bluuebunny/crossref_metadata_2025 huggingface dataset:
Instantaneous Display of X-Ray Diffraction using a Diode Array Camera Tube
Authors: Chester Arthur N. , Koch Fred B.
Published: March 2019

The silicon diode array camera tube, recently developed for PICTURFPHONE® service, was modified to permit X-ray imaging. High quantum efficiency is attained without the use of a phosphor screen, since each photon absorbed in the silicon target generates several hundred hole-electron pairs for each keV of its energy, most of which can he usefully collected. The sensitivity and resolution are adequate to allow a continuous television display of the diffracted intensity as a crystal is oriented. Particular advantages of this technique include; high resolution (< 25 μm); electronically variable magnification; direct oscilloscope measurement of X-ray spot Intensity profiles and relative spot intensities because signal current is directly proportional to photon flux; high sensitivity in the range of 0.6 to 5.0 Å, potentially limited only "by counting statistics; integration times variable from < 1/60 second to minutes; and expected low cost, since the camera tube has no complicated electron imaging, and is directly interchangeable Mith a standard television vidicon. Applications which are described include crystal orientation and X-ray topography.
An X-Ray Lime Shape Study of HP 9-4-45 Bainites and Martensites
Authors: Klems George J. , Pascover J. Stephen
Published: March 2019

The broadening of the (110)α and (220)α powder pattern peaks of bulk samples from the product of two commercial 70 ton heats of a 9Ni-4Co-0.45C alloy (HP 9-4-45) was studied by Fourier analysis. Both heats were heat treated to a variety of bainitic and tempered martensitic structures and the effective particle size and r.m.s. strain in the <110> direction were measured. Comparison of the mechanical properties with the parameters derived from the Fourier analysis suggests that neither the strain nor the particle size are controlling the strength or toughness. Strength increases with Strain while toughness decreases - both as expected. On the other hand, large particle size seems to favor greater toughness in contrast to the known effect of macroscopic (high angle boundary) grain size.

It is concluded that line shape analysis is a convenient method of investigation giving repeatable parameters which represent the transformation strains. The extension of this technique to these highly strained, metallurgically complex structures appears justified.
Homogeneity Characterization of NBS Spectrometric Standards IV: Preparation and Microprobe Characterization of W-20% Mo Alloy Fabricated by Powder Metallurgical Methods
Authors: Yakowitz H. , Michaelis R. E. , Vieth D. L.
Published: March 2019

A significant problem of the National Bureau of Standards Standard Reference Materials program is the provision of standards suitable in homogeneity for use with microanalytical techniques such as the spark source mass spectrograph and the electron probe microanalyser. An interim approach to the problem has been the extended homogeneity characterization of selected existing standards. This paper describes the preparation and evaluation of the first NBS standard tested specifically from the beginning for application to electron probe microanalysers. The standard designated SRM 480 is a tungsten-20 weight percent molybdenum alloy prepared by a powder metallurgy process. Based on the results of about 1500 determinations for both tungsten and molybdenum by electron probe microanalysis, the material was found to be of high homogeneity at about the micrometer leve 1 of spatial re so lution. The coefficient of variation for molybdenum was 2.5% and that for tungsten 1.5%. Correction of relative intensity ratios to obtain concentrations is discussed in terms of input parameter uncertainties such as mass absorption coefficients, and electron backscatter factors. The result of studies for atomic number correction and effects on operating voltage on the microprobe absorption correction, will be given. It is concluded that SRM 480 should be a valuable addition to any microprobe laboratory doing quantitative analyses.
A Rapid and Accurate X-Ray Determination of the Rare Earths Elements in Solid or Liquid Materials using the Double Dilution Method
Authors: Tertian R.
Published: March 2019

The double dilution method has many important advantages. For any element to be determined, let us say A, It enables us to control or calculate the matrix factor (sum of the absorption end enhancement effects) for the sample being Investigated towards A radiation, and it furnishes corrected Intensities which are strictly proportional to A concentration. Thus the results are exact, whatever the general composition of the sample, their accuracy depending only on the quality of measurement and preparation. Another major practical advantage is that the method does not require systematic calibration but only a few permanent standards consisting of a pure compound or of an accurately known sample.

The procedure has been tested successfully for accurate determination of rare earth elements using, for solid materials such as ores and oxide mixtures, the borax fusion technique. It also can be readily applied to liquids. All the rare earth elements can be titrated by that method, as well as yttrium, thorium and, if necessary, all the elements relevant to X-ray fluorescence analysis. The concentration range considered for solids is of one comprised between 0.5 and 100 % and, with a lesser accuracy, between 0.1 and 0-5 % Examples are given relative to the analysis of various ores. Finally it rcust be pointed out that the method is universal and applies to the analysis of every solid, especially ores, provided that they can be converted to solid or liquid solutions. It appears that most industrial analyses can be worked on In this way.
Mass Absorption Coefficients and Quantitative Microanalysis of Refractory Metal Carbides
Authors: Gray Lawrence J. , Wert C. A.
Published: March 2019

