bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Epitaxial Films by X-Ray Diffraction
Authors: Segmüller Armin
Published: March 2019

In this paper, the application of recently developed x-ray diffraction techniques to the characterization of thin epitaxial films will be discussed. The double-crystal diffractometer, with high resolution in the non-dispersive arrangement, enables the materials scientist to study epitaxial systems having a very small mismatch with high precision. A key part of the characterization of an epitaxial film is the determination of the strain tensor by measuring lattice spacing! in various directions The determination of strain and composition profiles in ion-implanted films, epitaxial layers and superlattices by rocking-curve analysis will also be reviewed. Grazingincidence diffraction, an emerging new technique, can be used to obtain structural details parallel to the interface on films with thicknesses ranging down to a few atomic layers. The synchroton has now become increasingly available as a powerful source of x radiation which will facilitate the application of conventional and grazing-incidence diffraction to ultra-thin films.
EDXRF Analysis of Thin Films and Coatings Using a Hybrid Alphas Approach
Authors: Kalnicky Dennis J.
Published: March 2019

In the semiconductor and electronics industries the processes Involved in producing integrated circuit soften require thin films such as P205/SiO2, Si/Al, Ni/Cr, Fe/Ni, or others to be deposited on a substrate wafer. It is critical to the performance and life time of the device that the composition and thickness of these films be precisely controlled. The ability to quickly analyze wafers provides data which can be used to adjust fabrication parameters before large quantities of devices are lost.
Resolution of Overlapping X-Ray Fluorescence Peaks With the Pseudo-Voigt Function
Authors: Huang T. C. , Lim G.
Published: March 2019

A method for resolving overlapping X-ray fluorescence spectra by curve fitting is described. The profile shape of an experimental fluorescence line obtained by wavelength dispersive method is represented by a simple pseudo-Voigt function, i.e. a sum of an asymmetric Gaussian and Lorentzian, each of equal width. Results showed that the pseudo-Voigt function matched the experimental profiles with high reliability. The relative Gaussian and Lorentzian contents and the asymmetry of the profiles depended upon the analyzing crystal, coliimating system and the 2θ peak position. For fixed crystal and collimator the smaller the 2θ, the larger the Gaussian content and the lower the asymmetry. The original Gaussian and Loretzian components of the exact Voigt function calculated from the parameters of the fitted pseudo-Voigt function explain the broadening effects of the X-ray emission lines and the instrumental aberrations on observed spectra. Curve fitting method with the psuedo- Voigt function has been used successfully to analyze overlapping fluorescence spectra. Examples and applications include a thin film sample where the Kα and the Kβ lines of adjacent transition elements overlap, and a strontium zirconium oxide specimen where the Zr Kα and the Sr Kβ lines strongly interfere. Concentrations obtained from the resolved individual peak intensities of Zr and Sr Kα lines are within ±1% of the true values.
Determination of Nickel and Vanadium in Crude Oil Using Wavelength Dispersive X-Ray Fluorescence Spectrometry and a Tight Standardization Method*
Authors: Mansour S. , Abu-Dagga F. , Sabri R.
Published: March 2019

Metallic impurities present in crude oils lead to the rapid deactivation of catalysts used in refineries and a drop in the yield of oil products. The determination of these impurities is therefore of primary importance. The conventional and most widely used methods to determine trace metals in oils and petroleum products are chemical analysis methods such as atomic absorption spectrometry (AAS) and inductively coupled plasmaoptical emission spectrometry (ICP-OES). Sample preparation for these methods includes decomposition of the crude sample by dry ashing and combustion of the oil sample followed by chemical treatment of the dry ash residue (ASTM, 1983; Fassel et al., 1976). Major drawbacks of chemical analysis methods are the length of time required to prepare the sample and the possibility of losing trace metallorganic compounds in the form of volatile compounds.
X-Ray Diffraction Topography-Differential Omega Scanning Technique
Authors: Silver Ray L. , Turner Jack C.
Published: March 2019

The Differential Omega Scanning Technique (DOST) was developed to improve topographs obtained from silicon wafers which generally possess process induced flexure during the manufacture of semiconductors products. A commercially available Lang camera has been electronically instrumented to provide an automatic adjustment of omega motion of the specimen on the goniometer axis. The position of the specimen relative to the primary beam (theta) is continually altered by DOST to assure maximum, or near maximum, diffraction intensity with changes of flexure of the wafer as the specimen is scanned. The resulting topographs have near complete images and appear to have improved quality. Using techniques developed within the x -ray laboratory, routine acceptable topographs are obtained in only the time required to scan the diameter of the specimen one time.
A Modular Automatic X-Ray Ahalysis System
Authors: Slaughter M. , Carpenter Davis
Published: March 2019

A modular x-ray and electron beam system has been constructed to accomplish most standard types of x-ray analysis automatically. The system includes a vertical powder diffractometer, a vacuum spectrograph, a four-axis single-crystal diffractometer and an electron microprobe with four spectrometers. The system is controlled by a single computer with auxilliary drum storage. The powder diffractometer has automatic goniometer drive, automatic sample changing with computer cataloging of samples and automatic variable divergence slit. The x-ray spectrograph is a standard unit with added 100 KV capability, automated goniometer drive, eight or 32 position sample changer, six-analyzing-crystal changer, collimator changer, and detector changer. All functions including sample number cataloguing are computer controlled. The four-axis single crystal diffractometer has all functions computer controlled and includes peak search option. The electron microprobe/scanning electron microscope has all spectrometers, x, y, z stage motions and sample changer controlled by computer. X-Ray channels, beam current and sample current are automatically read-out. Control of probe functions and correction of mechanical errors in stage operation, are aided by a digital beam scanner with a light pen. Counting channels and computer interfacing are modular, and channel components are interchangable by the operator. Computer hardware may be expanded and the software is modular. Any combination of instruments up to eight may be operated.

