichiometric compositions, both above and below the 1:1 Ti/O atomic ratio. Attempts to prepare a strictly stoichiometric TiO as a single phase have revealed a marked tendency for such a composition to disproportionate into two nonstoichiometric “TiO”-type structures of variable composition, whereas nonstoichiometric compositions can be readily prepared under similar conditions as single, well-crystallized phases.

The oxide Ti3O5, which forms a constituent of the titanium-bearing slags produced in ilmenite smelting, has been prepared as a pure compound in two different crystalline forms, both monoclinic in structure, but one being very close to the orthorhombic pseudobrookite, Fe2O3 · TiO2, or ferrous dititanate, FeO · 2TiO2 structure. This “dititanate” form inverts to the other monoclinic form at high temperatures. Single crystals of the latter monoclinic form are readily made. The studies of the “dititanate” form have been restricted to powder diffraction work, since it inverts to the other form after melting. The two forms show different oxidation behaviors,
A New Commercial X-Ray Projection Microscope*
Authors: Poen Ong Sing
Published: March 2019

A recently developed Dutch commercial projection X-ray microscope will be described. The principal features are: simplified focusing by using reflected electrons, four different target materials exchangeable during operation, and hlnocular viewing of either the specimen itself or the fluorescent image. The specimen and film chamber is evacuated and the voltage is variable between 5 and 20 kv. Some results will be shown.
Industrial Applications of X-Ray Methods for Measuring Plating Thickness
Authors: Zimmerman R. H.
Published: March 2019

Calibration procedures and data are presented for plating thickness measurements of gold, silver, tin, and nickel on copper, brass, and steel basis metals. Both emission and absorption techniques are described, and examples are given of measurements on thicknesses from 10 to 600 millionths of an inch. The use is shown of masking and integrating techniques for curved or unusual shapes.

For the special problem of duplex platings, which have two metals each varying in thickness, the Kα/Kβ absorption ratio and the Lα/Lβ emission ratio are compared with conventional absorption and emission techniques.

Optical and chemical determinations are shown to be less precise as well as considerably slower than X-ray measurements on the same piece. Examples are given of the use of X-ray measurements to study fundamentals of plating processes, such as barrel-plating thickness distributions and variation of thickness across a surface, as well as to study processes such as wear or porosity.
Routine Crystallite-Size Determination by X-Ray Diffraction Line Broadening
Authors: Rau R. C.
Published: March 2019

Increasing interest in the sintering characteristics of various ceramic materials has resulted in the need for a knowledge of the crystallite sizes of many constituent ceramic powders. Standard X-ray diffraction line-broadening techniques have been utilized to determine these crystallite sizes. This paper presents a general review of the theory of line broadening as a means of measuring crystallite size and gives the methods and modifications used to perform this type of analysis rapidly and on a routine basis.

Four modifications have been used in the determination of crystallite size routinely by X-ray line broadening. These methods are (1) a graded set of powder photographs, (2) a computer program to calculate sizes from diffractometer data, (3) a set of crystallite-size curves for a given material for use with diffractometer data, and (4) a standard set of curves to use with diffractometer data for any strain-free materials. The preparation, use, and limitations of each of these methods is presented.
Selected Applications of High-Temperature X-Ray Studies in the Metallurgical Field
Authors: Goldschmidt H.J.
Published: March 2019

High-temperature X-ray powder photography has proved of great value in many directions in the metallurgical field. Some of the successes achieved and problems encountered by the author and other investigators using an established-type camera (British Unicam) for temperatures up to 1400°C will be discussed. This will be by way of specific case histories, chosen both for their own scientific interest and to illustrate the techniques employed. The applications concern phase transformations and the measurement of coefficients of thermal expansion in iron and steels, as well as in some nonferrous metals and inorganic compounds.
The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate
Authors: Moore E. L. , Metcalf J. S.
Published: March 2019

High-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.

Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.
A Simple Multielement-Calibration System for Analysis of Minor and Major Elements in Minerals by Fluorescent X-Ray Spectrography
Authors: Salmon Merlyn L.
Published: March 2019

Techniques of mineral analysis by fluorescent X-ray spectrography can generally be classified on the basis of (1) extensive sample preparation and simple instrumental examination, (2) simple sample preparation and extensive instrumental examination, (3) extensive processes for both, or (4) simple processes for both major phases of the technique. The latter type of technique is usually the most commensurate with the concept “maximum information with minimum effort.”