Consideration of variations in atomic potentials permits an estimation of the mass absorption coefficients of many elements for the characteristic emission lines of carbon, nitrogen and oxygen. The accuracy of (μ/p) values presented is better than 5% in most cases. These values are tested in the microanalysis of defect titanium carbides. Limitations of the theoretical correction procedures lead to the definition, of a set of analysis conditions which permit carbon analysis to within 1.0% absolute.
Determination of Argon in RF Sputtered SiO2 by X-Ray Emission
Authors: Lloyd J. Charles
Published: March 2019

Argon is commonly used as the sputtering medium for RF sputtering of insulators and is entrapped in the deposits. X-ray emission determination of argon in RF sputtered SiO2 was required as part of a study of the relationships between argon concentration in the deposits and their electrical and physical properties.

Concentrations ranging from 0.05 to 7.4 weight % argon were measured in deposits 0.5 to 5μ thick. Two techniques were used for standardization: (1) weight loss of deposits heated for several hours in a helium atmosphere at 600°C; (2) potassium Kα and chlorine Kα measurements on a KCl film of known thickness to infer argon mass/argon Kα net counts. Calibrations made using these procedures agreed to within 10% and are reliable to about ±25% on an absolute basis. Absorption of radiation by the deposits was taken into account and used to correct measured argon intensities for absorption.

Sputtering parameters which had major effects on argon concentration were the substrate temperature and the magnetic field applied during sputtering. Argon pressure and RF power were found to have lesser effects.
Rapid Determination of Ash in Coal by Compton Scattering, Ca, and Fe X-Ray Fluorescence
Authors: Renault Jacques
Published: March 2019

The intensity of Compton scattering, Fe, and Ca chatacteristic radiation can be used to estimate the amount of ash in coal by Xray fluorescence spectroscopy. Mo, W, and Cr radiation were used to study a suite of New Mexico coals, and the best results were obtained with Mo and W X-ray tubes. If the actual concentrations of Fe2O3 and CaO and the mass absorption coefficient, μ*, at the Compton wavelength of scattered Mo K radiation can be determined, the regression equation:

%Ash - 24.2μ* - 6.28(%Fe2O3) - 1.96(%CaO) - 3.4

estimates the ash content with an average error of 0.5% ash at 0.71Å.
Elemental Analysis of Uraniferous Rocks and Ores by X-Ray Spectrometry
Authors: James Gerard W.
Published: March 2019

Large-scale uranium exploration programs and industrial mine development require rapid and accurate analytical determinations of uranium and associated elements, at concentration levels ranging from a few parts-per-million to the per-cent range. The analytical requirements for associated suites of elements vary with application, but quality control and production practices in U.S. uranium mines and mills commonly require determinations of calcium, iron, copper, molybdenum, and vanadium, in addition to uranium. Previous work has demonstrated the capabilities of wavelength-dispersive x-ray spectrometric methods for many exploration applications. The purpose of this investigation is to assess the accuracy of x-ray determinations of uranium at ore-grade levels, utilizing both wavelength-dispersive and energy-dispersive spectrometers, and to discuss the acquistion of multi-element data.
X-Ray Spectrometric Determination of Sulfate in Natural Waters
Authors: Seils C. A. , Tisue G. T.
Published: March 2019

A recent surge of interest in sulfur in the environment has revealed the need for improved methods of analysis for sulfate, SO4=, in rain, freshwater and sediment interstitial fluids. Ion chromatography permits the rapid determination of SO4= in the ppm range (1 ppm = 1 mgL'1 = 10 μmol L-1 sulfate) on relatively small samples with good specificity. If a suitable instrument is available, this technique is a good choice for many environmental analyses. Other approaches to sulfate analysis are based on its precipitation with organic or heavy metal cations, usually barium or lead. The amount of precipitate formed may be determined by inter alia gravimetry, turbidimetry, radiometry (using 133-Ba), atomic absorption spectrophotometry (Ba or Pb detection), potentiometry (using a Pb++ ion selective electrode) , colorimetry, or by x-ray fluorescence spectrometry (Ba, Pb or S detection)(1). Because of our experience with x-ray fluorescence analyses, we chose to develop and test a procedure using that technique.
Nondestructive, Energy-Dispersive, X-Ray Fluorescence an Analysis of Actinide Stream Concentrations from Reprocessed Nuclear Fuel
Authors: Camp D. C. , Ruhter W. D.
Published: March 2019