The computer operates all instruments simultaneously in a time-sharing mode. Programs consist of operating system programs, individual instrument programs and data processing programs. The operating system drives all x-ray hardware, fetches programs and data from the drum, allocates data storage, queues final results for printing and performs other necessary executive functions. For qualitative analysis, spectra for each instrument are collected automatically in several modes and are stored on the drum. A variety of methods are used to remove background, strip unwanted peaks and find peak position and intensity. A.S.T.M. diffraction, spectrographic and special files are maintained on the drum. Quantitative analysis is executed automatically using a version of "MAGIC" on the electron microprobe and a multiple linear regression method for the spectrograph and diffractometer.
Energy Dispersive Analysis for Adjacent Elements Using Two Single Channel Analyzers
Authors: Chow Hubert K.
Published: March 2019

Energy dispersive x-ray analysis has become an extremely useful analytical tool. The technique provides for the direct observation of x-ray emission spectra, eliminating the need for a dispersive crystal. The purpose of this reported investigation was to study the use of the technique with a simple pulse height analyzing system and to develop a routine method for correcting Interferences due to adjacent element spectral overlap and matrix effects.

The analyzing system consists of a radioisotope source, a lithium drifted silicon detector, a preamplifier, an amplifier, two single channel analyzers and two digital ratemeters. In order to obtain results suitable for quantative measurement, a two-step empirical method was employed for the correction of peak overlapping and matrix effects. If two peaks in a spectrum overlap at their tails, one can set up a channel width of the analyzer to a region where there are no overlapping pulses. It is then possible to calibrate the ratio of the intensity obtained from this channel to that obtained from the whole peak in its pure state, i.e. without the appearance of a neighbor peak. The actual intensity of the peak in the overlapping spectrum is, therefore, the observed counts multiplied by the ratio. The next step is the correction of matrix effect by means of conventional empirical methods using standard samples. Two types of the samples, Zn-Cu powder mixtures and Ee-Cu in aqueous solutions, were studied to illustrate this method. The usefulness of applying the analyzing system and technique to industrial measurements, either on-line or batch, will also be discussed.
Rapid Recording of Powder Diffraction Patterns With Si(Li) X-Ray Energy Analysis System: W and Cu Targets and Error Analysis
Authors: Sparks Cullie J.
Published: March 2019

X-ray diffraction patterns using continuous radiation from copper and tungsten target x-ray tubes and detected with a Si(Li) energy analysis system are presented. Errors caused by a misaligned diffractometer and x-ray penetration into the sample are shown to be more difficult to correct and larger in magnitude than errors arising from energy calibration. All these errors can be minimized by mixing a standard with the unknown sample.

The energy resolution of the detector influences the breadth of the diffraction peaks more strongly than the standard slit systems available with commercial diffractometers. Thus, to reduce the recording time and maintain the same standard deviation for the data, one should increase the sizes of the front and receiving slits including the Soller slits. X-ray energy diffraction patterns can be recorded with standard deviations less than +0.001 Å in the d spacing with only 200 sec measurement time using the standard diffractometer slit system. Copper targets are probably as useful as tungsten even though the continuous intensity is about three times.less. Copper has fewer interfering characteristic lines, and its use permits convenient conversion to normal θ scanning diffractometer operation.
A Computerized Technique of Plotting a Complete Pole Figure by an X-Ray Reflection Method
Authors: Klappholz J. J. , Waxman S. , Feng C.
Published: March 2019

The technique of plotting a complete pole figure composed of data points in both longitude and latitude from 0 to 180 degrees by a computer program is described. X-ray data were obtained by a reflection method from a specimen cut into three sections mutually perpendicular to one another. The computer program calculates each position in the pole figure based on the time rate of change of the tilt angle ϕ and the spin angle α which are transformed into rectangular coordinates.

