bluuebunny/crossref_metadata_2025_split huggingface dataset:
X-Ray Fluorescence Analysis for Sodium, Fluorine, Oxygen, Nitrogen, Carbon, and Boron*
Authors: Henke Burton L. 
Published: March 2019

AbstractOptimized vacuum spectrographic measurement of low-energy fluorescence has been found to yield counting rates and peak-to-background ratios which are enough to permit the extension of fluorescence analysis for elementary chemistry into the light-element range—sodium through boron. This is accomplished with an efficient, demountable ultrasoft X-ray source, with close coupling among source, crystal, and detector, with KAP and multilayered stearate analyzers, and with, optimized flow-propordonal counting. Specific methods for achieving peak-to-background ratios on practical samples containing these light elements are presented. The extension of these methods of light-element analysis with the use of curved long-spaced crystals for X-Ray macroprobe and electron microprobe measurements is discussed. The design and construction of multilayered soap film “crystals” for long-wavelength X-ray analysis is described.
Experimental Dispersing Devices and Detection Systems for Soft X-Rays
Authors: Fischer David W. , Baun William L. 
Published: March 2019

AbstractInstrumentation for soft X-ray research is briefly described. Preliminary results are shown for several dispersing systems which have been found useful in the 10 to 60 Å region. Results from single crystals of Group 1A salts of phthalic acid are discussed and intensity measurements are reported. Other organic single crystals, such as long-chain derivatives of adipic acid are evaluated, along with films of organic compounds prepared by the Blodgètt-Langmuir technique. The efficiencies of the dispersing elements mentioned above are compared with commercial crystals such as mica, gypsum, ADP, and EDDT. Performance of detectors for soft X-rays is shown for fiow-proportional and Geiger counters, a solid state silicon barrier detector, and a windowless resistance strip magnetic electron multiplier. The relative efficiencies of several photocathode materials for the latter are discussed. The design for a scintillation counter sensitive over a wide energy range is discussed and preliminary results using the counter in the region 1-15 Å are shown.
The Accurate Determination of Major Constituents by X-Ray Fluorescent Analysis in the Presence of Large Interelement Effects
Authors: Lucas-Tooth J. , Pyne C. 
Published: March 2019

AbstractFluorescent X-ray spectrometers bave a high inherent reproducibility. It is possible to achieve results, on a routine basis, which have a coefficient of variation of less than 0.1%. Given extremely good chemical standards and the absence of interelemental effects, these readings can be interpreted into percentage concentrations with the same order of accuracy. Results, with this accuracy of analyses of copper in a straight brass will be given. With samples of greater complexity and more elements the interelement effects are large and have to be tackled. A correction method has been established and will be explained in detail.As an example of the method it was decided to tackle the determination of
chromium at high concentrations (7-32 %) in high-alloy steels containing additions in the following ranges: Si, 0.2-2.4%; Al, 0,07-5%; Cu, 1,3-3.6%; W, 0.25-3%; V, 0.1-0.3%; Nb, 0.1-0.3%; Mo, 0.1-4.4%; Ti, 0.05-1%; Mn, 0.35-10%; Ni, 0.2-24%. These very wide alloy specifications were a severe test on the accuracy of the chromium determination & the correction for interelement effects.
Mineralogical Problems in X-Ray Emission Analysis of Sylvite Concentrates
Authors: Bernstein Frank 
Published: March 2019

AbstractMineralogical effects, which relate to the occurrence of an element in different forms of chemical combination, often are a problem to the X-ray analyst since these forms usually differ in X-ray sensitivity. An example of this is cited in connection with the analysis of sylvite concentrates for potassium. An evaluation is made of mineralogical effects and a quantitative relationship between X-ray intensity and mineral form and particle size is derived. If the particle size of a minor constituent is reduced sufficiently the mineralogical effect disappears. Target materials for X-ray sources are found to have only minor effects on relative intensities of different compounds of an element. Finally, it is concluded that the advantages of higher intensities gained through the use of target materials close in atomic number to the material being analyzed far outweigh particle size effects which are shown to be relatively small.
Performance of an Unattended Automated X-Ray Spectrograph
Authors: Davis C. M. , Yanak M. M. 
Published: March 2019