In the event that nuclear fuel from light water reactors (LWR) is reprocessed to reclaim the uranium or plutonium, several analytical techniques will be used for product accountability. Generally, the isotopic content of both the plutonium and uranium in the reprocessed product will have to be accurately determined. One plan for the reprocessing of LWR spent fuel incorporates the following scheme. After separation from both the fission products and transplutonium actinides (including neptunium and americium), part of the uranium and all of the plutonium in a nitrate solution will merge together to form a coprocessed stream. This solution will be concentrated by evaporation and sent to a hold tank for accountability. Input concentrations into the hold tank could be up to 350 g U/ℓ and nearly 50 g Pu/ℓ. The variation to be expected in these concentrations is not known. The remaining uranium fraction will be further purified and sent to a separate storage tank. Its expected stream concentration will be about 60 g U/ℓ. These two relatively high actinide stream concentrations can be monitored rapidly, quantitatively, and nondestructively using the technique of energy-dispersive x-ray fluorescence analysis(XRFA).
Energy Dispersive XRF Composition Profiling Using Crystal Collimated Incident Radiation
Authors: Boettinger W. J. , Burdette H. E. , Kuriyama M.
Published: March 2019

In order to measure changes in composition as a function of distance (macrosegregation) in directionally solidified two phase samples, a well collimated incident x-ray beam is required for XRF analysis. This is accomplished using Bragg diffraction of AgKα radiation from a highly perfect Si crystal. Because the incident beam is also monochromatic, additional advantages are realized: a) the backgrounds caused by Compton and thermal diffuse scattering (TDS) of the incident beam are well localized in the energy spectrum and do not interfere with the fluorescent peaks, b) the TDS can be used as a monitor of the incident photon flux and hence eliminates often substantial errors caused by incident beam intensity fluctuations.

Using several prepared standards, the ratio of PbL counts to TDS counts was found to be a function of the total Pb content of the two phase microstructure, with a reproducibility determined only by counting statistics. Furthermore, the function was found to be nearly linear over a wide range of compositions. Standard methods of absorption or enhancement correction can be employed using this ratio. The spatial resolution, determined by profiling a sharp discontinuity between two metals, was 0.5 mm.

Macrosegregation data is presented for Pb-Sn two phase alloys whose compositions range from 35 wt % Pb to 70wt % Pb. Comparison of compositions with those determined by a titration method agrees to within 2 wt % for most of the metallurgical structures present in the work. Somewhat larger deviations were found for samples with high Pb contents with extremely coarse two phase microstructures.
Energy Dispersive X-Ray Fluorescence Analysis of Inks on Paper
Authors: Russ J.C.
Published: March 2019

Interest in the analysis of inks on paper has come primarily, although not exclusively, from forensic scientists. Two classes of problems are encountered: comparison of inks in different regions of a single document, to detect additions (such as adding a “ty” to your handwritten check for “nine” dollars) made with a visually similar but hopefully compositionally distinct ink; and verification of authenticity in documents (including stamps, stock certificates, currency, etc.) by the presence of specific tag elements in certain of the inks present.
A Plasma Controlled X-Ray Tube
Authors: McGee James F. , Saha Timo
Published: March 2019

Many x-ray tubes, used by crystallographers and others, operate with the aid of a tungsten filament in the region of 2500°K, The high operating temperature results in evaporation of the filament material with two serious consequences. The first is a finite but relatively short lifetime. The second is contamination of the target and windows with tungsten. In addition, if the tube is of the demountable type, connected to an oil-diffusion pump and a mechanical fore-pump, carbonaceous deposits can be a problem. In a typical tube, the filament is mounted within a centimeter or two of the target. The resulting radiant heating of the target presents additional cooling problems especially with low melting-point targets. Many if not all of the above objectional features are circumvented by a plasma controlled x-ray tube using a low pressure atmosphere of helium and a cage-like cathode fabricated from nickel wire-mesh. An experimental model has been operated for several hours at 15 kv and 10 ma on an aluminum target. Scaling up of the apparatus will permit power dissipations in the kilowatt range limited mainly by the available power source or vaporization of the target material.
New Mold Design for Casting Fused Samples
Authors: Taggart Joseph E. , Wahlherg James S.
Published: March 2019

Geological samples prepared for analysis by X-ray fluorescence (XRF) are particularly prone to intrasample and intersample phase variations creating significant inhomogeneity and variations in matrix effects. These features may “best be eliminated or diminished by fusion of the sample with, a suitable flux (1,2). Presentation to the X-ray spectrometer may be as a briquet of the comminuted fusion head (1,3,4,5) or as a molded glass disc or wafer (l,2,5,6). Because of the stability of glass discs and the necessity to eliminate possible contamination during grinding and making briquets, molded glass discs appear to be the best and easiest means of presentation.
Specplot - An Interactive Data Reduction and Display Program for Spectral Data
Authors: Goehner Raymond P.
Published: March 2019

The automation of analytical equipment is proceeding at a rapid pace, particularly since the introduction of inexpensive microcomputer systems. Most of this equipment has one characteristic in common, that is, they produce digital spectral data. The usual method of recording spectral data has been the strip chart recorder. Strip charts require the hand encoding of position and intensities of the spectral lines. This requires that all of the lines be on scale or that the sample be run several times in order to amplify weaker lines. This problem is eliminated by recording the data digitally. Digital data can then be rapidly plotted on a cathode ray terminal to any desired scale. The user of digital data has access to a great variety of automatic data reduction programs.
X-Ray Emission from High-Temperature Laboratory, Plasmas
Authors: Nagel D. J.
Published: March 2019