The advantage of the present technique is to minimize the x-ray intensity loss due to geometric defocusing, since each section of a given specimen is required to tilt not more than 55 degrees. Due to the fact that a complete pole figure is plotted, one is allowed to examine the symmetry or lack of symmetry in a given specimen with respect to a set of references axes.
X-Ray Double Crystal Diffractometer Investigations of Implanted Silicon: D+And N+
Authors: teKaat E. H. , Schwuttke G. H.
Published: March 2019

Double crystal diffractometer measurements on silicon bombarded to a fluence >1016ions/cm2with 1 MeV deuterium and 2 MeV nitrogen are reported. Such measurements provide insight into radiation damage in silicon through the observation of Bragg case pendelloesung fringes and double peak rocking curves. Bragg case pendelloesung fringes are used to determine nondestructively the projected range of ions in silicon. Double peak rocking curves are used to measure changes in lattice parameter with the ion dose. Finally, a model of radiation damage in silicon is presented.
Quantitative X-Ray Fluorescence Analysis With Variable Take-Off Angle
Authors: Ebel H.
Published: March 2019

A solution of the intensity equation of X-ray Fluorescence analysis is possible either by the assumption of an effective wave length or by a variation of the take-off angle. When the intensity of the fluorescence radiation is measured as a function of the take-off angle, the extrapolation of this curve against take-off parallel to the flat sample surface offers a simple evaluation of the intensity equation. Since the influence of the secondary excitation is also taken in to account the composition and the mass per unit area of samples can be investigated as well as mass absorption coefficients and mean wavelengths of the polychromatic primary radiation.
Interpretation of Valence Band X-Ray Spectra
Authors: Nagel David J.
Published: March 2019

X -ray spectra arising from the valence bands of solids are useful for basic studies of the electronic structure of most materials and for practical measurements of unknowns to obtain information on local atomic structure and material properties as well as chemical composition. Understanding the characteristics of valence band spectra is prerequisite to their fullest use. One-electron and many-body aspects of the x-ray emission process, and the effects of experimental conditions, must be understood and are reviewed. Interpretation of spectral features and determination of electronic structure are complementary parts of one procedure which is based on the use of bonding theory. The various band and bond theories which are finding use for spectral interpretation are briefly reviewed. Calculation of the electronic structure of aluminum metal and quartz, and interpretation of their x-ray spectra, are examples which illustrate basic work with valence band spectra.
Point Scattering Theory of X-Ray K-Absorbtion Fine Structure
Authors: Sayers D. E. , Lytle F. W. , Stern E. A.
Published: March 2019

We calculate the extended X-ray absorption fine structure by treating the ejected photoelectron as a spherical wave which expands in the lattice and is partially scattered by neighbors of the absorbing atom. The neighboring atoms are treated as point scattered and the total scattered wave is summed from the waves scattered by each atom. The fine structure is determined from the dipole transition matrix between the initial K-state and the final photoelectron state. Calculations compare favorably with experimental data.
X-Ray Astronomy
Authors: Friedman Herbert
Published: March 2019

Although searches so far have been restricted to a few small rockets and balloons, some 40 discrete x-ray sources have already been resolved against a diffuse, nearly isotropic background radiation. The strongest source is about 2000 times as bright as the weakest detectable with present rocket instruments. Nearly all of the discrete sources lie close to the galactic plane and most likely are members of the spiral arms of the Milky Way. One x-ray source at high galactic latitude is identifiable with a distant radio galaxy, Virgo A, and its x-ray luminosity is 70 times its radio power. The diffuse background radiation seems to be resolvable into at least two components: one may be associated with the interaction of cosmic rays and the microwave photons of the cosmological 3 K background; the other with bremsstrahlung from hot, intergalactic gas.
Development of a Slitless Spectrograph for X-Ray Astronomy
Authors: Zehnpfennig T.
Published: March 2019

The soft x - ray slitless spectrograph is described, and its usefulness in making rapid surveys of wide spectral regions is discussed Fabrication of the 1μ thick gold-shadowed transmission gratings used in the instrument is described. Spectra taken in the laboratory and during a solar sounding rocket flight are presented. Because a simple absorbing strip model is inadequate to explain the distribution of intensities among the spectral orders, a phase-grating model must be adopted.
Application of the X-Ray Two-Exposure Stress Measuring Technique to a Carburized Steel
Authors: MacDonald Bruce A.
Published: March 2019

X-ray stress factors for a carburized steel were determined experimentally as a function of tempering temperature from loaded cantilever specimens . The standard X-ray stress expressions were modified to account for both the applied calibrating stresses and the biaxial residual stresses present in the surface of these specimens. The resulting equations permitted calculation of the ﹛ 211 ﹜ stress - free interplanar spacing, elastic modulus and Poisson's ratio from the X-ray data.

Tempering to higher temperatures reduced significantly the surface residual compressive stresses and stress - free spacing. The change in spacing with tempering of these specimens must be considered when determining elastic stresses by the one-exposure X-ray technique. Tempering also produced a linear relationship between the tempered hardness and ﹛ 211 ﹜ interplanar spacing.
A Dual Detector Diffractometer for Measurement of Residual Stress
Authors: Mitchell C. M.
Published: March 2019

The diffractometer employs dual fixed detectors and a moving, vertically mounted X-ray tube. Lattice strain is measured in two specimen directions simultaneously. The drive has three concentric shafts; the outer driven by a cone drive worm and gear; a middle fixed shaft supporting the detectors and an inner shaft geared in a 1:2 ratio carrying the specimen mount. Scanning angles are measured to an accuracy of ±0.001°. A large range of specimen sizes can be accommodated.
Chemical Analysis of Nickel Oses by Energy Dispersive X-ray Fluorescence
Authors: Wheeler Bradner D. , Bartell Daniel M. , Cooper John A.
Published: March 2019

Chemical analysis of geological materials such as nickel ores has been accomplished by atomic absorption (1,3) x-ray fluorescence (11,14) and conventional wet methods (10). Procedures utilizing these techniques are capable of producing excellent results but are often difficult and time consuming.

