bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Micro Segregation on the Observed Intensity in Thin-Film Microanalysis
Authors: Judd G. , Ansell G. S.
Published: March 2019

In the electron-probe microanalysis of thin alloy samples, particularly for areas which contain a high degree of solute segregation as are often obtained in extraction replicas or in electro chemically thinned foils, a correlation between the measured intensity and the sample microstructure has heen difficult to perform. The purpose of this study was to isolate the effect of micro segregation, i.e., segregation with respect to the beam size (∼2 μ) itself, on the characteristic intensity generated by a microvolurne. To accomplish this, a model system consisting of silver-powder particles (∼1 μ diameter) supported on an evaporated carbon film was investigated by using a thin-film microprobe accessory of an electron microscope (Hitachi HXA-1). The silver particles served as analogs to a highly concentrated segregation area, and the carbon film was analogous to the corresponding matrix. The simplicity of this system readily allowed for an analysis of the geometric positioning factor dependence of the generated intensity.

It was observed that the intensity measured for a given particle could vary by as much as 1000% depending only on the relative position of that particle within the electron beam. This variation was derived to be due to both the distribution of electrons within the beam and the amount of mass occupied by the particle at each distance from the beam center. A computer program was developed to perform the necessary calculation to predict the relative intensity as a function of position within the beam. These calculated intensities were found to compare favorably with the experimental measurements.
Computerized Multi Phase X-Ray Powder-Diffraction Identification System
Authors: Johnson G. G. , Vand V.
Published: March 2019

A computer search system utilising the Powder Diffraction File compiled by the Joint Committee on Powder Diffraction Standards, originally developed for an IBM 7074 in FORTRAN II and reported at the Pittsburgh (1966) conference, has beer. revised and extended to run on IBM 360/50. The system is now written in FORTRAN IV. This search system, which uses all the lines of the reference patterns, has successfully identified up to six standard reference patterns from a multiphase unknown X-ray diffraction pattern in less than 2 min running time. No chemical information is necessary for the system to run. In the revised program, the chemical composition of the patterns is now available from the magnetic tapes in immediate conjunction with the printout of the “most likely” components of the mixture. However, this chemical information is not used by the program itself in the search procedure since, if the unknown pattern is absent from the file, it is helpful to know those compounds which are isostructural with the unknown pattern. With the immediate use of chemical information, these patterns would be eliminated. An estimation of the relative concentration of each of the components, based on absolute intensities, is also calculated by the program. This identification system has been run on experimental data both of the Guinier type and of a less reliable type, with the present Powder Diffraction File on the search tape. Although the number of false matches was increased with the poorer quality of input data, the programs yielded excellent results for both single- and multiple-phase patterns even with poor data and the absence of any chemical information. A series of results from the Materials Research Laboratory of The Pennsylvania State University, illustrating the system in operation with increasingly difficult mixtures, will be given. With such a system in operation at such a small cost, the diffractionist can concentrate on the results and meaning of the identification rather than on the method of identification itself.
Standard Data for the Identification of Phases By X-Ray Diffraction
Authors: McMurdie Howard F.
Published: March 2019

The identification of crystalline phases by x-ray diffraction, either by powder or single crystal techniques requires a dependable body of reference data. It is not only necessary to have data on each phase which are accurate and complete, it also is desirable to have data on as wide a range of compounds as possible, and to have the data organized in such a manner as to be readily usable. The outstanding compilations which approach these goals are the Powder Diffraction File and Crystal Data.

The Powder Diffraction File, published by the Joint Committee on Powder Diffraction Standards has data covering about 22,500 phases, both organic and inorganic. These data are of various degrees of accuracy as is indicated by symbols. The File is continuously being improved by the addition of evaluated data from the general literature and by data produced by supporting projects, the principal one being the Joint Committee Associateship at the National Bureau of Standards.

To be noted in the File with a star, and to be truly considered standard data a powder pattern must be complete in the sense of including all reflections above the minimum “d” spacing covered, both weak lines and those with large “d” spacings. Since the best test of a pattern is its own internal consistency, the reflections must all have hkl's assigned and must show a good agreement between the spacings observed and those calculated from a refined cell, and they must be consistent with the known space group. This agreement can be best obtained by the use of an internal standard and a computer program. The intensities should be measured by a method which minimizes the effect of crystal orientation.

The PDF is provided with search procedure manuals arranged on a scheme of the strongest lines to help in locating data matching that from an unknovm. A computer program for rapid searching is available. A recent development is the inclusion of a “reference intensity” to aid in estimating the quantitative analysis of mixtures.

Crystal Data is a compilation now in the third edition made at the National Bureau of Standards and published by the Joint Committee on Powder Diffraction Standards. It contains data on the unit cell parameters of over 24,000 phases. These data are arranged by crystal system and axial ratios to simplify identification of phases from unit cell data obtained from Single crystal cameras.

