For time-resolved diffraction studies under high temperature and/or high pressure, we designed a new diffractometer incorporating a curved position sensitive detector and tested the rapid intensity measurement and the resolution of the angular dispersive diffraction. The diffraction profiles were compared with those from energy dispersive diffraction. Rapid intensity collection has been carried out with a CAMAC module. A curved position sensitive detector with a 120° working angular region was installed on the off-centered four circle diffractometer. Only a few seconds were needed to obtain a whole powder diffraction because of the extremely high counting efficiency due to the streamer mode.

Time-resolved observations of the dehydration reactions of Mg(OH)2 and Ca(OH)2, have been undertaken by angular dispersive and energy dispersive x-ray powder diffraction at high temperature. The in situ observations of the dehydration process provide kinetic information, such as the reaction rate, the apparent activation energy and the dehydration mechanism.

A single function for the elimination of errors in precision lattice parameter determination has not been developed for the Bragg-Brentano x-ray diffractometer method, because of the different angular dependencies of the systematic errors. A review of the error functions shows that all but one can be calculated from the instrumental settings and known properties of a sample under investigation. The residual sample displacement error can be then be eliminated by using extrapolation plots or computer methods to correct the data to cosθcotθ plots. The slopes of cosθcotθ plots can also be used to align high temperature furnaces and low temperature cryostats mounted on x-ray diffractometers.

The magnetic crystal disrortion of weakly ferromagnetic α-Fe2O3 was investigated by x-ray diffraction techniques. Here crystal distortion is taken as the temperature dependent changes of lattice constants and thermal expansion coefficients. Moreover, the oxygen position parameter and the carbon-oxygen distance of MnCO3 were determined.

The lattice constants and thermal expansion coefficients of α-Fe2O3 were measured from room temperature down to 243°K. The crystal distortion, as measured by the changes in lattice constants, thermal expansion coefficients and axial ratio, was found to be highly anisotropic. The co hexagonal lattice constant was influenced very slightly by magnetic distortion; it changed only by 0.01 percent between room temperature and the Morin temperature of 254°K. On the other hand, the ao lattice constant changes by 0.11 percent between room temperature and the Morin temperature. The thermal expansion coefficients of the lattice constants showed a similar contrast. The co coefficient was found to be independent of temperature from room temperature down to the Morin temperature. However, in the same temperature range, the ao coefficient showed an anomalous increase with decreasing temperature. In addition, the ao coefficient showed an infinite discontinuity at the Morin temperature.

The change in the axial ratio with temperature suggests that the net weak ferromagnetic moment of α-Fe2O3 reaches a maximum at 275°K.

The oxygen position parameter, x, in MnCO3 as determined from two reflections has a value of 0.2702 ± 0.001. The carbon-oxygen distance as calculated from the lattice constants and the oxygen position parameter is 1.29 ±0.002 Å. This value is another confirmation of the Pauling theory of the resonating carbonate structure.

X-ray powder pattern line intensities were measured for the (Cr, Re)σ and (Re, Fe)σ phases by a step-scanning diffractometer, using CrKα radiation, scintillation counter, and a pulse height analyzer. The measured intensity ratios for all available pairs of adjacent lines were compared by means of a computer with the corresponding calculated intensity ratios based on approximately 1800 different ordering schemes for each alloy. The results showed ordering in both alloys, and indicated that the ordering was based on atomic size. These results are different from those obtained previously by Kasper and Waterstrat (no ordering), and by Ageyev et al. [In (Cr, Re)σ the Cr atoms are preferentially in large coordination number positions.]

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.

We have recently described an automated powder diffractometer, the APD-3500, in which a small (4K x 18 bit) minicomputer is utilized for hardware control and data processing. Among the software programs developed for this system is a “Peak Search“ routine which is designed to record a diffraction pattern with optimum, use of scanning time and to give output directly in J.C.P.D.S. Powder Data File Format. Optimum use of scanning time is achieved by a double-pass System in which a first (rapid) pass is made to establish significant data.

A second routine is a “Line Profile” routine which gives the choice of rapid slewing or slow Step scanning of the goniometer between selected angular ranges. The routine thus allows the controlled stepping of the goniometer between selected angular ranges giving incremental and integral, background corrected counts. An automatic internal and/or external calibration capability makes this particular mode ideal for quantitative analysis.

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,

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.

There is considerable interest in the microelectronics industry to obtain high-resolution images, as well as precise measures of defect densities in “ device quality” thin films and substrates. In the field of x-ray diffraction, research groups worldwide are intensely pursuing the relevant applications of computerized x-ray rocking curve analysis and topography. Production-type, on-site rocking curve instrumentation has already been introduced into the market, and potential uses of x-ray topography are also under consideration.

In the present study, the merits and limitations of these two techniques are critically evaluated. Possible pitfalls of automated data collection are pointed out and conditions under which meaningful measurements may be made are explored. It is shown that reliable results may nearly always be obtained with reasonable care when each method is applied subject to its own mode of operation. However, extreme caution is needed when digitized data initially collected for topography is subsequently used for rocking curve analysis; otherwise, the correspondence between the interpretation and actual defect configuration may be vitiated. Thus, additional tests will be necessary to ensure the validity of the results.

Quite recently there has been commercially developed a series of high-alloy steels, on new compositional bases, which possess 3 very desirable combination of unusually high strength, good ductility, and toughness even at comparatively low temperatures. At the same time, research with mechanical working procedures, combined with optimum heat-treat considerations, have produced with several older, more conventional steels, strength levels of high orders of magnitude. Each of the considered materials is capable of yield strengths approaching or exceeding 300,000 psi, corresponding to elastic strains of about 1%.