Suitable analytical results with multielement calibration systems for random mineral samples can be obtained if there are valid considerations of the relevant absorption and enhancement effects or if the systems are based on general procedures to minimize absorption and enhancement effects. Preliminary investigation indicated that control of sample mass and use of thin films of the mineral sample is a convenient and simple method of minimizing absorption and enhancement effects.

Successful application of thin-film samples with known masses in a multielement calibration system is highly dependent upon details of sample preparation and comprehensive studies of these details will be discussed.

The calibration system is suitable for the determination of minor and major concentrations in the sample, but it is not recommended for determination of trace concentrations.
Precision of X-Ray Emission Measurements in the Determination of Low-Alloy Steels with an X-Ray Spectrograph*
Authors: O'Neil Robert L. , Neuhardt John B. , Shulhof William P.
Published: March 2019

A large amount of data has been treated statistically to determine daily and long-range variations which occur when replicate determinations are made on low-alloy steel samples. The experiment reported here was designed and run to evaluate the results obtained using an RCA Siemens X-ray spectrograph. As part of a quality-control method for the analysis of low-alloy steels, it was desirable to know the confidence limits for within-day and day-to-day replication. This paper reviews the results of this study and represents an outline of future work planned.
The X-Ray Spectrographic Analysis of Thin Films by the Milliprobe Technique
Authors: Sloan Robert D.
Published: March 2019

Frequently it is desirable to perform an X-ray spectrographic analysis on an area of a specimen which is considerably smaller than that normally irradiated in bulk-production spectrographs. Ideally, one would turn to an electron-beam microanalyzer for this type of analysis. Unfortunately, there are few of us who can justify the expenditure necessary to equip our laboratories with this instrument. Therefore, a compromise measure has been arrived at which permits the analyst to examine an area many magnitudes smaller than that obtainable from production spectrographs and many magnitudes less expensive than that encountered in electron-probe microanalyzer instrumentation.
Equipment for Beam Scanning and Step Scanning in Electron-Probe Analysis
Authors: Wittry David B. , Fitzgerald Ray
Published: March 2019

A versatile beam-scanning system has been developed for use with the Electron Microprobe X-ray Analyzer manufactured by Applied Research Laboratories, Inc. It provides for the display of X-ray intensities from any of three spectrometers, three nondispersive detectors (either counters or scintiallation counters), as well as the current collected by the target or the current backscattered by the target. The electrostatic deflection system does not interfere with the use of the optical-viewing system and provides a maximum scanning area of only slightly less than field of view of the optical-viewing system.

A stepping motor, controlled from the readout console, has also been developed which permits automatic point-by-point analysis of a specimen with minimum operator attention. In the use of this attachement, measurements may be made for fixed time, fixed charge, or fixed counts (integrated intensity) at each point. As a result, the step-scanning motor facilitates accurate measurement of one-dimensional concentration fluctuations and is particularly useful for phase identification and studies of diffusion and segregation.
The X-Ray Investigation of Preprecipitation in Supersaturated Solid Solutions
Authors: Lutts A.
Published: March 2019

This paper briefly traces the study of the preprecipitation or cold-aging stage of the decomposition of supersaturated solutions by means of diffuse scattering of X-rays.

This part of the overall precipitation process is of considerable practical as well as theoretical interest because it is during preprecipitation that changes in many physical and mechanical properties take place without the formation of a precipitate phase.

Examples will be given to show the types of zones encountered during this stage in various age-hardening alloys. These will attempt to illustrate the contribution which the study of diffuse scattering of X-rays, guided by present-day concepts of crystal imperfections, has made toward a better understanding of the precipitation process in alloys.
Recent Developments in the Measurement of Orientation in Polymers by X-Ray Diffraction
Authors: Wilchinsky Zigraond W.
Published: March 2019

From pole figure data, the orientation of a crystallographic direction R in any reference direction Q in a sample can be quantitatively expressed by the average , where σ is the angle between Q and R in a crystal. In general,  can be evaluated in terms of the experimental averages  whereϕhkl is the angle between Q and the normal to the (hkl) planes. The number of independent  measurements needed varies from one to five depending on the crystal system, hkl indices, and other factors discussed. Experimental techniques found useful for measuring  are described.
Specifications and Performance Data for the ARL Electron Microprobe X-Ray Analyzer
Authors: OBrien L. P.
Published: March 2019

Detailed EMX specifications are presented. Performance data obtained on several production instruments are discussed and some future applications of microprobe analysis are suggested.
Continuous Determination of Zinc Coating Weights on Steel by X-Ray Fluorescence
Authors: Dunne James A.
Published: March 2019