AbstractAmong the advantages of the X-ray spectrograph is the economy realised by minimizing the time of analysis. In the past few years automated features have been developed and applied to reduce analysis time further and to minimize operator errors. These have included a programmed goniometer, an automatic crystal changer, a digitized printer or automatic typewriter, and recently an automatic sample loader coupled with a programmer. With this last attachment, unattended analysis of solid metal samples has been achieved. The precision of data obtained automatically compares favorably with similar data obtained manually.
Evaluation and Application of an Improved Slit Probe for the X-Ray Secondary Emission Spectrometer
Authors: Bertin Eugene P. 
Published: March 2019

AbstractX-ray probe accessories for commercial flat-crystal X-ray secondary emission (fluorescence) spectrometers have consisted of pinhole apertures in the primary or secondary X-ray beam. The smaller the aperture the lower the intensity, and apertures having diameters less than approx. 0.1 mm are of real value only for relatively high concentrations of elements having intense spectral lines.There are two practical methods for increasing the intensity obtained with small apertures. One method is use of curved crystals ; it is applicable to any type of sample. The other method m use of a slit instead of a pinhole. It is limited to samples such as long linear inclusions ; sections of coated surfaces, diffusion couples, and metal-to-metal and metal-to-ceramic interfaces; and other layered structures where composition varies in a direction normal to the layers, but not along any one layer. The slit also has several other disadvantages that do not apply to the pinhole. However, when used with samples of the proper type, the slit has two outstanding advantages : Increased sensitivity and statistical precision are realized by replacing a pinhole of a given diameter with a slit of the same width ; alternatively, improved resolution is realized without loss of intensity by replacing the pinhole with a slit of smaller width. Moreover, the slit can be installed on a commercial X-ray spectrometer quickly and conveniently, and often allows useful X-ray probe work to be done on samples for which pinhole apertures would be inadequate.A slit probe of the type already described by the writer has been improved and evaluated on a General Electric X-ray spectrometer equipped with a curved crystal. The improved accessory has been applied to studies of several metal-tometal and metal-to-ceramic systems. Some of these studies are discussed in detail.
The Use of an X-Ray Fluorescence Semi-Microprobe Attachment in Metallurgy
Authors: Wittig W. J. 
Published: March 2019

AbstractStandard X-ray fluorescence spectrogmphs are capable of measuring elements in areas as small as ⅛-in. diameter, while an electron mitroprobe specialises in areas less than 10 μ. Frequently, a sample of an intermediate size (0.1 mm to 2 mm) requires analysis, so an attachment was designed for Philips Electronics Company equipment. Reasons for its design, sensitivity of the system, and several metallurgical examples showing its versatility are discussed in the report.
Some Measurements of Carbon K Excitation in a New Ultrasoft X-Ray Spectrometer
Authors: Mattson Rodney A. 
Published: March 2019

AbstractAn ultrasoft X-ray spectrograph employing a demountable, water-cooled, cleanable X-ray target will be described. The effects of the spectra emanating from various target materials, operated under several conditions, on the efficiency of excitation of C K radiation will be discussed.
Determination of Rubidium in Cesium Metal by X-Ray Fluorescence Spectroscopy
Authors: Laib Roger D. 
Published: March 2019

AbstractA rapid method for the determination of rubidium in cesium metal by X-ray fluorescence is described. Cesium metal is converted to the chloride, and pellets are pressed with molybdenum trioxide as an internal standard. The rubidium to molybdenum intensity ratio is used to eliminate the effect of small amounts of the other alkali metals. The analytical curve is linear from 0.05 to 15% rubidium, which covers the range of samples normally encountered. Rubidium can be determined with a coefficient of variation of 1.3% in this range. Good agreement was shown with results obtained by flame photometry.
A Camera for Borrmann Stereo X-Ray Topographs
Authors: Young F. W. , Baldwin T. O. , Merlini A. E. , Sherrill F. A. 
Published: March 2019

