A new ESCA (electron spectroscopy for chemical analysis) instrument has been developed to provide high sensitivity and efficient operation for laboratory analysis of composition and chemical bonding in very thin surface layers of solid samples. High sensitivity is achieved by means of the high-intensity, efficient X-ray source described by Davies and Herglotz at the 1968 Denver X-Ray Conference, in combination with the new electron energy analyzer described by Lee at the 1972 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. A sample chamber designed to provide for rapid introduction and replacement of samples has adequate facilities for various sample treatments and conditioning followed immediafely by ESCA analysis of the sample.

Examples of application are presented, demonstrating the sensitivity and resolution achievable with this instrument. Its usefulness in trace surface analysis is shown and some “chemical shifts” measured by the instrument are compared with those obtained by X-ray spectroscopy.

An unexplained anomalous sin2ψ split in x-ray stress measurements has consistently resulted from the use of Cr Kα radiation with nickel and austenitic stainless steels. Both, materials have diffraction peaks at low back-reflection angles for this radiation (nickel: 20 ⋍ 134°, austenitic stainless steel: 20 ⋍ 128°). The anomalous split is not evident when the measurements are made using Cr Kβ radiation, In an attempt to explain the errors produced by the Cr Kα radiation, focusing circle effects were analyzed and compared to experimental measurements made with both Cr Kα and Cr Kβ radiation on nickel-based samples,

Synchrotron Radiation Induced X-ray Fluorescence analysis was successfully applied to the analyses of meteorites, archaeological objects and animal tissues. Electronic states of Fe and Ti in chondrules of chondrites were clarified by micro-XANES to be Fe2+ and Ti4+. Ancient iron implement (B.C. 3c A.D. 3c) with zoning of rusts was characterized by micro-XANES. Two dimensional chemical state analyses of the sample were made by selective excitation of iron. Trace element analyses of Cu, Zn, Se, and Hg in the brain and kidney of rat, mouse, and guinea pig dosed with alkyl mercury and/or Se were made from a view point of mercury intoxication. Strong correlation between Hg and Cu, Zn, Se was observed by the correlation analysis of the elemental distributions. The XRF imaging also disclosed decrease of Cu and Zn level in cancerous tissues of human kidney compared with normal ones.

Advantages of Synchrotron Radiation (SR) as an X-ray source of X-ray Fluorescence (XRF) Analysis have been demonstrated by many pioneering researchers. The advantages include wavelength tunability, high intensity and high resolution, which allow us to carry out nondestructive multielemental analysis of trace elements. However, practical application of the SR-XRF is still limited in numbers. The authors expected that the application of SR-XRF is most promising in the fields of archaeological objects, geological samples, and biological samples and started the present research projects in 1987. Now we have established the analytical procedures of these samples by SR-XRF that we report a part of our results, which so far we obtained from the analyses of geological samples, archaeological objects and biological samples.

The techniques of chemical state analysis used in this study are based on the following two approaches: one is XANES (X-ray absorption Near Edge Structure) and the other is SIXES (Selectively Induced X-ray Emission Spectroscopy). It is well known that the former technique together with EXAFS has been developed rapidly with the development of intense SR beams. SIXES was recently established by Sakurai et al. It enables us to carry out chemical state mapping by X-ray fluorescence using absorption edge shifts. This method was first applied to practical problems in this study.

Thermal analyses of samples of thorium dicarbide in equilibrium with graphite show arrests which indicate phase transitions at 1427 ± 21°C arid 1481 ± 28°C. These thermal effects have been observed on heating and cooling both in standard thermal analysis and in differential thermal analysis using graphite as a reference material. The microstructure of thorium dicarbide samples shows the characteristic “herringbone” pattern of a material which has undergone a martensitic-type transition.

A high-temperature X-ray investigation has revealed that the observed thermal arrests correspond to erystallographic transformations. The monodinic modification found at room temperature is stable to 1427°C, at which temperature a tetragonal modification with a0 = 4.235 ± 0.002Å and c0 = 5.408 ± 0.002Å is formed. At 1481°C, the tetragonal is transformed to cubic with a0 = 5.809 ± 0.002 Å. The best agreement between observed and calculated intensities has been obtained with C-C units of 1.5-Å assumed bond length in space groups P42/mmc and Pa3 for the tetragonal and cubic modifications, respectively.

Plastic deformation of metals produces a state characterized by the presence of residual elastic strains, small domains which diffract X-rays coherently, and often stacking faults; these effects may be studied with X-ray diffraction techniques. Changes in the lattice parameter, shifts in the relative positions of diffraction lines, and the broadening of diffraction lines were used to study the state of coldwork resulting in Cu-6.6 at.%Si-1.2 at.%Mn after deformation by filing, wiredrawing, and uniaxial tension at room temperature.

