bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Determination of Thorium in Monazite by Fluorescent X-Ray Spectrometry
Authors: Farquhar M. C. , English M. M. 
Published: March 2019

AbstractA 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

AbstractSmall-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

AbstractA 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

AbstractThe 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

AbstractA 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

AbstractAnalyses 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

AbstractSpectrum 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

AbstractIn 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

AbstractWhile 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

AbstractMost 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

AbstractAn 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

AbstractLead 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

AbstractThe 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

AbstractPhotoelectron 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

AbstractA 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

AbstractProtons 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

AbstractThe 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

AbstractCurrently, 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.
Improved Techniques of Lattice Parameter Measurements Using two X-Ray Beams
Authors: Kishino Seigo 
Published: March 2019

AbstractTwo kinds of improved techniques are described for precise measurement of lattice parameters with an accuracy of 1 ∼7x10-5, in both of which a differenoe of Bragg angles between two X-ray beams such as K α1 and K β1 is measured.In the first technique, which was applied to relatively imperfect crystals such as gallium arsenide, gallium arsenide phosphide, and gallium phosphide, two different diffraction planes were utilized for two radiations such as CuK α1 and CuK β1 in order to reduce the difference of the Bragg angles to the order of several minutes of arc.In the second technique, which was applied to a nearly perfect crystal such as silicon, a double crystal arrangement of parallel setting was used, where lattice parameter of the specimen was relatively measured in comparison with the one of the first crystal which was known beforehand.