The measurement of the area density of zinc coatings on steel by X-ray fluorescence is considered from an instalment design point of view. Each of the two general approaches, i.e., measurement of the attenuation of the iron emission line by the zinc coating and measurement of the sine emission line has limitations. Calculations indicate that contrast requirements are best satisfied by the iron attenuation technique in the coating weight interval 0.2-1.2 oz/ft2 per side. Experimental data collected on galvanised and zinc foil samples are presented in support of this contention. Conversely, advantages in the application of the zinc emission method to very thin zinc coatings are pointed out. Spectral resolution is discussed in terms of the ultimate precision and range of coating weight measurements. For the iron attenuation method, it is concluded that a black plate to infinite zinc intensity ratio of approximately 500 permits reasonably precise measurement of zinc foil coating weights in the vicinity of 1.2 oz/ft2 per side. This requirement can be met through the use of a LiF monochroraator crystal and 5 in. of effective 0.020-in. flat plate collimation.
X-Ray Spectrographic Analysis of Rare Earths in Yttrium-Iron Garnet Powders
Authors: Lloyd J. C. , Kuptsis J. D.
Published: March 2019

Analysis schemes for eleven rare earths (Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb) taken singly in Y-Fe garnet powders are presented. Straight-line calibrations result in all cases, usually over a range from below 0.5 wt.% to better than 6 wt.%. Errors were held to ±5-10% even using extraordinarily simple sample preparation techniques. Data are presented relating to the effects of particle size and sample preparation on precision and accuracy of the resulting analysis.
Absorption Effects in X-Ray Fluorescence Measurement of Elements in Oil
Authors: Gunn E. L.
Published: March 2019

The influence of absorption effects in measuring elements in petroleum oil by X-ray fluorescence can, under certain circumstances, be predicted approximately from theory. Exact information on specific systems and instrumental conditions must practically be provided by experiment, however. The influence of absorption on fluorescent intensity under specific conditions of interest has been studied from three viewpoints; varying the depth through oil of a solid elemental specimen, varying the depth of a solution containing the element dissolved in oil, and varying the amount of the dissolved element in oil over a broad range in concentration. The group of elements selected for study illustrate characteristic fluorescent radiations often1 measured from oil. The experimental results are expressed graphically and are compared between elements as well as with theory. The results have analytical implications which pertain to the quantitative determination of elements in oil by X-ray fluorescence.
Particle Size and Mineralogical Effects in Mining Applications
Authors: Bernstein F.
Published: March 2019

A relationship is derived between X-ray intensity and particle size for a minor constituent in a powder sample. Theoretical and experimental curves are compared for several elements which are of importance in mining applications. Based upon these curves, some general guides are established relating to a method of predicting the particle size required for a given application. It is also shown that the relative intensity of a minor constituent is independent of the absorption coefficient of the matrix, if the particle size of the matrix is constant. Mineralogical effects, which relate to the occurrence of an element in two or more forms of chemical combination, are discussed and several examples in mining applications are cited.
A Systematic Method for Indexing Spots of Single Crystals in Laue X-Ray Photographs
Authors: Konnan Y. A.
Published: March 2019

The determination of the orientation of a single crystal by Laue X-ray photographs is dependent on the identification of the indices of the spots. At the present time, the determination of indices is done by various methods, none of which is entirely systematical. A method for establishing the indices of the spots which avoids a trial-and-error approach is described here. The method is graphical, uses a specially compiled table of erystallographic angles and is not dependent on the complexity of the structure of the crystal or its symmetry. An example of the cubic system is included. With more complex crystal structures the method becomes very laborious and the help of computer methods is suggested.
X-Ray Diffractometric Examination of Low-Temperature Phase Transformations in Single-Crystal Strontium Titanate
Authors: Lytle Farrel W.
Published: March 2019

The lattice parameters of single-crystal SrTiO2 were determined by X-ray diffraction as a function of temperature from 4.2 to 300°K. Three significant regions were found: from 65 to 110°K a tetragonal modification, exists (c/a = 1.00056); from 35 to 55°K, line splitting consistent with orthorhornbic symmetry was observed, and at 10°K an anomalous maximum in the lattice parameter vs. temperature curve was found which suggested a third structure transformation. In the tetragonal region (at 78°K) the formation of a domain structure was observed with a polarising microscope. The low-temperature X-ray technique and X-ray cryostat are described.
Instrumental Developments for Electron Microprobe Readout
Authors: Heinrich Kurt F. J.
Published: March 2019

While conventional X-ray signal readout systems can be used in connection with the electron probe analyzer, new readout techniques can be applied with advantage, particularly for scanning procedures. Several novel techniques involving photographic recordings of oscilloscope tracings will be described. These techniques are applicable to area scanning (enhanced concentration method, concentration mapping with use of X-ray signals, and target current concentration mapping procedures) as well as line scanning. Combinations of area-scanning images with line-scan registration ate used for representing line-scan results.