Both filing and wire-drawing produce large root-mean-square strains and stacking faults, whereas deformation by tension up to 22% extension fails to produce any clear evidence of faulting or root-mean-square strains. Tensile deformation causes fragmentation of coherent domains to an average dimension of 250 Å after 22% extension, and results in a radial, tensile, residual macrostrain arising from a smaller rate of work hardening in the surface layers than in the interior. Wire drawing also results in a residual macrostrain system. Deformation appears to enhance diffusion and promote solute clustering at room temperature.

Two-dimensional detectors utilized in x-ray diffraction studies are described. Film, image intensifier/CCD camera, two-dimensional position-sensitive area, and photostimulable storage phosphor detectors are compared. The storage phosphor detector was found to be well suited for analysis of oriented semicrystalline polyester films. Quantitation of polymer orientation was determined using the Hermans orientation distribution function.

Total Reflection X-ray Fluorescence Analysis (TXRF) has been proved to be well suited for the energy dispersive analysis of light elements, as B, C, N, O, F, Na, Mg,.,. using a special spectrometer. It is equipped with a Ge(HP) detector offering a sufficient detection efficiency from 180 eV upwards. The obtainable detection limits especially of the light elements are mainly influenced by the excitation source, which should provide a large number of photons with an energy near the K-absorption edge of these elements (from 200 eV upwards). Commercially available X-ray tubes do not offer characteristic X-rays in that range. In former experiments a windowless X-ray tube was built to prevent the low energy X-rays from being attenuated in the Be window. Experiments have been performed using Cu as anode material.

The electroplating of Cr has been an important industrial process for cutting tools, press machines and molds for casting. In spite of these, quite a few problems remain unsolved regarding the basic property. It is important to know the mechanical characteristics of Cr electroplated layers.

In the present paper, the first part deals with the measurement of mechanical Young's modulus of Cr electroplated layers. The X-ray method was successfully applied to measure the X-ray Young's modulus and the residual stress on the Cr electroplated surface layer.

Modern powder diffraction employing computer-controlled diffractometers now allows quantitative analytical methods to use the whole diffraction trace rather then only individual peaks. Two such methods are in common use the Rietveld method which refines the crystal structures of the component phases as part of the matching calculation, and the patternfitting method which uses reference patterns from a database. Potential accuracies of these methods seems to be around 1 % absolute. The most severe limitation on the potential accuracy of these methods is particle statistics, which has been reviewed in considerable detail.

Rat tail tendons were fixed in 4% formaldehyde at 250 g tension, soaked in nearly saturated solution of the amides involved, and dried while still under tension. X-ray diffraction patterns, taken with rotation around the collagen fiber axis, showed well-defined layer lines of the amide and usually substantial expansion of the collagen equatorial spacing.

The layer lines on collagen, in two cases on abnormal or polymorphic axes, are clustered around the number 4.86 ± 0.33 Å, or a figure twice this, implying the presence of a repeating hydro gen-bond accepting group such as the carbonyl group at this interval. The prominent collagen layer line at 9.4 Å is approximately double this interval.

Measurements of x-rays emitted by hot plasmas provide a powerful diagnostic method of determining important plasma parameters and suggest certain types of plasmas as possibly useful x-ray sources. Instrumentation to accomplish these measurements for various types of plasmas are reviewed. State-of-the-art x-ray spectrometers, calorimeters, and source-imaging devices, designed especially for plasmas generated by focused, nanosecond laser pulses are described. Possibilities of time-resolved measurements on such short-lived plasmas are discussed.

The electron density distribution maps for CaF2 and TiO2 (rutile) were obtained from profile fitting of powder diffraction data by a Maximum Entropy Method (MEM) analysis. The resultant electron density maps show clearly the nature of the chemical bonding. In order to interpret the results, the nuclear density distribution was also obtained for rutile from powder neutron diffraction data. In the electron density map for rutile obtained by HEM analysis from the X-ray data, both apical and equatorial bonding can be seen. On the other hand, the nuclear density of rutile Is very simple and shows the thermal vibration of nuclei.

Silicon carbide and 6061 aluminum alloy possess very different thermalexpansion coefficients; 3-3 and 22.5.10-6K-1, respectively. Thus, one expects large internal strains and stresses in these composites because the two constituents form interfacial bonds at high temperatures and are cooled to ambient temperatures. From a simple elastic model, one expects a hydrostatic tensile stress in the aluminum matrix and a-hydrostatic compressive stress in the silicon-carbide particles. Using conventional diffraction geometry, using Cu Kα radiation, we studied three surfaces of a plate specimen. For both phases, we determined the unit-cell dimensions for two situations: unmixed and mixed in the final composite. The silicon-carbide particles showed a compressive stress and the aluminum matrix a tensile stress, seventy-five percent of the yield strength. Measurements show that both stress tensors are approximately hydrostatic.