Both of these large compilations are also important reference sources for crystallographic information giving structural information and literature references.
Role of Diffractometer Geometry in the Standardization of Polycrystalline Data
Authors: Parrish William
Published: March 2019

This paper reviews the factors in diffractometer geometry most likely to cause large errors in intensity measurements due to imperfect specimen preparation, particularly preferred orientation. It is recommended the same specimen be transferred to two or more diffractometer geometries in which the specimen has different orientations to obtain sets of complementary data. Three geometries are illustrated: θ-2θ scanning with reflection and transmission specimens, and Seeman-Bohlin with reflection specimen.
Can Regression Equations be Optimized By Finagling X-Ray Intensities?
Authors: Fatemi M. , Birks L. S.
Published: March 2019

The application of the null-determinant technique to eliminate the inconsistency of x-ray empirical equations is investigated. Experiments with a series of stainless steel standards show that, in general, calculated compositions obtained by the null-determinant technique agree more closely with chemical analysis than do those obtained by simple averaging. Since it is usually errors in measured intensities which lead to inconsistent estimates of concentrations, the advantages of the null-determinant technique in adjusting the intensities become evident.
An X-Ray Amorphous Scattering Investigation of the Corrosion of a Potassium Silicate Glass K2O-3Si02
Authors: Gould R. W. , Hill M. S.
Published: March 2019

Structural modifications occurring in corroded potassium silicate glasses were studied using x-ray amorphous scattering techniques. Pair function distribution curves are compared and the differential method is used to follow the structural changes. The structure appears to approach that of vitreous silica after long leaching times.
Qualitative Analysis of the Kossel Back Reflection Pattern from Selected Semiconductors
Authors: Fitzpatrick Robert L.
Published: March 2019

The value of the divergent beam method as a powerful tool for investigating crystal perfection over rather wide limits has been known since the analytical work of K, Lonsdale. This method has been treated experimentally and theoretically by numerous authors and was popularized by Sigmund Weissmann. Although not nearly as useful as the reflection and transmission topographic techniques of Berg-Barrett and Lang for crystal characterization, it is potentially very useful for three dimensional quantitative strain analysis. The “technique phase” as Harvey Yakowitz remarked, is essentially over; however, refinements and optical improvements are certain to evolve if quantitative measurements are to become useful. Very short exposures and the non-destructive nature of the reflection divergent beara - Kossei method is a useful survey tool that has gained limited acceptance.

Presently, the reflection mode is useful in the qualitative survey of numerous semiconductor materials and processes, some of which have been considered from time to time by various authors. A range of crystal perfection, as well as some surface modifications, are surveyed. Kossel reflection pattern artifacts and irregularities are discussed.
A Spherically Bent Crystal X-Ray Specteometer with Variable Curvature
Authors: Parker Donald L.
Published: March 2019

The design and performance of a spherically bent crystal x-ray spectrometer with variable curvature are given. A thin crystal with the diffracting planes parallel to the face is mounted on a vacuum chuck consisting of an O-ring in a brass mounting. A controlled partial vacuum is applied behind the crystal to cause spherical deformation of the lattice. Thus, rays from a point source on the focusing circle are diffracted to a line image also on the focusing circle. The differential pressure is automatically varied such that the source-to-crystal and crystal-to-image distances are equal and constant for all Bragg angles and hence the simple θ-2θ motion of a one flat crystal spectrometer is used.

The data are accumulated by a scanning proportional counter tube placed behind a vertical slit (perpendicular to the scattering plane) located at the image line. The fixed chord length is 22 cm and the instrument is designed to scan from zero up to 120° 2θ. Crystals are easily interchanged and the automatic vacuum regulator has sufficient flexibility to allow tailoring the spherical bending to crystals of materials of various thicknesses. The resolution is easily adjusted by either the size of the x-ray source or the width of the detector slit. The performance of the spectrometer has been evaluated by characteristic x-rays produced by various samples placed in a demountable x-ray tube. The main advantages of this three-dimensional focusing instrument are the very high signal-to-noise ratio and the very low levels of x-ray flux required.
Measurement of the X-Ray Sensitivity of Silicon Diodes in the Energy Region 1.8 to 5.0 Kev
Authors: Hohlfelder Jacque J.
Published: March 2019

Planar, Silicon diodes have been calibrated in the energy region 1.8 to 5.0 keV using low-energy, continuous-mode x rays. The spectral energy distribution of each of six x-ray spectra used in the calibration was measured using a non-dispersive Si(Li) x-ray spectrometer. X-ray spectral fluxes were measured using a xenon-filled, parallel-plate ionization chamber. A chopper-wheel and phase-sensitive detector combination was used to enhance the signal- to-noise of the silicon diode signals in order to measure the x-ray induced diode currents, ∼10-10) A., in the presence of diode dark currents of order, 10-5 A. Measured data were consistent with diode silicon dead layers of from 0.3 to 0.4 μm. Average agreement to within five percent was found between measured diode sensitivities and calculated diode sensitivities. The measured diode x-ray sensitivities are compared with independently-measured diode x-ray sensitivities of similar diodes.
Development of the High Performance 'Solfa' On-Line Analyser to Measure Total Sulphur in Petroleum Distillates and Residual Fuels Using Non-Dispersive X-Ray Fluorescence
Authors: Gamage C.F. , Topham W.H.
Published: March 2019

In any petroleum product, a high sulphur content is considered undesirable. Sulphur in diesel fuels is claimed to aggravate problems of wear and deposit. With residual oils used in some metallurgical operations, the sulphur combustion products can have an adverse effect on the metal. In combustion equipment, the oxides of sulphur together with water vapour can lead to undesirable acid condensatlon on cool metal surfaces.