Minerals often present serious problems in chemical analysis by wet methods. X-ray analysis can therefore offer the analyst considerable savings in time providing the obstacles which exist are understood and minimized or eliminated. The most serious problems to solve are absorption and enhancement effects, mineralogical differences among samples, sample preparation, and particle size effects which often influence the intensities of the analytical lines. In addition, the element of interest may be of low concentration in a variable and unknown matrix.
An Interactive Program for the X-ray Specrometer , for Data Collection and Data Manipulation - Use in Qualitative Analysis
Authors: Jenkins R. , Myers Q. , Paolini F. R.
Published: March 2019

Computer controlled X-ray spectrometers have been available since the mid 1950's and there are many hundreds of these systems in use today. The degree of sophistication of these machines has increased gradually over the past several years, but in all cases the flexibility of the analytical system is directly relatable to the available computer hardware. In the design of any computer controlled X-ray spectrometer, it is highly desirable to keep the cost of the computer, plus its associated interfaces and software, to within a reasonable fraction of the total cost of the whole system. A figure of perhaps 30% or so is a good figure to aim for in this context. A compromise must, therefore, always be sought between cost and computational power--which generally means flexibility.
Comparison of the Hanawalt and Johnson-VAND Computer Search/Match Strategies
Authors: Cherukuri Satyam C. , Snyder Robert L. , Beard Donald W.
Published: March 2019

Over the past fifteen years two basic computer search/match strategies have evolved. The exhaustive search approach of Johnson and Vand (1) uses a sequential file structure whereas Nichols (2) developed a strategy which uses an inverted file, examining only those patterns containing lines of interest. Frevel (3) was the first to attempt to relate the quality of the reference patterns to the search strategy using a very restricted data base. These “first generation” search/match algorithms were forced to use very wide d and I windows due to the poor quality of the unknown and reference patterns.

Snyder (4) wrote the first “second generation” search/match procedure which takes advantage of high quality of data in the JCPDS data base when it is present. Recently, a minicomputer optimized version of the Johnson-Vand strategy has been incorporated into this search system enabling a chance to compare these two strategies under similar conditions.
XRD Quantitative Phase Analysis Using the NBS*QYANT82 System
Authors: Hubbard Camden R. , Robbies Carl R. , Snyder Robert L.
Published: March 2019

X-ray powder diffraction (XRD) is widely used for qualitative analysis of the phases in multiphase mixtures. To extend the characterization to the level of quantitative analysis (QA) requires solution of many challenging problems such as elimination of preferred orientation (1,2,3); selection of an appropriate reference standard which closely matches the analyte phase in crystallite size, thermal history, stoichiometry etc. (4); effectively collecting the experimental intensities (5,6); and finally, performing the data reduction and analysis.

The desire to solve the last problem in a general way and to incorporate the “best” procedures developed in several laboratories into one package was one of the stimuli for developing the NBS*QUANT82 system of programs. This system is integrally coupled with the data collection system AUTO (6,7).
A Method for X-Ray Stress Analysis of Thermochemically Treated Materials
Authors: Prümmer Rolf A. , Pfeiffer-Vollmar H. W.
Published: March 2019

X-ray stress analysis is a nondestructive method enabling one to measure residual and loading stresses in polycrystalline materials. Known as a difficult method for several decades, the introduction of microprocessors allowed the automation of the measuring procedure and the subsequent storage and computation of diffraction data. Also the availability of position sensitive counters increased the efficiency of the method. Nowadays a residual stress or loading stress determination can be a problem of a few minutes if the time required for installation and alignment of the equipment is neglected. As the penetration of the X-ray beam into the investigated surface of polycrystalline materials is low and only a few micrometers the obtained information is that of a surface stress state. A further specialty of the method is the selective nature of X-ray stress analysis: lattice strains are measured in certain crystallographic directions. Therefore the elastic anisotropy of the single crystal has to be taken into account. If second phases are present in the investigated sample, also the effect of heterogeneity contributes to the stress analysis. Therefore, the “X-ray elastic constants” had to be introduced.
X-Ray Diffraction Observation of Fracture Surfaces of Ductile Cast Iron
Authors: Yajima Zenjiro , Hirose Yukio , Tanaka Keisuke
Published: March 2019

X-ray diffraction observation of metal fractures provides fracture analysists with useful information on the mechanisms and mechanical conditions of fracturing. This method is called “X-ray fractography” and has been developed especially in Japan as a new engineering tool for fracture analysis.