By using operational amplifiers as signal adders, wavelength scans can be efficiently registered on a Polaroid photogram, with baseline indication and wavelength markers, in a single exposure. Another wavelength scanning technique registers the pulse height of the lines observed during the scanning operation, so that the order of reflection of the lines can be established. The use of an x-y recorder also offers advantages in the registration of line scans. Techniques for registration of multiple scans and for concentration mapping with the x-y recorder will be described.
Detection Confirmation and Determination of Trace Amounts of Selenium by X-Ray Methods
Authors: Chan Frank L.
Published: March 2019

Recently, interest in the determination of selenium in trace amounts has been greatly intensified because of the nutritional aspects of this element. It has been reported that selenium in the amount of 13 μg in the form of sodium selenite in 100 g of feed has an effect similar to that of vitamin E. In the field of semiconductors, the detection and determination of trace amounts of selenium in arsenic, antimony, and small single crystals of solid solution of cadmium selenide and sulfide are of considerable importance in semiconductor performance.

In the Aerospace Research Laboratories, 4,5 diamino-6-tbiopyi-imidine has been successfully adopted as a reagent for the spectrophotometric determination of selenium. The reaction of 4,5 diamino-6-thiopyrimidine and tetxavalent selenium produces a yellow color with the formation of elemental selenium. It is possible to determine elemental selenium by collecting it in a thin layer. The selenium deposited in this layer may then be determined by an X-ray fluorescence method. A procedure of this nature has the advantage of eliminating the matrix effects commonly encountered in X-ray fluorescence. Furthermore, the slow generation of selenium affords a convenient means of detection and confirmation of this element by the use of X-ray diffraction procedures. By this technique selenium is first converted to its tetravalent state and is then reacted with 4,5 diamino-6-thiopyrimidine. On standing, the selenium is reduced to a red precipitate of elemental selenium which can be dissolved in carbon disulfide. Finally, the selenium can be converted into its hexagonal structure by annealing at 205-207°C.
X-Ray Spectrometric Determination of Composition and Distribution of Sublimates in Receiving-Type Electron Tubes*
Authors: Bertin Eugene P. , Longobucco Rita J.
Published: March 2019

During the normal operation of conventional receiving-type electron tubes, certain metallic elements, such as barium, strontium, nickel, and manganese, sublime from the hot cathode and deposit on cooler parts of the tube. This process gradually impairs the performance of the tube and may eventually limit its useful life. This paper describes some applications of a variety of X-ray spectrometric techniques to the qualitative and quantitative analysis of these sublimates and to the mapping of their distribution on various surfaces in the tubes.

All work was done on a standard commercial X-ray spectrometer, but specially designed accessories are described for mounting and rotating small parts in the primary X-ray beam and for confining the beam to these parts. Procedures are given for analysis of microgram deposits on electron-tube cathodes, grids, plates, micas, and bulbs by both nondestructive and filter-paper-disk techniques. Procedures are given for point-by-point mapping of the distribution of sublimates over the surfaces of these parts by use of a commercial “X-ray probe” selectedarea accessory in conjunction with a curved crystal to give increased intensity. Procedures are given for various techniques for calibrating all the analytical methods, including preparation of thin films of known composition.

The results of some typical electron tube studies are described and illustrated. The approximate sensitivity of the methods for determination of total sublimate is, in micrograms per part, 0.1 for barium, strontium, and manganese and 0.05 for nickel. The approximate sensitivity for mapping sublimate distribution with a 1-mm aperture is, in micrograms per square centimeter, 1 for barium, strontium, and manganese and 0.5 for nickel. Although the techniques described are applied specifically to sublimates in electron tubes, they are also readily applicable to analysis of specks and films on other small parts and to thin-film studies in general
The Determination of Thorium in Monazite by Fluorescent X-Ray Spectrometry
Authors: Farquhar M. C. , English M. M.
Published: March 2019

A method is presented for the quantitative determination of thorium in monazite by fluorescent X-ray speetrometry. Strontium is used as an internal standard, and sample preparation consists of mechanically blending the finelyground (325-mesh) sample with reagent grade strontium carbonate. The prepared sample blend is packed into a sample cup and irradiated at 50 kV and 27 mA. A lithium fluoride analyzing crystal is used, and the intensity of the Th Lα1 and Sr Kα peaks are scaled. Intensities are corrected fov background. Calibration is achieved with a single sample of monazite of known thorium content. National Bureau of Standards monazite sample number 2601 (9.65% ThO2) was used in this work. The standard monazite is blended with strontium carbonate, irradiated, and scaled under the same conditions as the sample. The thorium content of the sample is then calculated by the equation: %ThO2 = (R sample) (%ThO2 standard)/R standard, where R = Thcounts/sec/Srcounts/sec. Replicate results agreed within 0.2% ThO2 on six samples of monazite which contained from 4.4% to 6.8% ThO2. Independent results by a second laboratory show no significant difference in precision.