The more general problem is air pollution. Local and national legislation present the oil industry with a continuing demand for fuels of lower and lower sulphur content. Best use must therefore be made of crude oils of inherently low sulphur content. Desulphurising processes are comnonly used for distillates and are available for residual products. Such processes however tend to add significantly to produetion costs.
Changes in the Bragg-Williams Parameter with Deformation in Ordered Au4V
Authors: LeFevre B. G. , Starke E. A.
Published: March 2019

The intermetallic compound Au4V is known to be ferromagnetic at temperatures below 43°K. Its ferromagnetism, which has been attributed to long range order, can he destroyed by cold deformation. The present study was undertaken to determine how the Bragg and Williams long-range-order parameter of the fully-ordered alloy varied as a function of deformation by cold rolling. Because of complexities in the diffraction spectrum it was not possible to determine 5 by a simple ratio of integrated intensities as is frequently done in other ordered systems, A treatment was developed to handle these difficulties using a modification of a method developed by Giamei and Freise for determining volume fractions of mixed phases. These results are correlated with magnetic measurements made by Chin and coworkers at Bell Laboratories.
Deformation Textures of Ordered and Disordered Cu3Au*
Authors: Starke E. A. , Ogle J. C. , Sparks C. J.
Published: March 2019

The development of deformation textures of both initially disordered and ordered Cu3Au has been studied and discussed in terms of the stacking fault energies and twinning probabilities. No differences in the deforir.ation textures of the ordered and disordered materials were detected at deformations up to 40% reduction. However, at reductions of approximately 42% a marked difference was observed. This difference is attributed both to the degree of order and to the stacking fault energy of the ordered sample being conducive to deformation twinning at this stage of the rolling schedule. For samples which were reordered below the racrystallization temperature at intermediate stages of deformation (every 10% in total reduction) no differences between the ordered and initially disordered samples were observed up to 90% total reduction in thickness.
Solution Absorptiometry with Beta Excited Sources by Means of Balanced Filters
Authors: Toothacker William S. , Preuss Luther E.
Published: March 2019

The use of beta excited x-ray sources in solution absorptiometry has been reported upon by this laboratory. These sources produce characteristic K x-ray lines superimposed upon a bremsstrahlung continuum. The work previously reported made use of the entire beta excited spectrum. The resulting plots of In (Io/I) versus concentration of solute were not straight lines, (I0is the intensity of the x-rays after passing through the solvent, and I is the intensity after passing through both the solvent and solute), but curved downward, as is characteristic of polychromatic sources due to preferential absorption of the low energy photons. These sources have a bremsstrahlung end-point equal to the beta energy E-max. This continuum energy usually is relatively high, resulting in a high mean x-ray energy for the polychromatic beam. This is not a desirable condition. Ideal sources for absorptiometry would be monochromatic in nature with an overall energy range covering the values for the elements. The use of a monochromatic source has two advantages for solution absorptiometry. First, the sensitivity is much greater since the K peak is of lower energy than the bremsstrahlung continuum. Secondly, the plot of In (Io/I) versus solute concentration is a straight line since a fixed value of the mass absorption coefficient can be assigned to this fixed energy, thus simplifying calibration. To use only the monochromatic K energy from these beta excited sources, we have applied the method of balanced filters. These monochromatic K x-rays, with the remainder of the continuum filtered out, have been employed in solution absorptiometry. The resulting plots of In (Io/I) versus solute concentration are straight lines with very good sensitivity. Using this technique, a very wide range of monochromatic energies are available for use in solution absorptiometry.
Simple Two Crystal Spectrometer and its Application to X-Ray Spectrochemical Analysis
Authors: Gohshi Y.
Published: March 2019