In the present paper, X-ray fractography is applied to fracture surfaces of ductile cast iron (JIS FCD 60) which are widely used as machine parts. The fracture toughness tests were conducted at ambient and low temperatures by using compact tension (CT) specimens with blunt notches and three-point bending (TPB) specimens with fatigue pre-cracks. The line broadening of X-ray diffraction profiles was measured on and beneath fracture surfaces of fracture toughness specimens.
X-Ray Fluorescence Analysis Using Synchrotron Radiation
Authors: Gilfrich J.V. , Skelton E.F. , Nagel D.J. , Webb A.W. , Qadri S.B. , Kirkland J.P.
Published: March 2019

Synchrotron radiation (SR) has several unique properties which cause it to be used for many purposes in science and technology. It is continuous spectrally, collimated spatially, short-pulsed yet continuously-operating temporally, as well as polarized( 1). Many applications of SR have already been demonstrated. These range from production of fine scale structures by lithography to numerous studies of materials. Determination of atomic structure by diffraction and other scattering experiments and by absorption spectroscopy (EXAFS), and emission spectroscopic studies of electronic structure have been given most attention(2). Only limited attention has been paid to determination of materials composition by x-ray fluorescence analysis (XRF) employing synchrotron radiation. Sparks et al.(3-5) have performed the most notable experiments, examining mica inclusions for the presence of primordial super heavy elements and irradiating two National Bureau of Standards Standard Reference Materials (SRM 1571, Orchard Leaves and SRM 1632, Coal) to measure the fluorescent x—ray intensity from the trace elements.
A New Technique for Radioisotope-Excited X-Ray Fluorescence
Authors: LaBrecque J.J. , Parker W.C.
Published: March 2019

In this work we plan to describe a new simple technique for exciting characteristic X-rays for X-ray fluorescence. This technique was originally designed for use with β-emitting radioisotopes (1) but now has been extended to other types of isotopes.The technique involves mixing directly with the sample (about 20mg) a small amount of a radionuclide (about 100 μCi). An equal atomic mixture of the following elements was prepared: Ti, Mn, Zn, BrfAg, Sn,and Ba. This mixture was investigated with the following isotopes: Ni-63, S-35, Pm-147, Na-22, Co-137, I-125, Co57, Cd-109, Zn-65, Fe-55 and Am-241. A composite table of the corrected integrated Kα—lines of the elements in the mixture and Graphs showing the ratio of the Ka line intensity of the element of interest divided by the Kα line intensity of Ti will also be presented.
Elemental Analysis of Geological Samples Using a Multichannel, Simultaneous X-Ray Spectrometer
Authors: Cross J. B. , Wilson L. V.
Published: March 2019

X-ray spectrometry has been used successfully for major and trace element analysis of geological samples (e.g. reference 1). Its advantage is providing accurate and precise results in a rapid manner: a key factor in selecting analytical methods for mineralogical studies involving large numbers of samples. All elements with atomic numbers greater than 9 (fluorine), except noble gases, can be determined with sensitivities ranging down to ppm levels.

The analytical method described in this report is for the determination of the major elements (i.e. Na, Mg, Al, Si, P, K, Ca, Ti, Mn and Fe) in geological samples. Commercially available automated fusion devices are used for sample preparation.
Chemical Analysis of Coal by Energy Dispersive X-Ray Fluorescence Utilizing Artificial Standards
Authors: Wheeler Bradner D.
Published: March 2019

Accurate determinations of the elemental composition of coal by classical methods can be quite difficult and are normally very time consuming. X-ray fluorescence utilizing the powder method, however, has the ability of providing accurate and rapid analyses. Unfortunately, well characterized standards, although available, are not plentiful. In addition, the durability or stability of ground and pelletized coal samples is poor resulting in deterioration with time. As a result, artificial coal standards were prepared from certified geological materials by fusing in lithium-tetra-borate in percentages approximating expected ash contents and compositions in coal. Since the lithium-tetra-borate comprises about the same percentage of the standard as does the carbon, hydrogen, and oxygen in coal, the ground and pelletized coal sample can be assayed against the fused calibration curves by compensating for the differences in the mass absorption coefficients of the two matrices.
New Developments in FP-Based Software for Both Bulk and Thin-Film XRF Analysis
Authors: Feng Liangyuan , Cross Brian J. , Wong Richard
Published: March 2019

In the last decade, the Fundamental Parameter (FT) method has been increasingly used in quantitative XRF analysis as an effective means for interelement effect corrections. Many authors have contributed to its continuous development both in theory and practice [1 - 26]. Among various implementations, the FP-alpha method has been used widely in bulk-sample analysis because of its unique advantage of speed [1 - 6]. In recent years, however, with the advent of faster computers, a rigorous full FP approach has become feasible and practical. This is especially true in the field of multilayer thin-film, analysis, where the FP-alpha approach has not yet been applied.
Determination of Heavy Metals in Environmental Water by Total Reflection X-Ray Fluorescence Method using Optimized Roentgen Optics Cut-Off Filter
Authors: Egorov A. I. , Kablna L. P. , Kondurov I. A. , Korotkikh E. M. , Martynov V. V. , Shchebetov A. F. , Sushkov P. A.
Published: March 2019