The radiation from plasmas hotter than 106K falls in the x-ray region. Such plasmas are required for fusion power generation. They can also be used as x-ray sources. Measurements of x-ray emission from high temperature plasma yields (a) diagnostic information on the plasma conditions and (b) the characteristics of plasma x-ray sources which determine their applications. Hence, measurements of x-rays from plasmas are finding widespread use.
Determination of Actinide Elements in Nuclear Fuels by X-Ray Analysis
Authors: von Baeckmann A.H.E. , Ertel D. , Neuber J.
Published: March 2019

X-ray fluorescence analysis has been used for some years at two Institutes of the Karlsruhe Nuclear Research Center to determine routinely thorium, uranium, and plutonium in unirradiated and irradiated nuclear fuels. It has "been used in addition to assay neptunium, americium and curium contained in irradiated samples. The method excels because it is versatile, rapid, tamperproof, and efficient. As a rule, fission products, pollutions, and foreign activities do not interfere with the determination which can be made in a direct way without chemical separation. In practice, the nuclear fuels are dissolved prior to the analysis and a given amount of an appropriate element as an “internal standard” is added. The accuracies attainable (1 σ RSD better than 1 %) are comparable with the mass spectrometric isotope dilution analysis so that in the input analysis of reprocessing plants X-ray fluorescence analysis constitutes a true alternative to the mass spectrometric isotope dilution analysis.

Within the efforts to automate the method the prototype of the fully automated system is presently tested with non-active material. A first, not yet fully automated, development stage is being installed in the Karlsruhe Reprocessing Plant. It is anticipated that it will be tested soon under operating conditions. Complete automation of the system is scheduled to be completed at a later date.
Polarized Radiation for X-Ray Fluorescence Analysis†
Authors: Kaufman Leon , Camp David C.
Published: March 2019

The use of non-radioactive tracers for measuring certain clinically significant parameters by x-ray fluorescence analysis (XRFA) is well established at our institution (1,2). Among the technique's advantages are high accuracy, simplicity, cost effectiveness and reduced or eliminated radiation exposure to patients. One of the more versatile tracers is iodine, which has a low body toxicity and desirable chemical properties, e.g. it is easily bound to organic molecules. Other elements of interest are cesium (3), a potassium analogue of low toxicity; and xenon, the highest atomic number, stable, noble gas.
X-Ray Fluorescence Experiments with Polarized X-Rays*
Authors: Howell R. H. , Pickles W. L. , Cate J. L.
Published: March 2019

Two methods of obtaining polarized x-rays for fluorescence experiments are discussed. Compton scattering from a low-Z scatterer is the usual method used in such experiments. The polarization of x-rays undergoing anomalous Borrmann transmission in a dislocation-free crystal is also described and preliminary results are presented. Approximate expressions, useful for comparing scatter-polarizing systems, are derived for the dependence of scatter rejection and fluorescent efficiency on two scattering-system parameters: the thickness of the scattering polarizer and the geometric limit to solid angles and angular divergences in the system.
Proton Induced X-Ray Fluorescence Analysis Using a Cockcroft-Walton Accelerator
Authors: Bales D. I. , Landolt R. R. , Toll W. E.
Published: March 2019

The production of characteristic x rays by 100-keV protons has been studied to determine the feasibility of using a Cockcroft- Walton accelerator as an excitation source for x ray fluorescence analysis. Because of the low cross sections at this proton energy, it was necessary to concentrate on characteristic x rays below 6 keV and to use beam currents of 10 to 100 μA. The x rays were measured by a high resolution Si(Li) detector.

The preparation of various types of samples and the problems that arise when working at low proton energies and high beam currents are discussed.

It was found that the technique is useful for low atomic number elements down to less than 1 ppm in a water sample when there are no other significant impurities. When other elements are present, however, proton absorption becomes an important factor and quantitative determinations become very difficult. Proton absorption and its effect upon the usefulness of the technique are discussed.

The precision for the technique was determined and found to be better than 20% for most measurements. This includes errors in sample preparation which was considered to be a significant portion of the uncertainty.
Quality Control Through Determination of Interelement Effects in Iron-Gadolinium-Yttrium Solutions Using X-Ray Secondary Emission
Authors: Magathan E. M. , Short D. W. , Yocom R. L.
Published: March 2019

An analytical quality control procedure using x-ray Secondary Emission Spectrometry has been developed to monitor iron, yttrium, and gadolinium metal ion ratios in feed stock solutions. Binary and ternary laboratory standard solutions were analyzed to determine absorption and enhancement effects using approaches suggested by Rasberry-Heinrich, Beattie-Brissey, and Claisse-Quintin. A computation scheme combining these methods is presented which enables the user to improve his ability to predict composition. This approach has yielded relative errors of less than 1.0% for each of the three metals studied.
Charged Particle Induced X-Ray Analysis of Malaria Infected Blood
Authors: Barnes B. K. , Coleman R. M. , Kegel G. H. R. , Quinn P. W. , Rencricca N. J.
Published: March 2019