A simple two-crystal spectrometer was constructed, making use of a commercial one-crystal spectrometer. A detector attached to a 2θ-arm has been replaced by a second crystal. After adjustment, the second crystal is fixed to the 2θ-arm. The detector is placed at an appropriate position apart from the 2θ-arm. The spectrometer is operated as if it were a one-crystal spectrometer. The dispersion of the spectrometer in this mode of operation is the sum of those of the first and second crystals. Ge(220) crystals gave the best resolution which was about 3-3 eV fwhm for Cu Kα1. The strongest Intensity was observed using etched LIF crystals. The intensity was about 1/4 of that of a one-crystal spectrometer and the resolution was about 9.5 eV fwhm for Cu Kα1. The spectrometer was applied to the determination of hafnium in zirconium and sircaloy. The Zr Kα 2nd order line, which coincides with the Hf Lα1 line, was completely eliminated by successive reflections by Ge(111) crystals owing to the extinction rule and the high resolving power. The detection limit was about 7 ppm of hafnium. Another example is the separation of the As Kα2 line from the Pb Lα1 line. Arsenic in low alloy steel was determined without the correction for the well known Interference of lead. The very common interference of Cr Kβ on Mn Kα was also eliminated completely by this spectrometer. Though the spectrometer is not very suitable for a wide wavelength range spectroscopic measurement, owing to its narrow window region (about ±1°), the chemical effects on Kg spectra of sulfur in various compounds were investigated. Fine structures were found In the sulfur Kβ spectra of several thiocyanates and elemental sulfur. To observe long wavelength region spectra, the X-ray path of the spectrometer was modified to a hybrid path (vacuum and helium).
Analysis of Magnesium Brines by Energy Dispersive XRF
Authors: Reilly John F. , Langenfeld Debbie J.
Published: March 2019

The analysis of magnesium brines can be performed by atomic absorption and classical wet chemical techniques. These methods are subject to dilution errors and are time consuming. This paper describes a method using energy dispersive x-ray fluorescence to determine magnesium, sulfur, chlorine, potassium and calcium in concentrated magnesium brines.
In Vivo X-Ray Fluorescence Analysis for Medical Diagnosis
Authors: Ahlgren L. , Grönberg T. , Mattsson S.
Published: March 2019

Occupational exposure to lead is common in many industrial applications and hence it is of considerable medical interest to control the body-burden of lead in living man. More than 90 % of the lead in the body is concentrated in bone and hence in vivo measurements of the lead in the skeleton should give the most satisfactory way for estimating the body-burden. The routine method used today for checking on lead contamination is that of measurements on blood samples. However, since the concentration of lead in the blood is a sensitive function of the actual exposure conditions, this method provides only a poor indication of the total body-burden and the integrated lead exposure.
X-Ray Fluorescence Analysis at Room Temperature with an Energy Dispersive Mercuric Iodide Spectrometer
Authors: Singh M. , Dabrowski A.J. , Huth G.C. , Iwanczyk J.S. , Clark B.C. , Baird A.K.
Published: March 2019

We have previously reported on the uniqueness and potential of room-temperature spectrometry of low-energy x-rays with a mercuric iodide (HgI2) detector (1,2,3). In this paper we emphasize the use of HgI2 detectors for x-ray fluorescence (XRF) analysis.

Because no vacuum plumbing or cryogenic cooling is required, the design of a mercuric iodide room-temperature x-ray spectrometer is extremely simple. Our present design consists of coupling a detector directly to the first-stage FET in a modified Tennelec 161 D preamplifier and making the configuration “light-tight”. Aside from providing a suitable entrance window, there are no other requirements for routine spectroscopy.
A Second Derivative Algorithm for Identification of Peaks in Powder Diffraction Patterns
Authors: Schreiner W. N. , Jenkins Ron
Published: March 2019

Modern (>1950) data analysis techniques are commonly applied in many scientific fields but their careful application in other fields, including X-Ray diffraction, has been notably lacking or generally confined to the environment of university research. Perhaps this lack of widespread application in XRD can be blamed on the absence of sophisticated computer controlled instrumentation, and, if this is so, the situation should change rapidly, since today's automated diffractometers are driven by very powerful minicomputers with large firm disks and sophisticated operating systems. In such an environment it is entirely practical to implement, on-line, state-of- the-art data analysis techniques, and in this paper we present one such example.
Advances in the Computer Indexing of Powder Patterns
Authors: Smith Gordon S.
Published: March 2019

Indexing of powder-diffraction patterns by computer techniques has advanced to the state that it is now often possible to determine unit-cell dimensions and crystal system for an unknown material solely from its powder-diffraction data. This indexing is fully automated, proceeding directly from positions of observed diffraction lines as input, with decision-making steps being made by a computer. Ease of indexing depends on quality of data (accuracy and completeness), volume of the unit cell, and symmetry of the crystal system. In general, a powder pattern of a triclinic compound with a large unit cell requires a more accurate and complete data-set for successful indexing than does a cubic material having a small unit cell. Fortunately, data from a well-aligned diffractometer or Guinier camera ordinarily suffices for computer indexing. Because of systematic errors in the low-lying diffraction lines, data from the Debye-Scherrer technique usually are not adequate for computer indexing (except for the simpler cases). A brief review of the strategies/algorithms of some of the computer indexing codes now available is given. Criteria for assessing the reliability of a particular computer- assisted indexing are discussed. Finally, attention is directed toward future developments such as by automating the collection of powder- diffraction data, analyzing data by computer data processing, and increasing the speed and reliability of computer indexing.
A Position-Sensitive Proportinal Counter for Residual Stress Measurement by means of Microbeam X-Rays
Authors: Yoshioka Yasuo , Hasegawa Kert-ichi , Mochiki Koh-ichi
Published: March 2019

A position-sensitive proportional counter (PSPC) with high counting efficiency has been made for stress analysis with low intensity X-rays such as microbeam X-rays.