The total reflection x-ray fluorescence (TXRF) method of analyzing elemental contents Is based on the small angle irradiation of thin samples placed on a total reflecting backing with a narrow photon beam. Two instrumental problems are to be solved here. The first is to form the narrow beam with a small angular deviation. The usual way to solve this problem is to use collimators with small solid angles. These angles must be less than the critical angle for x-ray total reflection, which, in the energy range 10 - 20 keV has an order of magnitude around 10−3 rad.
Variability of Crystal Performance in X-Ray Fluorescence Spectrometers
Authors: Dubrawski Jules V. , Turner Ken E.
Published: March 2019

The intensity performance of various common XRF crystals (LiF200, Ge, PET and LSM) has been investigated under fixed experimental conditions. Measured were the raw intensities of elements particularly suitable to a given crystal, and peak-to-background ratios at different elemental concentrations. Peak profiles for each crystal type were also recorded and analysed in terms of apparent crystallite size and mosaic spread. In general the LiF crystals showed least variability in performance, whereas the PET crystals demonstrated the most.
An X-Ray Spectrometer for Pixel Analysis of Art Objects
Authors: Mantler M. , Schreiner M. , Weber F. , Ebner R. , Mairinger F.
Published: March 2019

An x-ray spectrometer has been designed for pixel by pixel analysis along lines or across selected areas of paintings and other art-objects. Characteristic technical data are: 0.8mm2 pixel size, 800mm (vert.) by 1000mm (horiz.) by 200mm (perpendicularly to object) motion distances, ±20μm precision in positioning the system, 2x3m maximum object size (mounted vertically); 2.8kW x-ray tube; Si(Li)detector. PC's are used for instrument control and new, complex data evaluation software.
X-Spectrum Determination Applied to Flash Radiography
Authors: Le dain Loïc , Dinten Jean-Marc
Published: March 2019

We propose a method, by absorption [1,2,3,4], of determination of the X-ray spectrum emitted by a flash X-ray radiography generator. This approach leads to an ill posed inverse problem very sensitive to the measures precision.

We improve the robustness of the method by introduction of a smoothness constraint on the X-ray spectrum to reconstruct. We also propose an automatic choice of the weight between the measurement and the constraint by using a cross-validation technique.

We present an application on an unusual flash X-ray radiography generator - i.e. 75 ns of duration pulse, 6.5 MeV of maximum energy, 350 Rad for dose - for which an instrument of direct measure has not yet been found.
Evaluation of a Combined Transmission and Scattering Approach to Composition Imaging of Industrial Samples
Authors: Prettyraan T. H. , Gardner R. P. , Russ J. C. , Verghese K.
Published: March 2019

Composition imaging of industrial samples has been reported using dual energy and multiple energy transmission computed tomography [1,2]. The simplest approach utilizes monoenergetic sources to obtain tomographs of a sample at two different energies. Each tomograph represents the linear attenuation coefficient distribution of the sample at the given source energy.
Gamma Ray and X-Ray Imaging Studies of the Location and Shape of the Melt-Solid Interface During Bridgman Growth of Germanium and Lead-Tin-Telluride
Authors: Simchick R. T. , Sorokach S. , Fripp A. L. , Debnam W. J. , Berry R. F. , Barber P. G.
Published: March 2019

The success of new electronic materials has been due in part to the development of procedures that produce semiconductors of sufficient purity and perfection. These materials have been grown from the gas phase, solution, and melts. The Bridgman technique is one way semiconductor crystals are grown from the melt. In such furnaces the semiconductor material is usually sealed in an ampoule made of quartz or other suitable material, placed inside the tubular furnace, and heated to completely melt the sample. The ampoule with the molten material is slowly removed from the furnace by one of three ways.
The Role of X-ray Fluorescence in a Modern Geochemical Laboratory*
Authors: Taggart Joseph E.
Published: March 2019

Modern geoehemical studies have evolved significantly over the last few decades. Exploration programs have become more ambitious and have expanded to cover entire nations, requiring many tens of thousands of analyses. With the increased demand for chemical analyses, many laboratories have opted for automated, rapid, high-technology instruments, rather than adding a larger number of skilled personnel. It is not clear whether the advance of automated instrumentation in the laboratory predated the demand for large numbers of analyses, but with the increased availability of computers, even basic research problems have come to employ larger numbers of samples. Because modern geochemical laboratories can seldom have all new analytical equipment, from the beginning it is clear that priorities must be assigned and choices made when selecting each new instrument.
Feasibility Studies of X-ray Fluorescence as a Method for the In Vivo Determination of Platinum and Other Heavy Metals
Authors: Dutton J. , Evans C. J. , Samat S. B. , Morgan W. D. , Sivyer A.
Published: March 2019

There has recently been growing interest in various atomic and nuclear techniques for the measurement of elements in the body. This has arisen through the realisation that (a) clinically-important amounts of toxic elements can be absorbed as a result of low-level environmental exposure, and (b) important information about the nutritional status of a patient can be obtained from measurements of major body elements. Where such information can be obtained by taking samples, a very wide range of analytical techniques is available, some capable of a sensitivity measured in parts-per-billion. Sampling is not possible, however, when the whole-body content (e.g. of nitrogen) is required, and is clinically undesirable when the element in question is concentrated in particular organs, for example as lead accumulates in the bones, and cadmium and many other toxic elements accumulate in the kidneys. It is in such cases that the various in vivo techniques are particularly important.
An XRF Method for the Analysis of Atmospheric Aerosol and Vehicular Particulate Deposits on Filters
Authors: Rokosz M. J. , Artz B. E. , Belitz R. K.
Published: March 2019