The method was used to determine the thorium content gf several rare-earth materials which contained approximately 0.5% to 1.0% TriOs. The results agree closely with values obtained by gamma-ray spectrometry.
Small-Angle X-Ray Scattering by Metastable Liquid Immiscibility in Glass
Authors: Williams John A. , Phillips Bert , Rindone Guy E. , McKinstry Herbert A.
Published: March 2019

Small-angle X-ray scattering measurements were made on samples of CaO—MgO—SiO2 as CaO-MgO-SiO2glass in which met astable amorphous phase separation had been induced by heat treatment. Glass rods drawn from a melt of composition 30.5% CaO, 8.0% MgO, 61.5% SiO2(by weight) at 1400°C were heat treated for 1, 2, 10, and 15hr at 825°C. X-ray scattering intensities of heat-treated and non-heat-treated samples were measured using an apparatus based on Kratky collimation geometry and equipped with a pulse height analyzer. Particle sizes were calculated from the radii of gyration which were determined from plots of log intensityvs, θ2, according to the method of Guinier. The data show a growth with time of the dispersed spheres from 350 to 1880 Å in diameter and correspond to the growth rate for diffusion-controlled growth of a sphere. Electron micrographs of identical samples prepared concurrently are presented. Inhomogeneity sizes obtained by the two methods are in very good agreement. Results obtained using the Kratky system in conjunction with a pulse height analyzer are compared with those obtained when a slit collimation system and balanced filter monochronmtization were used to study the same sample.
Ternary Carbide Phases Formed by Scandium-Group Elements with Aluminum and Carbon
Authors: Rosen S. , Sprang P. G.
Published: March 2019

A new group of ternary carbide phases which are formed by combination of an element of the scandium group (which is taken to include the rare-earth elements) with aluminum and carbon has been found. These phases are related to the series of T3BCx compounds discovered by Stadelmaier (T for a transition element and B for a B subgroup element). Atomic size effects are discussed which show that T3BCx phases behave in a manner similar to many ordered binary phases of AB3 stoichiometry. There is a readjustment in size of the various metallic components which results in effective radii compatible with cubic close packing. An anomaly which appears when the observed lattice parameters of T3BCx are related to the Goldschmidt radii of the component atoms is discussed in this light. Measurements of the intensities of X-ray diffraction peaks are used to show that the carbon atom in these phases occupies the octahedral hole in the center of a Cu3Au-type unit cell. This position is maintained in alloys which contain varying amounts of carbon.
X-Ray Diffraction of Nonmetallic Phases Chemically Extracted from Columbium Alloys
Authors: Laverty David P. , Hiltz Ralph H.
Published: March 2019

The identification of non-metallic phases occurring in a metallic matrix cannot always be accomplished by standard methods of X-ray diffraction analysis. Separation of the nonmetallic phases from the matrix by chemical extraction, with subsequent X-ray diffraction analysis allows identification of the nonmetallic phases without the problems associated with X-ray analysis of bulk samples.

In one study of alloy carbide dispersions in columbium, X-ray diffraction of the bulk samples could adequately identify the carbides present, but it was only by studying the chemically extracted residues that an important oxygen gettering effect of one of the alloy additions was discovered. In another study, X-ray diffraction work on extraction residues of Cb-Zr alloys showed evidence of a double oxygen gettering effect producing two distinct oxides. In the built sample, some of the diffraction lines produced by one of these oxides were masked by the tines of the columbiurn matrix. Therefore, only by use of an extraction technique were these two oxides identifiable by X-ray diffraction. In a Cb–10Ti–10Mo alloy, X-ray diffraction was used to study the nature of the sub scale formed during oxidation of the alloy. At least two nonmetallic phases were found. By using chemical extraction techniques, the phase responsible for the formation of the subscale was identified as TiO.