AbstractA relatively inexpensive camera which was designed for taking Borrmann topographs with standard X-ray diffraction equipment is described. This camera has been used to take stereo pairs of Borrmann topographs by rotating the crystal around an axis normal to the diffraction planes. Topographs have been taken of nearly perfect copper crystals up to 0.2 cm thick using silver, molybdenum, copper, and chromium radiation, and comparisons have been made with topographs obtained with crystal monochromated radiation. Geometrical factors affecting the resolving power of the technique are briefly reviewed. In addition, the resolution inherent in the diffraction phenomenon is analyzed on the basis of the theory of anomalous transmission. Comparisons are made between calculated and observed image widths of a few dislocations.
Lattice Defect Research by Kossel Technique and Deformation Analysis
Authors: Umeno Masataka , Kawabe Hideaki , Shinoda Gunji 
Published: March 2019

AbstractAn electron probe microanalyzer (EPMA) was applied for the deformation analysis of aluminum single crystals. The lattice distortions caused by tensile stresses were observed by Kossel patterns, which are sensitive in their change of shape to lattice distortion. The effects of lattice distortion would appear as splitting, tearing, bending, broadening, disappearance, and shift of Kossel lines. This distortion behavior can be analyzed successfully. The jnhomogeneities and anisotropy appearing on every line were explained by the crystallographic cons (deration of slip mechanisms. The lattice distortions and corresponding changes in Kossel patterns depend on the direction of elongation ; the deformation modes of those crystals which show typical fee behavior in stress-strain curves can be reasonably explained by a fragmentation model. It was also found that there are some portions in Kossel patterns where some specific Kossel lines, i.e., {200} and {111}, are very sensitive to lattice deformation.
Rotational Polymorphism of Methyl-Substituted Ammonium Perchlorates
Authors: Stammler M. , Bruenner R. , Schmidt W. , Orcutt D. 
Published: March 2019

AbstractThe thermal transformations which take place in solid methyl-substituted ammonium perchlorates have been studied using high-temperature X-ray diffraction and differential thermal analysis techniques. In the temperature range from 20°C to their decomposition temperature (above 300°C), ammonium perchlorate and tetramethyl ammonium perchlorate undergo only one enantiomorphic phase transition, namely at 240 and 340°C (with decomposition), respectively. This I—II transition is ascribed to the beginning of the free rotation of the ClO4− ions. The rotation of the cations, however, begins below room temperature. If the symmetry of the cation is lowered by having both methyl groups and hydrogens arranged around the nitrogen (as in monomethyl, dimethyl, and trimethyl ammonium perchlorates), there is an additional enantiomorphic phase transition. This I—II transformation is ascribed to the rotation of the cations which have, in the partially substituted ions, two sets of non-equivalent symmetry axes (different moments of inertia). The temperatures of transformation are discussed in terms of the space requirements for rotation. Symmetries and cell dimensions of some modifications were determined.
A Combined Focusing X-Ray Diffractometer and Nondispersive X-Ray Spectrometer for Lunar and Planetary Analysis
Authors: Das Gupta K. , Schnopper Herbert W. , Metzger Albert E. , Shields Rex A. 
Published: March 2019

AbstractAn instrument is described which is intended to perform a dual purpose (elemental-structural) analysis consistent with the environmental conditions implied by lunar or planetary operation. The dififractometer section is based on a modified Seeman-Bohlin focusing principle in which a sharp-line focus target, a powdered sample, and a movable detector slit all lie on the focusing circle. The convolution of the projections on the focal circle, of a narrow receiving slit on the detector, the line focus target, combined with a high dispersion produce higher resolution and intensity than is common with Bragg focusing diflfractorneters with simitar instrumental parameters. The range of d-spacings covered is from 1 to 7 Å (chromium target). The chemical analysis section of the instrument utilizes the fluorescent X-rays produced in the specimen by the primary beam. A proportional counter and pulse-height anaiyzer accomplish detection and energy discrimination. Resolution is low, but the analysis can distinguish between elements in the range of atomic numbers 11 to 29. Data from a breadboard model is presented. The entire unit, although primarily intended to meet the requirements of space, performs equally well as a routine laboratory analyzer. The horizontal, stationary nature of the specimen holder suggests several specific applications.
Two-Crystal X-Ray Spectrometer Attachment
Authors: Azároff Leonid V. 
Published: March 2019