This PSPC system has made it possible to measure the residual stress in a small region such as a fatigue crack tip in very short time compared with the measurement by standard diffractometer or film methods.
Instrumentation for X-Ray Diagnostics of Plasmas*
Authors: Violet C. E.
Published: March 2019

Measurements of x-rays emitted by hot plasmas provide a powerful diagnostic method of determining important plasma parameters and suggest certain types of plasmas as possibly useful x-ray sources. Instrumentation to accomplish these measurements for various types of plasmas are reviewed. State-of-the-art x-ray spectrometers, calorimeters, and source-imaging devices, designed especially for plasmas generated by focused, nanosecond laser pulses are described. Possibilities of time-resolved measurements on such short-lived plasmas are discussed.
Amplification of Soft X-Rays in a Picosecond Laser-Produced Plasma
Authors: Lacour B. , Maillet M. , Michon M. , Tuilier M. H.
Published: March 2019

We investigate the possibilities of amplification of soft x rays in a low Z plasma produced by a picosecond laser. Inversion of population could take place between metastable and fundamental state of lithium-like ions.
X-Ray Pulse Calorimetry of Laser-Produced Plasmas*
Authors: Violet C. E. , Petruzzi J. , McQuaid J. H. , Boster T. A. , Richards L. M. , Mead S. W. , Saroyan R. A. , Swain J. E.
Published: March 2019

The x-ray energy emitted from laser-produced plasmas has been measured under various experimental conditions. Two Nd-glass lasers were used in separate experiments to focus pulsed laser light on planar targets. X-ray fluences were measured with newly developed silicon detector calorimeters. Results for various experimental conditions are reported in terms of the efficiency with which the laser light was converted to x-ray energy by plasma production.
X-Ray Fluorescence Analysis with Transmission Target Tubes
Authors: Zulliger H. R. , Stewart J. E.
Published: March 2019

Todays demand for rapid trace element analysis in pollution control and resource materials has led to the development of a completely automatic, very sensitive and stable Si(Li) X-ray analyzer. The key element, a transmission target tube, which has inherently a very clean monochromatic X-ray output, has been studied in view of efficiency, sensitivity and stability. The transmission target tube requires different operating criteria than conventional X-ray tubes. An analysis was made to “explain” these differences using fundamental X-ray physics. Studies included various experiments directly applied to practical problems in analysis of pollutants and mineral resource materials.
Application of Proton Induced X-Ray Emission Analysis to the St. Louis Regional Air Pollution Study
Authors: Akselsson R. , Orsini C. , Meinert D. L. , Johansson T. B. , Van Grieken R. E. , Kaufmann H. C. , Chapman K. R. , Nelson J. W. , Winchester J. W.
Published: March 2019

The St. Louis aerosol was sampled during the period 16-22 August 1973 simultaneously at two locations using cascade impactors for sequential 12-hour samples. The six particle size fractions of each sampling were individually analyzed using PIXE for elements from S to Br and beyond and for heavy elements including Pb which permitted time variations of concentrations and particle size distributions to be followed and related to meteorological changes during the sampling period. In addition, the data were compared with average levels of the elements in coastal north Florida and maritime Bermuda as well as at a third St. Louis site. From this it appeared that some of the concentrations in St. Louis were at natural levels whereas others appeared to be higher and linked to air pollution sources. These relationships and others in this study may lead to criteria for distinguishing between pollutants and natural background in urban aerosols.
Analysis and Interpretation of Diffraction Data from Amorphous Materials
Authors: Konnert J. H. , D'Antonio P. , Karle J.
Published: March 2019

Amorphous materials give rise to rather diffuse diffraction patterns. In contrast to diffraction patterns from polycrystalline materials which are characterized by a large number of sharp diffraction rings, patterns from amorphous materials are composed of relatively few broadened features. Such a diffuse pattern, however, contains much structural information in the form of an interatomic distance distribution that may be computed directly from the measured diffraction pattern. This radial distribution function (RDF) provides information concerning bonded distances, the types of atomic groupings and the extent of ordering in the sample. Special care, however, must be taken during the analysis to avoid introducing spurious details into the RDF that may be confused with, or mask real structural features. Such false detail may arise both from data collection and data reduction procedures. The availability of modern computers has greatly facilitated the calculation of accurate RDF's by readily permitting the introduction of physical criteria into the data reduction procedure that must be satisfied by the RDF.
A Versatile X-Ray Stress Analyzer Using a Position Sensitive Detector
Authors: Yoshioka Yasuo , Hasegawa Ken-ichi , Mochiki Koh-ichi
Published: March 2019

Instrumentation for X-ray stress analysis has been advanced rapidly in the last few years. Especially, the time required for data accumulation has been remarkably reduced without motion of the detector by using a new X-ray detector called a position sensitive detector (PSD). Applications of PSD to the field of X-ray stress analysis were carried out by James and Cohen, Ruud and Barrett, and the authors. In our laboratory, several position sensitive proportional counters (PSPCs) were designed and manufactured for residual stress measurements. Results show that the PSPC method is a powerful alternative to the conventional counter method or the film method.