These studies demonstrate some of the advantages of the chemical extraction techniques for obtaining samples of nonmetallic phases for study by X-ray diffraction.
A New Focusing Vacuum X-Ray Macroprobe Analyzer
Authors: Dunne James A.
Published: March 2019

A new X-ray probe attachment for the standard Norelco Vacuum Spectrograph has been developed. The X-ray optical design is essentially the same as that of the Norelco/AMR Microprobe goniometer, being an Ogilvie-type varying curvature Johann focusing device. A light optical system which allows the examination of the specimen during analysis is incorporated in a prealigned module along with the X-ray beam defining aperture. This arrangement assures a constant relationship between beam and optical field centers. Apertures ranging in diameter from 50–500 μ are provided. Data are presented giving the effective size of the specimen area analyzed using each of these apertures. A detailed description of the component parts of the instrument is given.
A Polycrystalline X-Ray Analyzing Crystal
Authors: Canon Max
Published: March 2019

Analyses performed have been to determine the feasibility of using pyrolytic graphite (PG) as an X-ray analyzing crystal. Pyrolytic graphite is formed by the pyrolysis of a hydrocarbon, which yields a hexagonal structure graphite with a high degree of anisotropy. After annealing, the anisotropic properties are enhanced even more. For most applications, the intensity and resolution are not as good as with, the best analyzing crystals; however, the extreme durability of pyrolytic graphite makes it a feasible X-ray analyzing crystal.
The Effect of Grating Blaze Angle on the Diffraction Efficiency of Ultrasoft X-Ray Radiation
Authors: Nicholson James B. , Frank Mooney C. , Griffin Gordon L.
Published: March 2019

Spectrum analysis in the ultrasoft X-ray region is complicated by the fact that this radiation is almost totally absorbed in any medium. This has necessitated spectrometer components which minimize this effect. Nondispersive and total reflection techniques, though high in speed, lack good resolution and in the case of the latter, are usually restricted to analysis of elements differing by at least three atomic numbers.

Diffracting media which have proven successful are the long-chain organic crystals and gratings at grazing incidence. The grating is superior to the organic crystal concerning resolution and dispersion and has proven to be comparable arid in some cases better for peak intensity and line-to-background ratios.

Lightly-ruled gratings have been used for many years, but little attention has been given the blazed grating until recently. Since the critical angle of total reflection for a given material is wavelength-dependent, it may be utilized to discriminate against shorter wavelengths and thus improve line-to-background ratios. The optimum conditions for sensitivity, then, would be to relate the input angle to the blaze angle and vary the input angle as a function of wavelength, thereby maximizing the line intensity or the line-to-backgrourid ratio as required.

Several gratings with varying blaze angles and surface finishes are evaluated with O Kα (23.7Å) and C Kα (44Å) radiation.

The importance of groove profile is emphasized by comparing the profile as determined by the electron microscope with the experimental evidence. The variation of diffraction efficiency with wavelength and input angle is then considered theoretically and compared with experimental results.
Lattice Strain Measurements on Deformed FCC Metals
Authors: Macherauch Eckard
Published: March 2019

In this work experiments have been undertaken to determine the type of residual stresses of plastically deformed polycrystals of aluminum, copper, and nickel which cause a shift of the X-ray interference lines. In order to get accurate stress values, the lattice strain distribution has been measured in special planes of the deformed specimens, using the sin2 ψ technique. The surface stresses were determined as a function of the macroscopic plastic strain of cylindrical specimens. With increasing strain, the residual surface stress component parallel to the direction of deformation increases. The stresses observed are compressive ones after tension and tensile ones after compression.

The changes in the residual lattice strain distributions which arise on progressive thinning of the plastically deformed specimens have been measured. From the stress values determined in each new surface layer, the stress distribution originally present in the uodestroyed specimen was calculated. Tensile stresses in the interior of the specimens are in equilibrium with compressive stresses in the surface areas. The formation of residual stresses on specimens with a work-hardened surface layer is found to be quite different from that of well-annealed samples.

The results of this work seem to show that in uniaxially deformed cylindrical specimens, residual macrostresses arise which may be a consequence of a macroscopic inhomogeneity of work-hardening between the surface layers and the interior of the polycrystals.
Correction for Non-Linearity of Proportional Counter Systems in Electron Probe X-Ray Microanalysis
Authors: Heinrich Kurt F. J. , Vieth Donald , Yakowitz Harvey
Published: March 2019

While the theoretical basis for the correction of non-linearity of detector systems is well known, methods for the determination of dead-time effects must be adapted to electron probe microanalyzer systems. Two such methods, one employing both X-ray and current measurements and the other employing simultaneous X-ray measurements on two spectrometers, are described. The effect of pulse-height shrinkage at high counting rates on the linearity of the detector system is discussed. When the proposed corrections for the dead-time of X-ray detector systems employing proportional counters are applied to the X-ray intensity measurements obtained with the electron probe microanalyzer, count rates as high as 50,000 counts/sec can be used.
Homogeneity Characterization of NBS Spectrometric Standards II: Cartridge Brass and Low-Alloy Steel*
Authors: Yakowitz H. , Vieth D. L. , Heinrich K. F. J. , Michaelis R. E.
Published: March 2019