AbstractA two-crystal spectrometer that makes full use of conventional diffractometet: or spectrometer motions has been constructed so that it can be easily attached to a commercial instrument. The requisite degree of parallelism of the two crystalrotation axes is maintained by keeping both parallel to a single ground surface. Special alignment aids have been constructed to facilitate the rapid alignment of the instrument, which can be operated manually in 1″ intervals or used for automatic scanning in steps of 0.01°. Some guide lines for comparing the relative performance of spectrometers in X-ray absorption spectroscopy are suggested.
Evaluation of Quantitative Electron Microprobe Analyses of Multiphase Microcrystalline Refractory Materials*
Authors: Speidel David H. 
Published: March 2019

AbstractAn appropriate test for homogeneity of composition of standards and of unknown samples is an analysis of variance of the intensity ratios of the components within the grains opposed to the variance between the grains under conditions of constant beam current capacitor change. Replication of analyses is necessary to distinguish inherent instrumental variation from actual chemical inhomogeneities present in the samples. This replication permits an estimate of the imprecision caused by in homogeneities and the statistical variation of X-ray quanta. The total uncertainty of an analysis is the sum of systematic error—primarily reference standard uncertainty—and the imprecision. For multiphase mixtures of microcrystalline refractory oxide material, an uncertainty of ±2% of the amount of oxide component present in a given phase should be considered a good analysis. This value is based on experimental work in the system MgO–FeO–Fe2O3–SiO2.
The Effect of Chemical Combination on Some Soft X-RayKandLEmission Spectra*
Authors: Fischer David W. , Baun William L. 
Published: March 2019

AbstractX-ray spectrochemical analysis is a versatile technique that can be used to determine considerably more than just the elemental composition of a sample. X-ray lines and bands are, in many cases, influenced by the state of chemical combination of the element whose spectrum is being investigated. Significant effects due to changes in bonding are seen in theKandLspectra of the low atomic number elements which fall in the 20 to 90 Å region. Results using primary excitation, a stearate crystal, and a flow proportional counter are shown for theKspectra of boron, carbon, and nitrogen. Chlorine and sulfurLspectra from some simple metal compounds of these elements are also shown.
Chemical Effect on X-Ray Absorption-Edge Fine Structure
Authors: White E. W. , McKinstry H. A. 
Published: March 2019

AbstractExisting theories of X-ray absorption-edge fine structure do not adequately explain details of spectra observed for solids. However, the possibility that X-ray absorption spectra might eventually be used as tools for the characterizatiori of new insulator materials has prompted the study of an extensive selection of simple oxides of known chemistry and structure. The complete K absorption fine structure has been measured for some forty simple oxides of six elements of the fourth period. The L absorption-edge spectra have been measured for metallic lead and several lead oxides. The several isostructurat and polymorphic sets included among these oxides, as well as the Magnéli phases for three of the elements, have made it possible to study the effects of valence, coordination number, electron configuration, and crystal structure. The applicability of current theories of the fine structures are discussed in the light of these findings. An automated single-crystal spectrometer is described.
The Application of a Soft X-Ray Spectrometer to Study the Oxygen and Fluorine Emission Lines from Oxides and Fluorides
Authors: Mattson R. A. , Ehlert R. C. 
Published: March 2019