This paper reports a design of a versatile PSPC X-ray stress analyzer for use in industry and the laboratory.
X-Ray Diffraction Evaluation of Adhesive Bonds and Stress Measurement With Diffracting Paint
Authors: Barrett Charles S. , Predecki Paul
Published: March 2019

X-ray diffraction is found effective in disclosing the distribution of stresses over the surface of adhesively bonded lap joints when loads well below the yield point are applied. When a pair of 6061-T6 aluminum strips 1/16” or 1/32” thick and 3/4” wide is adhesively bonded in a single lap joint and loaded in tension, maps giving the distribution of the X-ray-measured stresses show the limits of the bonded area with an accuracy about equal to the width (1 mm) cf the irradiated area along the specimen. Attendant bending stresses resulting from the loading are also registered. Stress values can be obtained from the observed diffraction angles by calibration with tensile tests of a single unbonded strip. Similar results are obtained for graphite/epoxy laminates adhesively bonded in a single lap joint to aluminum when diffraction is from the aluminum, but a lower accuracy is obtained when diffraction is from the filled composite.

Another X-ray method was developed for measuring applied (not pre-existing residual) stresses, and for mapping their distribution around a joint. A thin layer of epoxy paint containing a diffracting filler (say aluminum or silver powder) is applied to a specimen and cured. Diffraction from this paint yields shifts in diffraction angle approximately proportional to the magnitude of applied stresses. The limits of the bonded area in single lap joints under load are disclosed. Both methods appear, therefore, to be practicable for mapping the areas that are properly bonded, and presumably also for non-destructive evaluation of bond defects.
The Characterization of Alpha and Intermediate Aluminum Oxide Mixtures by Semi-Automated XRD
Authors: Burleson John R.
Published: March 2019

Intermediate aluminum oxides (aluminas) have broad X-ray diffraction (XRD) peaks. Many of the phases have similar XRD patterns with overlapping of major peaks. To characterize a multi-component alumina mixture several regions of multiple overlapping peaks are examined. Each region is integrated to a single sum without regard for individual peaks. The integrated regions are applied to various ratio functions obtained from single component standards. By using an iterative technique, the functions converge to yield weight fractions for up to six alumina phases.
Use of Compton Scattering in X-Ray Fluorescence for Determination of Ash in Indian Coal
Authors: Pandey H. D. , Haque R. , Ramaswamy V.
Published: March 2019

X-ray fluorescence method using Compton scattering for the determination of ash in coal has been systematically studied for application to Indian Coal. Fluorescent intensities from major constituents such as Al2O3, SiO2, TiO2, Fe2O3, CaO and their various combinations were used in conjunction with the reciprocal of the Cr Kα Compton intensity in a regression equation. Varying degrees of correlations were obtained between the values of ash determined by conventional methods and those calculated from X-ray data. It is found that Ti fluorescent intensity plays a major role in the regression equation and its contribution cannot be ignored if the Cr X-ray tube is used.
Improving the Detection Limit in Wavelength Dispersive XRF
Authors: Sipilä Heikki
Published: March 2019

The origin of the background under the signal in the wavelength dispersive XRF has been investigated. The methods of minimizing the background are presented. The bremsstrahlung is eliminated by using a primary filter in front of the X-ray tube. The background generated by the X-ray detector is decreased with a pulse risetime and a pulse interval analyzer. For example, in the fixed uranium spectrometer channel a 500-fold improvement of the peak-to-background ratio was achieved.
A Scheme for Fully Quantitative Energy Dispersive Microprobe Analysis
Authors: Smith D.G.W. , Gold C.M.
Published: March 2019

A procedure and program are described for rapid, economical and simple production of fully quantitative, multi-element analyses from energy dispersive microprobe data. Methods are outlined for background shaping and scaling, comprehensive overlap correction, and adjustment for instrumental drift. Program facilities include the output of all coefficients required, built-in standard data, the option to use default standards when no working standards have been measured, and the ability to respecify standards during data processing.
Analysis of Portland Cement, Clinker, Raw Mix, and Associated Ceramic Materials Using an Energy Dispersive X-Ray Fluorescence Analyzer With Interelement Corrections
Authors: Cooper J. A. , Wheeler B. D. , Bartell D. M. , Gedcke D. A.
Published: March 2019

A rapid multielement analysis procedure for cement and ceramic type materials has been developed which uses pelletized powders and an exponential correction to the observed x-ray intensities. Only the more significant interactions are considered in an iterative process requiring a minimum of standards. The interaction coefficients are determined by a nonlinear multiple least squares fit of the standards. Average deviations obtained for the analysis of light elements in cement ranged from a low of 0.006% for K2O to a high of 0.13% absolute for SiO2.
Quantitative Analysis of Selected Minor and Trace Elements Through Use of a Computerized Automatic X-Ray Spectrograph
Authors: Fabbi B. P. , Elsheimer H. N. , Espos L. F.
Published: March 2019

Upgrading a manual X-ray spectrograph, interfacing with an 8K computer, and employment of interelement correction programs have resulted in a several-fold increase in productivity for routine quantitative analysis and an accompanying decrease in operator bias both in measurement procedures and in calculations. Factors such as dead time and self-absorption also are now computer corrected, resulting in improved accuracy. All conditions of analysis except for the X-ray tube voltage are controlled by the computer, which enhances precision of analysis. Elemental intensities are corrected for matrix effects, and from these the percent concentrations are calculated and printed via teletype.