Blood samples from normal and Plasmodium berghei infected mice are being analyzed for trace elements by charged particle induced x-rays. Approximately 0.25 ml of the sample (whole blood, washed red cells, or plasma) is dry ashed. The ashes are mounted on a 0.003 inch Kapton foil. The analysis is performed by bombardment of the samples by a beam of 2.0 MeV protons and detection of the characteristic x-rays by a 175-eV-resolution lithium-drifted silicon detector. The data are analyzed by an on-line PDP-9 computer-based data acquisition system. Results indicate an increase in the K, Ca, Cu, and Zn per unit volume of the red cells of the malaria infected mice relative to the amounts measured for uninfected blood, and a decrease in the K, Ca, and Fe and an increase in the Cu per unit volume in the plasma of the infected mice.
Use of Calculated Alpha-Coefficients in Quantitative X-Ray Spectrometry
Authors: Jenkins R. , Croke J.F. , Niemann R.L. , Westberg R. G.
Published: March 2019

At the present stage of development of mathematical correction procedures, the so-called empirical methods are well established and reasonably reliable, require relatively small computers for their application, but require large numbers of calibration standards for the determination of the (alpha) correction constants. On the other hand, the so-called fundamental methods are less well proven and require more sophisticated computing facilities. One possible means of achieving the advantages of both techniques is to use a large computer to calculate the alpha coefficients from fundamental constants, then to use a small online computer for their application in an "empirical type" algorithm. de Jongh has proposed such a program called "ALPHAS" for the calculation of interelement correction constants and the present paper elaborates on this approach using as examples data collected in our own laboratory during the past year or so.
A Multiple Regression Procedure for Elemental Analysis at Low Concentrations
Authors: Mencik Z. , Berneburg P. L. , Short M. A.
Published: March 2019

Using a multiple regression procedure, X-ray fluorescence analysis has been applied to a 15-element system associated with ceramic supported automobile emissions catalysts. An equation taking inter-element effects into account was used to relate the concentrations and X-ray intensities of the active elements and contaminants deposited on the ceramic substrate. The major elements present in the substrate were intentionally excluded from the regression. The regression coefficients were determined from a set of 240 calibration standards using a multiple linear least-square regression. Elemental concentrations in the standards ranged from 0.05 to ten weight percent. The ceramic matrix was the same in both the standards and the unknowns to be analyzed and constituted at least 85 percent of the total weight of each sample. The regression coefficients were then used to solve for the contents of the elements in unknown samples. Limits of accuracy were determined by using the set of available standards. The performance of the regression was improved in certain cases by imposing constraints on the regression.
A High Intensity, Monochromatic, Spatially Coherent X-Ray Source
Authors: Burns S. J.
Published: March 2019

An x-ray source is described that can have high brilliance, monochromaticity and spatial coherence. This source filters, by successive diffraction, spontaneous x-ray radiation produced by electron impact in a Bonse-Hart monolithic crystal monochromater. A germanium single crystal was grooved to form a monolithic monochromater and subsequently was fitted with a filament. Field emitted electrons from the filament impact on the crystal side walls. Thus, the passive Bonse-Hart monochromater is converted into an active x-ray source. The detailed diffraction geometry within the cavity, in the limit of kinematic diffraction theory, is described and compared to the experimentally observed radiation pattern. Since this radiation source achieves its monochromaticity and spatial coherence by filtering it is highly inefficient. However, the diffraction process is highly efficient when the radiation is in the proper geometric direction to satisfy Bragg's law. Thus, the stationary radiation source can have a high brilliance although the input of electrical energy could be well in excess of a rotating anode x-ray tube.
Crystallite Orientation Analysis from Incomplete Pole Figures
Authors: Morris Peter R.
Published: March 2019

The use of incomplete pole figures results in the loss of orthogonality relations among the associated Legendre functions, and necessitates explicitly evaluating integrals of products of these functions. The required indefinite integrals of associated Legendre functions and their products have been evaluated for cubic crystallographic symmetry and orthotropic physical symmetry through sixteenth order.

The solution has been particularized for {200}, {222}, and {110} back-reflection pole figures, where data are confined to the region not exceeding 60 degrees from the sheet normal direction.

Data obtained from a sample of low—manganese steel sheet are used to illustrate the method, and results are compared to those obtained using complete pole figures obtained with a composite sample of the same material.