Most modern instrumental methods of analysis depend on the use of known standards of composition for calibration. Newer analytical techniques, such as the solids mass spectrometer, laser probe and, especially, the electron-probe microanalyzer have reduced the amount of a sample which can be analyzed quantitatively to a range of about 0.1 to as small as 0.00005 μg. As a corollary to these microanalytical advances, homogeneity requirements have become severe to meet analytical standards. This paper describes a continuation of the National Bureau of Standards' effort to characterize more fully existing standards as to suitability for the new microanalytical techniques. An NBS cartridge brass sample in both the wrought (NBS-1102) and chill cast forms (NBS-C1102), as well as a low-alloy steel sample (NBS-463), have been investigated by means of electron-probe micreanalysis and optical metallography. Some 17 elements are contained in the brass, while 25 elements are found in the steel. Results for 10 elements in the steel and 6 elements in the brass are presented. In the steel, iron, nickel, copper, and silicon ate essentially distributed homogeneously at micron levels, while manganese, tantalum, niobium, zirconium, sulfur, and chromium are not. In the brass, copper and zinc are distributed homogeneously at micron levels while lead, sulfur, aluminum, and silicon are not. Electron-probe micreanalyzer results indicate that both NBS-1102 and NBS-C1102 brass are suitable for use as a calibration standard for electronprobe microanalysis as well as other microsnalyticat techniques, such as the solids mass spectrometer. The results for brass have been corroborated by a number of laboratories using the electron-probe analyzer.
Electron Microprobe Analysis of Highly Radioactive Samples
Authors: Scotti V. G. , Johnson J. M. , Cunningham R. T.
Published: March 2019

An electron microprobe analyzer shielded and modified to accept for analysis radioactive samples reading up to 100 R/hr is described. The following features will be illustrated and discussed: (1) biological shielding, (2) detector shielding, (3) sample transfer system, (4) remote sample loading and focusing system, (5) laboratory layout, and (6) experimental results.
The Characteristic X-Rays from Boron and Beryllium
Authors: Ehlert R. C. , Mattson R. A.
Published: March 2019

Lead stearate and lead lignocerate multilayer soap-film structures are used to disperse the K emission lines of boron and beryllium respectively. Data are presented showing the dependence of the peak height and half-width on the number of layers in the lignocerate structure. Spectra are presented and compared for the pure element and several compounds of each element. Both electron and X-ray excitation are used. Detection is by a thin-window flow-proportional counter.
The Use of Soft X-Ray Spectroscopy as a Tool for Studying the Surface Region of Metals and Alloys
Authors: Holliday J.E.
Published: March 2019

The present investigation shows that soft x-ray spectroscopy is an effective tool for investigating the surface region of metals and alloys from 10 to 1000 Å. Results are presented where soft x-ray spectroscopy was employed to investigate oxidation of metals and alloys, alloy dissolution, and protective coatings. By using the LII/LIII ratio of iron and titanium, the surface oxide thicknesses of these metals could be obtained, For Fe-Cr alloys there is an increase in the amount of chromium relative to chromium oxide with decreasing chormium content. The oxide surface of steel with a 50 Å metal protective coating was reduced when the protective metal oxide had a heat of formation greater than that of iron oxide. In Cu-30Zn alloys, the first 15 min of dissolution showed an increased copper enrichment in the surface of Cu-30Zn.
Photoelectron Spectrometry: A New Approach to X-Ray Analysis
Authors: Krause Manfred O.
Published: March 2019

Photoelectron spectrometry is shown to be an excellent technique for the analysis of x rays in the ultrasoft and soft x-ray regions. X rays are converted into photoelectrons which are ejected from a suitable atomic level, and the photoelectrons are analyzed with an electron spectrometer. The method is energy dispersive, provides a resolution ranging from 0.1 eV at 20 eV to 1.1 eV at 3 keV, and gives well-defined intensity characteristics throughout the range. The energy range can be extended into the 10 keV decade. Properties of the new technique are discussed, compared with conventional techniques, and exemplified by a series of measurements which include determination of the emission spectra of M x rays of yttrium to rhodium, L x rays of zirconium, and the band structures of molybdenum and holmium.
High-Sensitivity ESCA Instrument
Authors: Davies R. D. , Herglotz H. K. , Lee J. D. , Suchan H. L.
Published: March 2019

A new ESCA (electron spectroscopy for chemical analysis) instrument has been developed to provide high sensitivity and efficient operation for laboratory analysis of composition and chemical bonding in very thin surface layers of solid samples. High sensitivity is achieved by means of the high-intensity, efficient X-ray source described by Davies and Herglotz at the 1968 Denver X-Ray Conference, in combination with the new electron energy analyzer described by Lee at the 1972 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. A sample chamber designed to provide for rapid introduction and replacement of samples has adequate facilities for various sample treatments and conditioning followed immediafely by ESCA analysis of the sample.