X-ray fluorescence (XRF) was required to analyze vehicle exhaust particulate samples deposited on filters to determine the trace element content of the emissions. These samples were collected as part of a study to assess the role of vehicular particulate emissions in the Denver “Brown Cloud” problem. This study was an adjunct to an earlier study of vehicular gaseous emissions at high and low altitudes. The earlier program involved complete certification testing of a fleet of twenty five (25) 1970, non-catalyst vehicles but did not include analysis of exhaust particulate emissions. Consequently, a subset of the original vehicles was selected for retesting at high and low altitudes. A complete analysis was necessary to compare the ratio of particulate carbon to lead in the vehicle particulate emissions at the Denver test site.
Results of a Round Robin Study of Systematic Errors Found in Routine X-ray Diffraction Raw Data
Authors: Schreiner Walter N. , Fawcett Tim
Published: March 2019

The JCFDS-ICDD based in Swarthmore, PA maintains and distributes a database of powder diffraction data. This database is widely used throughout the world by x-ray analytical laboratories for crystalline phase identification. It is the charter of that organization to update, expand and upgrade the quality of data in the database. As this work is carried out, the database is made available on an annual basis at a fee Commensurate with the committee's operation as a self-sustaining, non-profit organization.
An X-ray Diffraction Method for the Determination of Temperatures in Coke Reactions
Authors: Johnson Jack L. , Katz Seymour
Published: March 2019

Information about the conditions and reactions in a foundry cupola is essential to understand the thermochemistry of a cupola and thus improve its efficiency. A potential source of such information is coke taken from inside an operating cupola. In the region of the cupola that extends from the melt zone to the taphole, coke is directly involved in important chemical processes such as combustion, gasification, slag formation, iron sulfurization, carbon pickup, and oxide reduction. Coke is also suspected of being involved in the transport of silicon to the liquid iron. Each of these processes produces characteristic physical and/or chemical changes in the coke, making it possible to extract information about the processes from an examination of coke pieces taken from within an operating cupola. A program to study such coke samples is in progress. To effectively interpret these data it is necessary to know the temperature history of the coke being examined, especially the maximum temperature attained by the coke piece in the cupola.
Recent Developments and Results in Total Reflection X-ray Fluorescence Analysis
Authors: Wobrauschek Peter , Kregsamer Peter , Streli Christina , Aiginger Hannes
Published: March 2019

In the last years Total Reflection X-Ray Fluorescence spectroscopy (TXRF) has shown to be an analytical technique for trace element analysis as well as surface quality control. Detection limits in the range of pg or ng/g (ppb) level in concentration values of aqueous solutions or 1011 -109 atoms/cm2 are achieved with new excitation sources. The range of detectable elements has been extended to low and high 2 elements. Instrumental developments and results of the Atominstitut as well as from some other working groups are presented.
Phosphorus Determination in Borophosphosilicate or Phosphosilicate Glass Films on a Si Wafer by Wavelength Dispersive X-ray Spectroscopy
Authors: Levine H. S. , Higgins K. L.
Published: March 2019

Films of borophosphosilicate glass (BPSG) or phosphosilicate glass (PSG) are deposited on single crystal Si (100) wafers (typically 4 to 6 inches in diameter) by chemical vapor deposition processes during the fabrication of radiation-hardened microcircuits. These films act as insulator and as passivation layers. Since the P content of the glass layer is critical because of fluidity and corrosion problems, careful certification is required. The certification analysis has been accomplished here previously by empirical energy dispersive (ED) X-ray fluorescence (XRF) methods which use a set of expensive and fragile PSG wafer calibration standards. The results obtained were uncertain and the standards were sometimes broken.
Strategies for Preferred Orientation Corrections in Xray Powder Diffraction Using Line Intensity Ratios
Authors: O'Connor B.H. , Li D.Y. , Sitepu H.
Published: March 2019

Li et al (1990) reported experiments with gibbsite powder specimens on the use of Rietveld pattern-fitting, involving the March preferred orientation model, to characterise preferred orientation according to the March r parameter. It was shown that intensity corrections may be applied with the March r parameter derived from Rietveld analysis or with the related line intensity ratio MR which is sensitive to preferred orientation. The present paper reports an analytic expression involving r and MR which has proved highly reliable for the correction of preferred orientation bias in quantitative phase analysis of gibbsite. Similar expressions may be readily derived for other materials for which the March model is appropriate. Therefore the line ratio approach has considerable potential for rapid correction of intensities for preferred orientation.
Residual Strains in Al2O3/SiC (Whisker) Composite from 25-1000°C
Authors: Ballard Benjamin , Predecki Paul , Hubbard Camden
Published: March 2019