The method described makes it possible to study crystallite orientation distribution as a function of distance from the sheet surface, by a series of pole figure measurements on the surface after successive material removals by polishing and etching.
Bone Mineral (Apatite) Assay by Photon Scattering - A Survey of Sources and Experimental Evaluation
Authors: Preuss Luther E. , Piper Dennis G. , Bugenis Claudius
Published: March 2019

Current methods of measuring bone mineral content In vitro are either inaccurate or measure density in non-intuitive units. A recently developed system overcomes these difficulties by utilizing the Compton scattering of photons from bone. Two sources of monoenergetic photons with related properties are required. The range includes energetic x-rays and low energy gamma rays. This study analyzes a number of the possible nuclide source combinations, and reports experimental results accomplished with a 153Gd-170-Tm combination. In vitro measurement of the density of ox bones by this method agreed with Archimedean measurements within three percent.
Microprobe Analysis of Soil Erosion Aerosols
Authors: Gitlin Sonia N.
Published: March 2019

Pure standards of molybdenum disulfide, silver, and calcium silicide particles 0.5 μm in diameter and larger, were used to obtain calibration curves for size effect on x-ray intensities. The decrease in intensity with size follows a straight line down to about 3 μm. For the smaller sizes the intensities decrease exponentially. Good agreement has been found between curves calculated using simplified models of diffusion volumes intercepted by the particles and curves of measured x-ray intensities.

The intensity versus size was plotted as a percentage of the intensity of a flat, infinite standard. Therefore, the number of counts measured for a sample of known size can be converted to the intensity it would have if it were an infinite surface. These values can then be plugged into existing computer programs for quantitative analysis. Samples of atmospheric aerosols were analyzed by using these calibration curves.
Crystallinity, Crystallite Size and Lattice Perfection in Fibrous Polymers
Authors: Johnson D. J.
Published: March 2019

The X-ray diffraction patterns from fibrous polymers are generally characterized by a small number of relatively broad overlapping peaks often overlaid with a diffuse halo. Single fibres give the same pattern as a parallel bundle of fibres, so that the pattern is equivalent to the rotation pattern of a single crystal. Despite the inherent difficulty of insufficient well-defined reflections, all commercially useful fibres have been indexed, starting with cellulose, through nylon 66 and polyester, to the more recent fibres, such as Nomex and Kevlar. Only the structural complexities of the natural fibres of keratin (wool and hair) remain to be fully determined.

Many sophisticated computations have been carried out to refine unit-cell constants; unfortunately, much of this work is of doubtful value to those interested in fibre characterisation. Fibres are semicrystalline materials and their molecules are insufficiently well ordered for precision calculations of atomic positions. Indeed, there can be significant error involved in evaluating unit-cell constants from overlapping peaks, unless precise profile resolution is carried out.
Reproducibility and Precision of Measurements of Guinier Powder Patterns Using Powdered Silicon Calibrant
Authors: Brown A. , Edmonds J. W. , Foris C. M.
Published: March 2019

Calibrated powder patterns of a number of high symmetry crystalline materials were recorded in three different Guinier-type focusing cameras. The films were then measured by three different techniques, one visual and two instrumental. Cell parameters were calculated by three different data reduction procedures. The aim of the work was to establish the level of reproducibility for cell parameters obtained in routine work with these instruments.
Time-Resolved X-Ray Powder Diffractometry Using Lihear Position-Sensitive Proportional Counters
Authors: Göbel Herbert E.
Published: March 2019

Several examples of time-resolved X-ray powder diffraction studies with linear position-sensitive proportional counters (PSPC) are described. The changing patterns are recorded by spectrum multiplexing in a multichannel counter device. The time resolution for single processes is limited to seconds or tenths of seconds mainly because of the counting statistics of the observed peaks. Repetitive processes, however, where the interesting peaks can be accumulated over a large number of periods, permit much higher time resolution. It is finally determined by the timing of a detected X-ray quantum. Using a continuous beam source like a conventional X-ray tube the incidence of a photon into the PSPC can be timed with an accuracy of 20 ns (fwhm). A pulsed synchrotron radiation source, like a storage ring, will be able to define this resolution to its pulse duration, which is less than 200 ps.

Before approaching those limits this paper presents the high temperature phase transformations in iron for different steel specimens as an example of single processes. It also discusses domain-wall effects and electrostriction in ferroelectric perovskites as a function of polarization at frequencies of up to 10 Hz, and elastic lattice distortions of a steel sheet vibrating at about 200 Hz. The timing limit of 20 ns for the PSPC detection system was measured at the storage ring DORIS at DESY, Hamburg.
Technical Feasibility of a Borehole Probe for In-Situ X-Ray Diffraction Analysis
Authors: Borgonovi G. , Epperson D. , Houghton G. , Orphan V.
Published: March 2019

The mining industry uses coring as a standard method for the evaluation of ore deposits. Since coring is costly and time-consuming, increasing attention has been given to logging techniques capable of providing information about the orebody, thus allowing replacement of at least part of a coring program. An evaluation of the feasibility and potential for application of a variety of borehole logging techniques(l) concluded that X-ray diffraction (XRD) is one of the promising techniques for borehole assay, along with neutron activation analysis, X-ray fluorescence, photoluminescence, and infrared spectroscopy.
Internal Standards for Quantitative X-Ray Phase Analysis: Crystallinity and Solid Solution
Authors: McCarthy G.J. , Gehringer R.C. , Smith D.K. , Injaian V.M. , Pfoertsch D.E. , Kabel R.L.
Published: March 2019