AbstractResults are shown for O and F K emission lines from several oxide and fluoride compounds. The spectra are examined for both structure and wavelength. Excitation of the spectra is by both electrons and X-rays. The emission spectra from several oxygen- and fluorine-bearing gases and the influence of the composition of the diffracting crystal on the shape of the observed oxygen spectra are also discussed. Curved crystals of potassium acid phthalate and lead stearate, and a thin-window flow proportional counter, are used to obtain the results.
Flash X-Ray Diffraction Systems
Authors: Dantzig Jonathan A. , Green Robert E. 
Published: March 2019

AbstractIn order to develop an optimum system for flash x-ray diffraction, consideration must be given to both optimum x-ray generation and optimum x-ray detection in the correct wavelength regime suitable for diffraction. Historically, most workers have concentrated their efforts in either the generation area or detection area, but not both. As early as 1942, experimental recording of Laue diffraction patterns was reported using a pulsed x-ray generator and exposure times of milliseconds. Recently, successful x-ray diffraction experiments have been reported with exposure times less than 100 nanoseconds.The purpose of the present paper is to trace the development of generation and detection systems for flash x-ray diffraction and to summarize the present state-of-the-art for such systems. A comparative evaluation is presented for flash x-ray diffraction systems using generators which rely on increased electron beam current and those which rely on higher potential difference. Comparison is also made between detection systems incorporating film recording, scintillators fiber-optically coupled to photomultiplier tubes, and image-intensifier systems both lens and fiber-optically coupled to fluorescent screens.A detailed description of the most rapid flash x-ray diffraction system developed to date is given. This system uses a Field Emission Fexitron single channel 300 kilovolt pulsed x-ray generator incorporating an x-ray tube with a beryllium output window. A fluorescent screen converts the x-ray diffraction image into a visible one and this visible image is focused on the first stage photocathode of an image intensifier tube either by direct fiber-optic coupling or by using a coupling lens. The image intensifier tube used is a cascaded three-stage electrostatic focus type with fiber-optic input and output faceplates and inter-stage couplers. Using this system Laue transmission diffraction patterns of single crystals and powder patterns of polycrystalline aggregates have been obtained with exposure times of 30 nanoseconds.
An X-Ray Investigation of Fatigue Behavior of Cold Worked Aluminum
Authors: Gould R. W. , Pittella C. F. 
Published: March 2019

AbstractDouble bending fatigue tests were performed on cold worked 1100 aluminum, with a maximum bending stress varying from 100 to 50% of the yield stress. Variation of residual macrostress from the cold worked state during the fatigue tests was measured by the photographic x-ray diffraction method. A general decrease of this macrostress was observed. Line profile analysis was used to study the change in the mean effective domain size and microstrain. A rate dependence of the increase in the effective domain size with respect to the maximum bending stress was observed. Microhardness and tensile tests were also made on the specimens during the fatigue testing and the results are correlated with the x-ray Parameters.
Contrast of Dislocation Images in X-Ray Transmission Topography
Authors: Authier A. 
Published: March 2019

AbstractA brief review of the different topographic methods is given in order to attempt a classification of the various types of contrast observed. Depending on whether the image is obtained by a reflection or transmission method, is simple or integrated, dynamic, direct, or intermediary, the contrast and image width vary greatly. A detailed analysis is given in the case of transmission section topographs.
Dynamical Theory for Simultaneous X-Ray Diffraction
Authors: Penning P. 
Published: March 2019

AbstractComplete dynamical solutions for three coupled plane-wave components in crystal structures with inversion symmetry have been found. After reviewing briefly the dynamical solutions for wave fields with two coupled plane-wave components, the results for the three-beam case are discussed in qualitative terms. Attention is paid to singular points and lines on the ω-surface, and to the attenuation of the mode-intensity because of absorption. The most surprising result is that in the case one of the reflections is forbidden (Umweganregung) the absorption is reduced in comparison with the adjoining two-beam cases. Experimental data are in reasonable agreement with the theory. Quantitative data are presented for a few three-beam cases of simultaneous diffraction of Cu Kα. radiation in germanium.