Emission-concentration proportionality Is one of the main features of electronprobe mlcroanalysis. It can be interpreted by taking simultaneously Into account the Z/A factor of Webster's law of deceleration and the variation with atomic number of the backscattering ratio. The baclcscattering ratio itself can be deduced approximately from experimental distribution curves of thecharacteristicemisslonjejqpertments on copper-gold alloys show good agreement with the theoretical predictions. An important practical consequence is that regulation of the electron beam falling onto the specimen leads to better results than regulation of the current passing through it. The different corrections are discussed, with special reference to the fluorescence induced by the general continuous spectrum. The case of insulating materials is considered separately; preliminary experiments seem to show that their behavior is not essentially different from that of conducting materials.

I report the experimental setup to obtain an x-ray beam from germanium monocrystal of unusually small angle of vertical divergence of the order of 2 sec. of arc without using any collimator. The production and the properties of the highly collimated beam of x-ray will be described. A rectangular piece of germanium 1” × 1” and of thickness 0.5 mm has been cut with specific orientation of crystallographic planes (111) and (110). The 1” × 1” surface is parallel to (111) planes and the surface of one edge is parallel to (110) planes suitable for Borrmann channelling via (220) planes.

This paper describes a set of interactive computer programs written in FORTRAN IV and implemented on a POP 11/34 equipped with RLO-2 ten Mbyte discs and an RSX-11M operating system to assist in x-ray diffraction phase analysis. The packing of the data base will be described along with the various interactive programs that access it. The search/match package is designed more as a set of aids for the diffractionist rather than as a single totally automated search/match program, the procedure adapted by many of the xray diffraction (XRD) equipment manufacturers. The approach taken allows the analyst to direct the analysis procedure by utilizing different search/match programs or specifying various options within a given program.

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.

Spectrographic analysis of light elements by soft and ultrasoft fluorescent x-rays has become a useful technique for many applications of elemental analysis, using single crystals, soap multilayers and a combination of total reflection and filtering.

Instead of the wavelength dispersive method based on Bragg reflection which provides high resolution combined with low reflecting intensity, monochromatization combining total reflection by a selected mirror and an appropriate filter offered an alternative approach in order to increase measurable intensity with reasonable spectral resolution.

Recently, the use of synthetic multilayers, which are prepared by sputter/evaporation techniques, has been introduced for the detection of soft and ultrasoft x-rays. Studies on the use of these new wavelength dispersing devices have been conducted and it has been found that the reflectivity of these devices is very high compared with single crystals and soap multilayers and that their resolving power is fairly good.

Total-reflection X-ray fluorescence spectrometry, abbreviated as TXRF, is known for its high sensitivity down to the low pg-level or sub-ppb level, respectively, and its wide dynamic range of about three to four orders of magnitude (Yoneda and Horiuchi, 1971, Wobrauschek and Aiginger, 1980; Knoth and Schwenke, 1978 and 1980, Aiginger and Wobrausohek, 1985, Michaelis et al., 1985, Prange, 1987). Meanwhile several laboratories have purchased commercially available TXRF spectrometers and have started to report favourable about this technique. Applications have been reported from various disciplines: These are estuarine and marine water quality management and research, air pollution studies, mineralogical investigations, biology and medicine (Prange, 1987, Prange et al, 1985; Prange and Kremling, 1985, Prange et al., 1987, Stöβel and Prange, 1985, Michaelis, 1986, Ketelsen and Knöchel, 1985, Leland et al., 1987, von Bohlen et al., 1987, Junge et al., 1983, Hentschke et al., 1985, Hentschke et al., 1985, Gerwinski and Goetz, 1987, von Bohlen et al., 1987), In spite of its close kinship to conventional EDXRF , TXRF is quite different with respect to operation and performance and provides complementary capabilities.

X-ray diffraction analyses were applied to various pure nickel substrates while exposing them to oxygen at temperatures up to 800 °C. Coefficients of thermal expansion (CTE) were calculated from lattice parameters for both the nickel and the growing surface oxides. Behaviors more complex than the case for single phase bulk solids were observed due, in part, to oxidationinduced strains. The CTE values for such dynamic composite systems are not the same as those for the bulk solids. Thus, for example, the CTE values were found to be dependent on substrate metal thickness. In addition, discontinuities in the CTE's of both nickel and NiO occurred at or near their respective second order phase change temperatures.

A formalism which was proposed by Ruppersberg (1992) for a self consistent evaluation of stress gradients in the case of strongly varying σ33(T) stresses is applied for studying the variation of the stress components with distance z from the irradiated surface of a ground hardened steel plate.