Quantitative phase analysis by X-ray diffraction (QTXRD) has been an established tool of analytical chemistry for more than four decades. Despite its age, this tool remains ascendant as the only universally applicable method for determining the manner in which elements are combined into crystalline phases in multiphase solids. QTXRD is entering its second renaissance. The first came with the introduction of the counter diffractometer in the late 1940's. The specimen preparation and data collection processes were exacting and tedious, but reasonably accurate analyses could be obtained. The second came with the introduction of computer controlled diffractometers, whose software packages include QTXRD routines, in the late 1970's. With the tedium of data collection and analysis greatly reduced, we can expect even more widespread adoption of this tool in the general analytical laboratory.
The Application of an Automated Single Crystal Orienter for Large Specimens
Authors: Karg A. V. , Walsh J. M. , LaGrotta J. M.
Published: March 2019

A special purpose, automated, four circle goniometer arrangement has been developed for the rapid orientation of large specimens of single crystal turbine hardware. This system rapidly establishes the complete orientation of these large components and generates a fully documented stereographic projection. The system is also capable of generating detailed information on crystal quality including rocking curves in several dimensions. X, Y translational capability of the specimen makes it possible to characterize crystallographic defects such as sub-grain boundaries.
X-Ray Fluorescence Analysis of High Z Materials with Mercuric Iodide Room Temperature Detectors
Authors: Nissenbaum J. , Holzer A. , Roth M. , Schieber M.
Published: March 2019

Mercuric iodide HgI2 room temperature solid state radiation spectrometers having 4% energy resolution at 100 KeV detected the x-ray fluorescence (XRF) of the K shell of intermediate and high Z elements. The excitation of the K shells which emit XRF more energetic than 60 KeV was achieved with 7mCi collimated 57Co and for XRF less energetic than 60 KeV the excitation was done with a 10mCi 241Am source. The K shell XRF spectra of a 1:1 mixture of U and Th, and also of the single elements of Au, Tb, Ba, Ag, Mo, and Rb are shown. The results prove the feasibility of developing mercuric iodide portable XRF spectrometers which operate at room temperature and which have a wide range of geochemical and industrial applications.
Multiple Scattering and the Polarization of X-Rays
Authors: Zahrt John D. , Ryon Richard
Published: March 2019

In order to improve the overall performance of energy dispersive x-ray secondary emission spectrometry one can make use of polarized x-rays. We have used polarized x-rays produced by 90° scattering to reduce the background intensity due to the primary x-ray source.

An effort has been made to optimize the polarizing scatterer for the elements being analyzed. A discrepancy appears in the theory of such optimization between a simple one point formula and a more elaborate integral formula. Possible reasons for such disparities might lie in 1) collimator geometric effects, 2) multiple scattering and 3) actual primary intensity. The first problem has been dealt with in an unpublished manuscript. This report concerns itself with point 2, multiple scatter, and in particular with double scatter including polarization effects.
Advances in Low-Energy Electron-Induced X-Ray Spectroscopy (LEEIXS)
Authors: Bador René , Romand Maurice , Charbonnier Marlène , Roche Alain
Published: March 2019

Using low-energy electron induced X-ray spectroscopy (LEEIXS) with a cold cathode tube as excitation source and appropriate calibrations, quantitative surface composition informations are obtained. The results concern anodic film thicknesses and carbon impurities, In addition, qualitative informations on the chemical state of the film components are deduced from the fine structure of X-ray emission bands. The results concern oxygen K emission spectra from CuO and Cu2O, SnO, SnO2 and anodized Sn. It is also shown the capabilities of LEEIXS for gaining element-depth profiles, One example pertaining to phosphorus impurities in Al2O3 anodic films is given. Finally advantages and disadvantages of LEEIXS over ion-induced X-ray spectroscopy are discussed.
Leveling Device for Forming X-Ray Specimen
Authors: Won Vann Y.
Published: March 2019

A device was made for preparing accurate definition of surface, depth and volume of liquid x-ray fluorescence specimens.

The apparatus used in conjunction with a specimen holder and plastic film window material accurately and consistently forms a flat bobble-free analysis window on the open face of the specimen holder. The specimen holder in the form of a shallow cylinderical cup is slightly over filled and covered by the plastic film. Placement of the mating leveling apparatus over the film squeezes out trapped air bubbles, levels the exposed face of the specimen, draws the plastic film tightly over the exposed face of the specimen and allows easy installation of a film retaining O-ring to maintain the specimen material in a level state within the holder.
Monte Carlo Determinations of Optimal Photon Energies for XRF Analysis of Iodine In Vivo
Authors: Grönberg T. , Mattsson S.
Published: March 2019

After the pioneering work of HOFFER et al. on fluorescent scanning of natural iodine in the thyroid, several authors have suggested the use of X-ray fluorescence analysis to follow in vivo the distribution and elimination of stable tracers injected prior to the investigation. The normal method of performing such studies is to inject iodine containing contrast media and then follow the variation in iodine concentration by in vivo measurements over the organ or tissue of interest.