Interelement correction programs utilizing multiple linear regression are employed for the determination of the following minor and trace elements; K, S, Rb, Sr, Y, and Zr in silicate rocks, and Ba, As, Sb, and Zn in both silicate and carbonate rock samples. The last named elements use the same regression curves for both rock types. All these elements are determined in concentrations generally ranging from 0.0025% to 4.00%, The sensitivities obtainable range from 0.0001% for barium to 0.001% for antimony. The accuracy, as measured by the
percent relative error for a variety of silicate and carbonate rocks,
is on the order of 1-7%. The exception is yttrium (13.8%).
Application of a Low Energy X-Ray Spectrometer to Analyses of Suspended Air Particulate Matter
Authors: Giauque R. D. , Garrett R. B. , Goda L. Y. , Jaklevic J. M. , Malone D. F.
Published: March 2019

A semiconductor detector x-ray spectrometer has been constructed for the analysis of elements in air particulate specimens. The excitation radiation is provided, either directly or indirectly, using a low power (40 watts) Ag anode x-ray tube. Less than 100 ng for most of the elements in the range Mg → Zr, Pb are easily detected within two 1-minute counting intervals. A calibration technique for light element analysis and an experimental method which compensates for particle size effects will be discussed.
REX: A Computer Program for Pixe Spectrum Resolution of Aerosols
Authors: Kaufmann Henry C. , Roland Akselsson K. , Courtney William J.
Published: March 2019

REX is a Fortran program for analysis of spectra obtained in PIXE analysis. The underlying model is still under development; however, one year of experience has demonstrated REX's capability to be a fast reliable tool. The modeling of the different components and effects of the physical model is briefly discussed. Evidence is shown that secondary effects mostly due to Compton-scattering in and around the detector are important factors. In order to assure that heavy elements are recorded with sufficient sensitivity during short bombardment times, low energy X-rays are suppressed but not completely absorbed by use of a Mylar absorber with a hole. Such an absorber sometimes introduces severe problems for other techniques of spectrum analysis. However, to REX there is only the job to find the transmission curve of the absorber.
X-Ray Techniques for Aerosol Sulfur Baseline Asessment Along an Urban Freeway
Authors: Akselsson K. R. , Hardy K.A. , Desaedeleer G.G. , Winchester J.W. , Berg W.W. , Vander Wood T.B. , Nelson J.W.
Published: March 2019

Atmospheric aerosol particles have been sampled near a Los Angeles freeway and analyzed by proton-induced X-ray emission, PIXE, as a sulfur baseline study in September 1974 before 1975-model auto mobiles, equipped with catalytic emission control devices, appeared in large numbers. The sampling plan was optimized a c cording to the requirements of X-ray analysis techniques, fluctuations in air flow across the freeway, and the time and particlesise resolution of the aerosol sampling equipment. During five selected two-hour intervals with cross wind conditions, particles were collected as a function of size by six cascade impactorsope rating simultaneously on three towers at 2 and 7 meters above road level 35 meters upwind and 35 meters downwind of the traffic lanes. Particles as a function of time were sampled continuously, for the 100-hour duration of the experiment, from the three 7-meter heights using time series streaker filter samplers with two-hour time resolution. Precise analyses of S, Cl, K, Ca, Fe, Br, and. Pb established relationships which permit estimates to be made of future increases in particulate sulfur as a consequence of increased sulfate emissions from catalytic automobiles.
Development of a Particulate Reference Sample on Membrane Filters for the Standardization of X-Ray Fluorescence Spectrometers
Authors: Pella P.A. , Kuehner E.C. , Cassatt W.A.
Published: March 2019

Particulate reference samples have been prepared for the standardization of x-ray fluorescence spectrometers used in the analysis of air particulate matter. Uniform layers of reground orchard leaves of known composition, i.e., National Bureau of Standards Standard Reference Material SRM 1571, were deposited on membrane filters and coated with a thin polymer film for protection against abrasion and moisture. These samples have been prepared with areal densities of 0.1 to 5.0 mg/cm2.
X-Ray Fluorescence Spectroscopy as a Tool for Fish Stock Discrimination
Authors: Kieser R. , Mulligan T. J.
Published: March 2019

X-ray fluorescence spectroscopy is being used to measure the elemental composition of fish tissues. The elemental data are then subjected to pattern recognition procedures in an attempt to discriminate fish stocks.
X-Ray Diagnostics in the Laser-Initiated Fusion Program
Authors: Godwin R. P.
Published: March 2019