In order to reveal the mechanism of the negative c-axis expansion in cordierite (4 MgO 4 Al2O3 10 SiO2), the thermal expansion of cordierite containing small amounts of Cs, Li, B, Ge, Sc and Ni-cations was investigated by time-of-flight neutron diffraction at temperatures between 22 and 750°C. The samples were prepared by melting the constituent oxides followed by quenching and devitrification to obtain the hexagonal form (Indialite). Using the neutron powder diffraction data, the atom positions in the space group P6/mcc were refined by Rietveld least squares analyses.

The expansion behavior of the cordierite structure could be explained in terms of the various kinds of constraints and the interatomic bond strengths of the structure. It was found that cordierite doped with Cs-cations shows the largest volume expansion, followed by the Li-doped sample. So-doped cordierite has the lowest volume expansion. All cordierite samples show positive expansion along the a-axis and negative expansion along the c-axis, except the Cs-doped sample which has positive expansion in both directions.

Metallic filaments with sub-micrometer diameters have recently been fabricated using novel materials fabrication techniques at NRL. The specimens are enshrouded in a glass sheath and all efforts to obtain structural information from these samples with conventional x-ray sources have been negative. By using synchrotron radiation on a wiggler beam line, x-ray diffraction data have been obtained from samples with diameters of 0.22, 0.09, 0.07, and 0.04 μm. The two thicker samples were found to be single crystals with a structure consistent with that of normal Bi. Single crystal diffraction peaks obtained from the 0.07 μm sample are incompatible with the Bi-1 or any other known structure of Bi. We have provisionally identified this as Bi-X.

It is necessary to know the orientation of thin surface layers for the electronic industry as well as for different studies on interphases (epitaxy, topotaxy, phase transformation, reactivity of solids).

It is difficult to obtain information with a conventional Schulz goniometer (Bragg-Brentano geometry) because of the insufficient amount of diffracting material.

Calculations carried out to investigate the van Cittert iterative deconvolution method and the effects of random noise and truncation errors on its convergence behavior are presented. Gaussian functions are used for "both the true function W and the system, response function A. The model "observed" function S is generated from W and A. Both rms differences between the result of n iterations Wn and the true function, and between Wn*A and S are used to measure convergence. The effects of introducing errors can be measured against standards set by the convergence without such errors. These "no-error" calculations make use of true functions with widths from 2.0 to 0.67 times the response function width. The effects of random noise are investigated by adding noise to W*A before deconvolution. A small amount of random noise initially added builds up rapidly in amplitude during the iterative process and eventually dominates the rms difference calculations. To suppress the effects of random noise build-up; smoothing techniques are applied, the best of which involved smoothing both the noisy observed function, S, and the system response function, A, before deconvolution. The smoothing operation is thus taken as part of the measurement and. the divergence resulting from, the noise build-up is avoided. The results depend strongly upon, the -width of the smoothing function. Uhsymmetric system response functions, similar' to those encountered in soft x-ray appearance potential spectroscopy and in x-ray continuum, isochromat measurements, are used in investigations of truncation errors. Abrupt cut-offs of the model S and A functions before deconvolution result in the build-up of large fluctuations in W . These truncation errors become increasingly localized with continued iterations and make only minor contributions to the errors in Wn in the vicinity of the real peak if the truncations are made sufficiently far from the peak location. Alternatively, the truncation errors can be avoided by analytical continuation.

The majority of sulfide mineral patterns in the International Centre for Diffraction Data Mineral Powder Diffraction File have historically been of low quality (e.g., FN < 10 and qualitative intensities). A five-year study has resulted in upgrading approximately 20% of the poorer quality patterns and will triple the number of “star quality” patterns. This paper describes the experimental methods used to obtain these upgraded patterns. The essential role of diffraction pattern calculations and diffractogram simulations is stressed.

Thin film technology is rapidly evolving today, and the characterization of the thin film and its surface have become very important issue not only from scientific but also technological viewpoints. Although x-ray diffraction measurements have been used as suitable evaluation methods in crystallography studies, its application to the structural evaluation of the thin films, especially organic one having the low electron densities, is not easy due to the small amounts of scattering volume and the high obstructive scattering noise from the substrate. However, the x-ray diffraction measurements under grazing incidence will aid not only in overcoming the such problems but also in analyzing in-plane structure of the thin films. Therefore, so-called grazing incidence x-ray diffraction (GIXD) has been recognized as one of the most powerful tools for the surface and thin film studies.

The fundamental-parameter technique is an important tool for quantitative x-ray chemical analysis and is routinely applied for the quantification of bulk specimens and single layer films. A method extending it to multiple film layers has recently been introduced by Mantler and results from such applications have been reported by Huang and Parrish. In addition, fundamental-parameter methods can be employed to predict intensity ratios of fluorescent lines as well as the spectral distribution of radiation scattered by the specimen (shape of the background in the vicinity of emission, lines). This is useful for accurate quantitative analysis in the case of a poor peak-to-background ratio, where the precise determination of net intensities is difficult.