A theoretical treatment of the application of X-ray fluorescence in in vivo studies has been made by TINNEY by means of analytical calculations.
Analysis of Refractory Metals and WC-Based Hard Metals by Energy Dispersive X-Ray Fluorescence
Authors: Wegscheider Wolfhard , Müller Kurt , Ortner Hugo M.
Published: March 2019

The potential of energy-dispersive X-ray fluorescence spectrometry for analysis of refractory metals and WC-based hard metals is investigated. Both, photon excitation by filtered tube radiation and by the characteristic, lines of a secondary target are employed. Both excitation systems give good results. If the counting times are adjusted to account for the lower sensitivity of energy dispersive as opposed to wavelength dispersive X-ray spectrometry the detection limit and precision data are comparable. The multielement analyses of interest in these applications that comprise an energy range of 5 keV or more are better handled by direct excitation with filtered tube radiations than either by secondary target excitation or by wavelength dispersive X-ray spectrometry.
A Rapid and Precise Computer Method for Qualitative X-Ray Fluorescence Analysis
Authors: Huang T. C. , Parrish W. , Ayers G. L.
Published: March 2019

This paper describes a computer method for wavelength dispersive (WD) qualitative X-ray fluorescence (XRF) analysis. It determines the elements, spectral lines, wavelengths, reflection angles and peak intensities of the first and second order reflections in less than half a minute of time using an IBM Series/1 minicomputer. The resolution and precision are significantly better than the energy dispersive (ED) method and when combined with high speed computer recording the speed is comparable.
Monte Carlo Studies on the Design of Radioisotope Source Holders and Shields for EDXRF Analyzers
Authors: Doster J. M. , Gardner R. P.
Published: March 2019

Inherent in the use of radioisotope sources with secondary fluorescers is the background produced by scattering of the source photons from the exciter system. A Monte Carlo program has been developed that is capable of simulating the backscattered photon spectrum as a function of the system geometry, including shielding and collimation variations. This computer program generates the scattered photon spectrum incident on both the sample and detector. The program is applied to a commercially available exciter system to study the effect of specific geometric design changes on the scattered spectrum.
A Survey of Mathematical Correction Procedures in X-Ray Spectrometry
Authors: Jenkins Ronald
Published: March 2019

X-ray spectrometry is an old technique dating back some sixty-odd years and although most of the early interest revolved around the qualitative aspects of the method it wasn't long before attempts were made to obtain quantitative data. One of the first recorded attempts was that by Coster and von Hevesey who in 1923 accurately determined the amount of hafnium in zirconium using tantalum as an internal standard. Glocker and Schreiber were the first to attempt calculation of X-ray characteristic line intensity from first principles although no attempt was made at that time to correct for secondary fluorescence. In von Hevesey's book, “Chemical Analysis by X-Rays,” published in 1932 , a whole chapter is devoted to what is called “Disturbing effects and their avoidance.” Among the effects discussed were primary and secondary absorbtion and third element effects. Matrix correction equations were developed although most of the quantitative work at that time was done using internal standards.
Statistical Considerations in X-Ray Fluorescence Analysis
Authors: Short M. A.
Published: March 2019

The role of statistics in certain areas of X-ray fluorescence analysis is considered. The topics discussed include: calculating the standard deviation associated with the result of an analysis; optimizing experimental parameters for both wavelength and energy dispersive analyses; evaluating limits of detection, limits of decision, and limits of determination; and weighting in the least squares fitting of data in single element polynomial relationships and in multi-element multiple regression analysis.
An Accurate Coefficient Method for X-Ray Fluorescence Analysis
Authors: Tertian E.
Published: March 2019

Performing highly automated, computerized X-ray spectrometric analysis ‘without standards’ calls for accurate matrix correction programs which can be based, essentially, on either the ‘fundamental parameter’ method or improved influence coefficient procedures. The coefficient scheme discussed in this paper was devised to strictly comply with the theoretical relationships for X-ray fluorescence emission, thus connecting, in a way, both approaches. This result is achieved by accurately making allowance for the two complicating factors affecting fluorescent intensities i.e. : (1) the mobility of coefficients, and (2) the occurrence of fluorescence crossed effects. The corresponding algorithm, for practical use, writes

where the (aij + bij ci) terms account for the individual influence coefficients and their variation, and ϵi refers to the overall crossed effect. The essential problem of calibration is then considered, with special emphasis being laid on : (a) experimental coefficient determination, and (b) experimental crossed effect evaluation. Current coefficient methods are briefly surveyed in relation to the present theory.

Finally, the advantages of an experimental, accurate coefficient procedure over the fundamental parameter approach, from a practical standpoint, are emphasized.
Quantitative Microprose Analysis with Energy Dispersive Detectors - A Status Report
Authors: Lifshin E.
Published: March 2019

Methods for quantitative microprobe analysis of flat samples with energy dispersive spectrometers are reviewed for the case when the electron beam is well contained in the analyzed region. Particular attention is paid to models for background subtraction and peak overlap necessitated by limited energy resolution. Present indications are that careful data collection procedures can often lead to accuracy comparable to crystal diffraction spectrometers.