Residual strains in a hot-pressed α-Al2O3/25 wt % β-SiC (whisker) composite were determined at temperatures from 25 to 1000°C in 250°C increments. The data collected from the (146) reflections of Al2O3 and the (511+333) reflections of SiC whiskers indicates that residual strains in both phases decrease linearly with temperature; the composite's extrapolated zero-strain temperature is determined to be 1471°C and comparable to the value ~1350 °C obtained by Majumdar et al. from neutron data. The lattice thermal expansion of the whiskers agrees well with literature, data for the monolithic β-SiC form.
Applications of X-ray Diffraction Crystallite Size/Strain Analysis to Seismosaurus Dinosaur Bone
Authors: Chipera Steve J. , Bish David L.
Published: March 2019

Recently, the remains of a giant Cretaceous Sauropod (~150 My old) were discovered in the Morrison Formation west of Albuquerque, New Mexico. This dinosaur, tentatively named Seismosaurus, was found in an exceptional state of preservation. Although it has been known since the 180Q's that fossilized bone is often composed of the mineral apatite, very few studies have been conducted to characterize farther the fossilized material. In an effort to gain insight into the state of preservation and Hie processes occurring in the bone since deposition, apatite in bone from Seismosaurus was compared with that from a contemporary elk from the Jemez Mountains, New Mexico, and with well-crystallized mineral apatite using X-ray powder diffraction and profile analysis techniques. Crystallite size/strain analyses were conducted using the Scherrer equation, the Warren-Averbaca and single-line methods, and the Rietveld method using the program GSAS. Heating the contemporary elk bone produced a decrease in the full-width-at-half-maximum (FWHM) of the reflections in the diffraction pattern. This decrease in FWHM is due to a decrease in microstrain along with a minor increase in crystallite size. Results from crystallite size/strain analysis show that both Seismosaurus and contemporary elk bone crystallites are elongate parallel to the c-axis. However, Seismosaurus bone crystallites are larger (-20-65 nm) with less strain than the contemporary elk bone crystallites (-8-20 nm), suggesting that if elk bone is an appropriate analog, then Seismosaurus bone must have undergone recrystallization.
The Effect of Satellite Lines from the X-ray Source on X-ray Diffraction Peaks
Authors: Briden Frank E. , Natschke David F.
Published: March 2019

We have been using crystallite size and strain data obtained from x-ray diffraction (XRD) peak profile analysis to predict the reactivity of solid calcium hydroxide sorbent with acid gases in combustion streams. The development of the method for relating reactivity to crystallite size and strain parameters obtained by the Warren-Averbach technique has been reported by Briden and Natschke and Briden.

The software used for the calculations requires that the XRD peak profile be corrected with a distribution function before application in the Warren-Averbach analysis. The reason for this according to the software developer, Gerhard Zorn, of the Siemens Munich Laboratory, is that he has shown that contributions to the profile from alien peaks and random noise can have serious effects on the Warren-Averbach analysis. The fitting of (he experimental XRD peak with a distribution function provides an effective means for filtering out both contributions.
Double-Crystal X-ray Diffraction Studies of Si ion-Implanted and Pulsed Laser-Annealed GaAs
Authors: Adams P. M. , Knudsen J. F. , Bowman R. C.
Published: March 2019

Ion-implantation has many applications in the fabrication and processing of microelectronic devices from semiconductors, but thermal treatments are required to remove defects produced by the implant and to electrically activate dopants. Recently, pulsed laser annealing has been used to activate surface layers of GaAs that have been heavily doped with 28Si+ by ion implantation, and carrier concentrations of > 1 x 1019 cm-3 have been achieved (Ref. 1). Double-crystal x-ray diffraction techniques are very sensitive to strains and defects in single crystals and provide a means for characterizing and quantifying the damage produced by ion-implantation and the subsequent relief of damage by pulsed laser annealing.
X-ray Study on Fatigue Fracture Surfaces of Aluminum Alloy Reinforced with Silicon Carbide Whiskers
Authors: Funaki Katsuyuki , Nanayama Yukio , Ichimaru Yoshiji , Hirose Yukio , Tanaka Keisuke
Published: March 2019

X-ray fractography is a new method which utilizes X-ray diffraction observation of the fracture surface for the analysis of micromechanisms and mechanics of fracture. The line broadening of X-ray diffraction profiles and the residual stress left on the surface are two of the important parameters.
Recent Advances in X-Ray Laser Research
Authors: Elton Raymond C.
Published: March 2019

The x-ray laser has recently been described (1) as a potentially attractive tool for chemical analysis, both as an improved source for ESCA and also for radiochemistry. The intensity (∼1016 photons/pulse) and associated short exposure time (10-15-10-12 sec) promised are the most attractive features, as is the narrow line width (0.1-0.01 eV). [Such photon fluxes would be equivalent to 1-12 days of exposure with projected electron storage rings (1).] Improved resolution in chemical shift determinations by ESCA are promised as are observations of short-lived excited states and rapid reaction rates in highly-concentrated chemical species. For general utility and optimum analytical capabilities, a photon energy in the 1 keV range from a 10 Å laser would be adequate and is projected (2) to be within the realm of presently conceived technology. Neither a high degree of collimation nor coherence is considered essential although the latter is associated with particularly narrow lines, so that plasma-type noncavity amplified spontaneous emission (ASE) devices (2) will prove adequate.