The high-density and high-temperature plasma conditions required for successful laser-initiated fusion make x-ray diagnostics a valuable tool in this exciting field. Measurements of the hard x-ray bremsstrahlung continuum emitted from laser targets provide insight into the complex laser-plasma coupling physics and the subsequent electronic energy transport. X-ray techniques are important in the selection and assay of microballoon targets for current compression experiments. X-ray imaging experiments and diffraction spectroscopy of highly stripped atoms can provide information about the symmetry, density and temperature of laser targets. Extremely high temporal and spatial resolution may be required for definitive diagnostic information on compressed targets. While laser-produced plasmas are interesting as possible intense x-ray sources and as a possible means of achieving x-ray lasing, those topics are outside the scope of this review.
Surface Characterization by X-Ray Techniques
Authors: Park Robert L.
Published: March 2019

The filled states in the surface region of a solid can be probed by monochromatic x-rays. The spectral distribution of photoelectrons near the high kinetic energy limit is related to the density of valence band states. Complementary information regarding the unoccupied states is obtained from the spectral distribution of bremsstrahlung, emitted bv radiative capture of monoenergetic electrons, near the short wavelength limit. In soft x-ray appearance potential spectroscopy, the near-threshold excitation probability of a core level is a measure of the local density of unfilled states associated with a particular element. In each case the sensitivity to the surface results from the short mean free path for inelastic scattering of electrons. Unfortunatelv this has severe consequences for the interpretation of line shapes.
Photon Standards for Energy and Efficiency Calibration of X-Ray Fluorescence Analyzers
Authors: Notea A. , Segal Y.
Published: March 2019

A set composed of barium-133 (7.8y), europium-152g (13.4y), bismuth-207 (30y) and americium-241 (458y), is recommended for energy and efficiency calibration of x-ray spectrometers. It is shown that the set offers over 30 energy lines in the range below 100 keV. The absolute efficiency calibration of Ge(Li) and Si(Li) detectors is demonstrated. The calibrated Ge(Li) was used for the measurement of fluorescence excitation yield from lead excited by various γ sources.
Quantitative Determimatioh of Sulfur, Chlorine, Potassium, Calcium, Scandium and Titanium in Aqueous Solutions by Radioisotopic Excited Fluorescent Spectrometer and by Conventional X-Ray Spectrometer
Authors: Chan Frank L. , Jones W. Barclay
Published: March 2019

An x-ray spectrometer with experimental results is herewith described using a radiosotope source Fe55 having a halflife of 2.6 years. As a result of the disintegration, the managanese x-rays are capable of exciting fluorescent x-rays of such elements as sulfur, chlorine, potassium, calcium, scandium and titanium in aqueous solutions. These elements with the Ka wavelengths ranging from 5.3729 Å to 2.7496 Å may be designated as between the very soft x-rays on the one hand and the hard x-rays on the other. The x-ray spectrometer presently described has achieved a resolution of 136 ev, FWHM.

Simultaneously, these elements have also been quantitatively determined by conventional x-ray fluorescent spectrometers. Since one of the spectrometers is designed to operate in vacuum as well as in helium or air, determination of sulfur, potassium and calcium were carried out in vacuum. Determination of chlorine was carried out in a helium atmosphere, Calcium, scandium and titanium were determined in air with an air-path spectrometer.

In the present study aqueous solutions containing these elements were used. The use of aqueous solutions has the inherent advantages of being homogeneous and free from effect of particle size.
Application of a Computer-Coupled Radioisotope X-Ray Spectrometer to Analysis of Steels
Authors: Rhodes J. R. , Hunter C. B. , Kellogg D. L. , Sieberg R. D. , Furuta T.
Published: March 2019

A compact X-ray energy spectrometer has been developed consisting essentially of a radioisotope X-ray source, a lithium-drifted silicon (or germanium) detector and a small computer. Interchangeable sources enable efficient excitation of K X-rays from Na to U and L X-rays from about Ag to U. Energy resolution of K X-rays from adjacent elements down to Na is possible. Depending on the source and the part of the spectrum examined, the characteristic X-rays from up to about 15 elements can be simultaneously excited and measured, for either qualitative or quantitative multi-element analysis. The computer stores detected spectra and performs simple data processing such as peak recognition, background subtraction, peak integration, ratioing and solution of linear equations.

The analysis reported in this paper is the determination of V, Cr, Fe, Co, W and Mo in tool steels and is intended to illustrate the capabilities of the radioisotope X-ray fluorescence analysis technique, and the instrument, for multi-element analysis of a system having fairly complex interelement effects.

A 100 mCi Pu-238 source was used to excite the K X-rays of V, Cr, Fe, Co and Mb and the L X-rays of W. The count time used was five minutes per sample. Data reduction consisted essentially of peak integration, background subtraction and solution of sixth order linear matrices of a modified Criss-Birks type. The 36 matrix coefficients were determined using six standards, and were then used to analyze seven other analyzed specimens which were treated as unknowns. The measured values of concentration were in very good agreement with the quoted values. An iteration technique was employed to reduce errors in the matrix inversioiis.