Examples of application are presented, demonstrating the sensitivity and resolution achievable with this instrument. Its usefulness in trace surface analysis is shown and some “chemical shifts” measured by the instrument are compared with those obtained by X-ray spectroscopy.
Sensitivity and Detectability Limits for Elemental Analysis by Proton-Induced X-Ray Fluorescence with A 3 Mv Van De Graaff
Authors: Umbarger C. J. , Bearse R. C. , Close D. A. , Malanify J. J.
Published: March 2019

Protons from a 3 MV Van de Graaff have been used to produce characteristic x-rays from 21 elements spanning the periodic table. Absolute Kα and Lα x-ray production cross sections have been determined, allowing one to calculate sensitivities for any given sample, detector geometry, and proton beam parameters. Elemental detectability limits are discussed assuming various backings (e.g., mylar, kapton, etc.) and matrix materials. The large number of available small proton accelerators throughout the United States promises wide applicability of this technique to environmental and biomedical analysis.
The Tetragohal Structure of Collagen
Authors: Shaw E. H. , Laengle T. M. , Coker Howard
Published: March 2019

The normal hexagonal structure of collagen is rearranged to tetragonal by treatraent of rat-tail tendon with two molar tetra-methylammonium chloride. The tetragonal parameters are a = 19.9 and c = 29.6A. Quite regular packing is indicated by the clarity of the X-ray diffractogram. The diffractogram clarity is greatly improved with respect to the collagen treated only with saline solution, and is considerably improved with respect to collagen oriented by cross-linking with aliphatic diols.
A Simple Grazing Incidence X-Ray Lens
Authors: Kaihola Lauri , McGee James F.
Published: March 2019

Currently, making use of the phenomenon of total external reflection of x-rays by matter, lenses are being designed and constructed for use in x-ray telescopes, x-ray microscopes and small angle x-ray scattering cameras. One of the lenses under consideration for a biomedical application is a right-circular cylinder of nominal wall thickness coated with gold. Since the particular biomedical application is not demanding with respect to resolution and image quality in comparison with an x-ray telescope or an x-ray microscope, the imaging properties of the simple right-circular cylinder are satisfactory and the device economical to produce. A detailed study of its properties was undertaken. One of the most stringent requirements on the internal grinding and polishing of such a lens is the roundness of the cylinder. An interferometric method using a laser source enabled the diameter to be determined to one part in 106. Several tests of optical quality vere performed at 6328A in the visible and 8.34A in the X-ray region. A centered stop prevented the direct beam from reaching the screen. A point source of highly coherent 6328A radiation was located on the axis of the cylinder. The divergent beam of light striking the inside walls of the cylinder gives rise to a non-localized Airy-type diffraction pattern. If the surface finish is rough the diffraction pattern will show a star-like pattern at its center. Lack of roundness is indicated by poorly shaped diffraction fringes of low quality. Other optical tests at 6328A in the near and far field regions as well as in the “focal' plane also yield information concerning the roundness and smoothness of the optical element. The previous optical tests when repeated with 8.34A x-rays should give essentially the same general diffraction and interference effects noted with the 6328A radiation. However, most effects are not observable because of the poor resolution of x-ray film, Image forming tests clearly show the presence of barrel and pincushion type distortion.
Reactions in Thin Metal Films Bombarded by the High Intensity Electron Microscope Beam
Authors: Berting F. M. , Lawless K. R.
Published: March 2019

The electron beam of the electron microscope is an excellent source of energy for producing localized observable reactions in thin films.

The normal operating beam of a double condenser lens System focussed for studying a metal film in good thermal contact with its mount gives a calculated temperature rise of about 20° to 50°C. However, by changing these specified conditions, the sample may be heated to temperatures well over 1000°C. Copper and gadolinium--melting points 1083°C and 1312°C respectively--have been melted in the electron microscope beam, as have BeO whiskers--melting point 2530° + 30° C--by the authors and their colleagues.