X-ray diffraction and electron microprobe analysis were used in combination to identify reaction phases that formed on the surfaces of low-carbon steel specimens reacted with a 75% basalt-25% bentonite mixture and anion-doped water in sealed pressure vessels at 100°C and 250°C. Reaction phases on specimen surfaces and in adhering geologic material were identified by conventional X-ray diffraction scans of entire specimens with intact reaction layers. Comparison of results from adhering geologic material and scans of selectively removed layers allowed establishment of approximate reaction gradients in the adhering packing material. Electron microprobe analysis of specimens in cross-section provided quantitative chemical analyses of adhering reaction phases, and identification of reaction layer composition gradients and thicknesses. Magnetite formed on the surface of specimens reacted at 250°C for 4 weeks. Iron-enriched clay was also observed on specimen surfaces and in the adjacent basalt-bentonite mixture. The 100°C experiments yielded surface films of a siderite-structure phase, (Fe,Ca,Mn)CO3, that were not observed in previous experiments with synthetic ground-water. Less extensive iron enrichment of the adjacent clays compared to that seen in the 250°C experiments was observed. The siderite-structure phase generally formed when no carbonate ion was present in the initial solution, implying dissolution of impurity calcite in the bentonite as the controlling factor in the reaction. The results demonstrate the utility of combining X-ray diffraction and electron microprobe analysis for characterization of reaction phases on alloys reacted with complex geologic materials.

Due to the current high interest in characterizing epitaxially deposited thin films required by the electronics industry as well as the increased attention in elucidating reactions between solid surfaces and the environment (e.g., corrosion), investigators have increased their efforts in developing X-ray procedures for analyzing films and surfaces less than 2 μm thick. For example, an entire session of the 1985 Denver Conference on Applications of X-ray Analysis was devoted to this subject and an excellent review of X-ray diffraction techniques for characterizing thin films was recently published by Segmuller (1). Specific techniques include grazing incidence diffraction (2, 3), double crystal diffraction (3), and the use of the Seemann-Bohlin focusing geometry (4, 5).

Since the development of the first practical electron probe microanalyzer by Castaing and Guinier in 1951, approximately 14 such instruments have been placed in operation throughout the world and at least 15 more are under construction. All of the existing instruments contain the following basic components: (1) An electron beam system, (2) a movable specimen stage, (3) a means for viewing the surface of the specimen, and (4) an X-ray analyzer. The integration of these components into a practical instrument requires certain compromises in the performance capability of the instrument. A critical evaluation of the various approaches to this problem is given and a new electron objective lens is described which results in fewer restrictions on the over-all performance. The basic design of an instrument employing this lens, which will be manufactured by the Applied Research Laboratories, is discussed.

Rietveld X-ray powder diffraction (XRD) and uniaxial stress measurement procedures are being evaluated as a means of correlating the crystalline structure properties of zinc-nickel electroplate with observed plating properties. The study is being performed on a suite of six samples of varying composition (6 to 20%Ni) electrodeposited on mild steel. Rietveld refinement of the XRD data (Rietveld, 1969) has been performed on a specially prepared ingot (9%Ni:91%Zn) to determine the structural parameters and relative abundances for the γ(Ni4Zn22), δ(Ni3Zn22) and η(Zn) phases which could possibly be present in the electroplate. Relative phase abundances were verified by Atomic Absorption Spectrometry (AAS) and electron probe microanalysis (EPMA) image mapping techniques.

The structural parameters for the ingot zinc-nickel phases were subsequently used as initial parameters in Rietveld calculations for the six electroplate samples. Structure refinement of the electroplate XRD data was hampered by extremely high preferred orientation and the corresponding lack of quality diffraction peaks. However, Rietveld refinements produced accurate cell dimensions (which correlate linearly with nickel composition), a means of quantifying the degree of preferred orientation, and crystalline phase verification. For residual stress determination, d-sin2ψ plots were produced for each electroplate sample. The plots were found to be linear for Ni < 12%, allowing calculation of residual stress, and distinctly curved for Ni > 12%.

The use of glancing angles of incidence enables X-ray Absorption Spectroscopy to be measured as a function of depth from the surface of a material into the bulk. As x-rays rather than photoelectrons are detected, a UHV environment is not required and instead surfaces and interfaces can be examined under realistic operational conditions. Whilst the reflected beam carries the fine structure of concentrated species in the imaginary part of the refractive index, this is obscured by the contribution from the real part for angles greater than ϕc, the critical angle for total external reflection. Measuring the x-ray fluorescence offers more flexibility, particularly for dilute systems. The use of synchrotron radiation in conjunction with a multi-element Solid State Detector enables impurity loadings down to a few 1019 cm-3 to be measured which for ion implants is equivalent to around half-monolayer coverage at the surface. This sensitivity makes it practical to examine impurities in semiconductors at realistic dopant levels.

The Fourier analysis of the broadened profiles in a powder pattern allows the determination of the effective particle or domain size and the microstrains within each domain in polycrystalline materials. In order to apply this method to the diffraction patterns of thin films and coatings, deposited on crystalline or amorphous substrates, special diffraction techniques must be employed for the registration of the relatively weak intensities. The fitting of the experimental profiles to pseudo-Voigt functions permits the recovery of the peak tails and a precise determination of the background. The positions of the peak maxima or centroids yield information about any compositional variations, and about the occurrence of stacking faults and residual stresses in thin films and coatings.

Ten compounds are found in the Ba0-Y203-CuOx system. High temperature (≈950-1000°C) phases identified as Ba4Y2O7 , Ba2Y2O5 , Ba3Y4O9 , BaY2O4 , Y2Cu2O5 , BaCuO2+x, Ba3YCu2OZ BaY2Cu05 and BazYCu306+x are formed in this temperature range. In addition, a new compound with composition of 2BaO:CuO, which possibly has a melting point below 950°C, was prepared at 850°C. A summary o£ the crystallographic data of these 10 phases is given. In particular, results of x-ray studies pertaining to four compounds, BazYCu306+x, which is currently the most promising high To' superconductor material, Ba2Cu03 , BaY2Cu05 , and Ba3YCu20Z are reviewed.

Texture (of a polycrystalline sample) means the orientation distribution of the many crystallites in the sample with respect to a coordinate system on the sample, for example the rolling direction. Texture is responsible for many macroscopic properties of materials, for example in metals and alloys in the process of rolling or hot-pressing. It carries importance in many everyday production processes. Also in areas of geological science the texture of the sample, e.g. of the rocks should be known in order to explain geological processes.

Revised tables of x-ray mass attenuation and absorption cross sections have been prepared for the elements with atomic numbers one to 94 at selected wavelengths of interest to spectroscopists, microprobe users, diffraction workers, etc. The tables are derived from an x-ray cross section compilation to be published during the summer of 1971. The new compilation is a revision of a previous work and provides photoelectric, coherent scattering, incoherent scattering, absorption component of incoherent scattering and total attenuation cross sections for 94 elements for the photon energy range 0.1 keV to 1 MeV (0.0124 Å to 124 Å). The cross sections for energies greater than 1 keV (12.4 Å) were determined from experimental attenuation data and theoretical scattering cross sections calculated using form factors and incoherent scattering functions based on a relativistic self consistent field method. For hydrogen, the photoelectric absorption cross sections were calculated exactly. Least squares procedures were used to interpolate and extrapolate for elements and photon energies where no experimental data were found. Cross sections for the energy range 0.1 keV to 1 keV (12.4 Å to 124 Å) were calculated using nonrelativistic, single electron, self-consistent field theory with Herman-Skillman bound state wavefunctions, A brief description is given of the assumptions and methods used in preparing the revised compilation, and estimated uncertainties in the cross section are reported. Examples illustrating agreement between tabulated values and experimental data are given and a comparison is made with values taken from earlier x-ray cross section compilations.

The oscillation from a linear relation in the 20 vs. sin2ψ diagram has been a most important problem in X-ray stress measurement. There are, therefore, a number of papers concerned with the X-ray elastic constant, lattice strains under stresses and evaluation of stresses of textured materials.

The purpose of the present study is to analyze the three-dimensional orientation distribution of steel sheets by means of the Vector method proposed by Ruer and Baro, and to calculate the elastic modulus of textured sheets by means of a finite element method (FEM) using the three-dimensional orientation distribution, and then to calculate the strain/stress ratios vs. the directions defined by the angles between the specimen normal and the normal to the diffracting planes.

The effect of temperature on nucleation and growth of Ti3Al precipitates in two Ti-Al alloys was determined using sensitive X-ray diffraction techniques. The X-ray peaks arising from the ordered Ti3Al phase were compared with the fundamental peaks of the matrix. Peak broadening due to particle size resulted from the small Ti3Al precipitates and this was analysed using Fourier methods to determine a mean particle size and particle size distribution. The two alloys used for this investigation were Ti-8.5 wt.% Al and Ti-8%Al-1%Mo-1%V (8-1-1) alloy. The precipitate size in Ti-8.5 wt% Al was considerably more dependent on temperature than the precipitate size in 8-1-1 alloy, achieving a size of 190Å after 20 hrs at 650°C. The solvus temperature for precipitation was the same for both alloys, vis, 675°C to 700°C. These results compare favorably with transmission electron microscopy of thin foils prepared from the same samples.