This paper is concerned with the development and evaluation of workable X-ray stress analysis procedures to be employed to measure, with a good degree of accuracy, high elastic strains. The materials selected include maraging steels, ausformed steels, and cold-drawn A.I.S.I. 4340 steels.

Of the various possible X-ray techniques which were considered, very satisfactory results were obtained by the use of the two-exposure method. A special fixture was designed and constructed to allow uniaxial straining of test specimens while in the X-ray unit. Imposed strains were measured directly by strain gauges mounted on tbe specimen. Simultaneously, strains were measured by the use of chromium radiation filtered with vanadium foil. The peak resolution obtained was very satisfactory with a peak to background ratio of approximately 4:1 for the {211–121} martensite doublet used to measure the shift in peak location between the normal and oblique exposures. Because of the widths of the peaks involved, it is impossible to precisely specify the angular position of a given peak by inspection of the usual recorded trace. A counting technique, combined with a least-squares curve-fitting procedure involving five points, was very satisfactory for precisely locating positions of maximum intensity, Superior results were obtained when a multiplicative correction factor proposed by Koistinen and Marburger was applied.

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.

Minor amounts of rare-earth elements (0.01 to 1.0%) in high-purity rare-earth oxides may be determined by a fluorescent X-ray procedure. The analysis of high-purity yttrium, cerium, praseodymium, neodymium, and samarium is described. Basic to the method is accurate determination of spectral line intensity above background. Sample and standard preparation, choice of analytical lines, and utilization of a helium path to increase X-ray intensities are discussed. Precision and accuracy were evaluated by analyzing samples of known composition. The average of five separate determinations showed an average error of about 10 per cent.

An x-ray diffraction study of the reversible deformation inodes associated with the shape memory effect has been carried out on a series of uranium-niobium alloys near the monotectoid composition (6.2 wt. % Nb). Diffraction patterns were measured as a function of strain, in situ, while the specimens were under stress as part of an attempt to explain the “easy-flow”, low-strain plateau in the stress-strain curve. The alloys, consisting of highly twinned, metastable α” (monoclinic) and γ° (tetragonal) phases derived from the high-temperature BCC γ phase, produced broad, overlapping diffraction lines difficult to analyze by conventional techniques. One solution to this problem was to use a segmented step-scan technique so as to apportion the scan time to concentrate on the most difficult regions. This paper discusses data obtained from an α” alloy and a dual-phase α” + γ° alloy.

The high-temperature continuous X-ray diffraction technique has been used at the University of Illinois for several years in our investigation of structural transformations and the development of phase minerals as natural materials are heated. Of particular interest are the effects which chemical impurities have on predicted structural transformations at elevated temperatures.

The formation of mullite and beta-cristobalite as they develop from the clay mineral kaolinite is examined by continuous X-ray diffraction up to 1450°C, and the influence of added impurities either to enhance or to retard nucleation of these phase minerals is shown. The 2θ range containing diagnostic peaks of both the initial material and of the transition and phase minerals which develop on heating was continually traversed, thus providing a constant record for comparing structural changes vs. temperature.

The furnace used is described in detail, and the effects of added impurities on kaolinite transformations are evaluated to show their importance in controlling the thermal history of a natural material under nonequilibrium conditions.

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.

The excitation efficiencies for K- and L- x-ray fluorescence by a Mo transmission tube operated at 30 kV have been measured. K x-ray excitation efficiencies for 14 elements ranging from A1 to Y and L x-ray excitation efficiencies for 12 elements ranging from Br to U are presented. The K x-ray excitation efficiencies are compared to those predicted from theoretical photoionization cross sections and empirical fluorescence yields, and the L x-ray excitation efficiencies are used in conjunction with theoretical photoionization cross sections to derive average L-shell fluorescence yields.

The instrumentation for measuring x-ray yields from laser produced plasma is described. This new type of calorimeter is composed of a silicon detector, a charge-sensitive preamplifier and an analog-to-digital readout scheme for multiplexing up to ten detector outputs.

X-rays interacting with the detector produce hole-electron pairs in proportion to the total energy lost in the detector (∼1012 eV). In this application the detector can be characterized as a solid-state ionization chamber. The detector signal is coupled to a charge-sensitive preamplifier which generates a voltage pulse proportional to the x-ray energy absorbed. In this way the x-ray energy is measured by “direct conversion” rather than measuring the temperature rise due to an energy flux.

During recent years energy dispersive x-ray fluorescence (EDXRF) has been used to measure the elemental content of atmospheric aerosols. The code described here is used to reduce EDXRF data and determine the elemental composition of samples collected on membrane filters. The program has been specifically written for EDXRF analysis of size-fractionated aerosols collected by a dichotomous sampler.

The x-ray fluorescence spectrometer used in our laboratory employs a pulsed-mode x-ray tube and a lithium-drifted silicon detector. Pulse-height spectra are produced for elements ranging in atomic number from Z = 13 to Z = 82 (corresponding to an energy range from 1.4 to 32.1 keV). Approximately uniform x-ray production is attained by producing independent spectra from three secondary targets (Ti, Mo, Sm).

This is a review of Total reflection X-Ray Fluorescence (TXRF) applications for semiconductors. This review is limited to surface analysis of contamination for semiconductors and does not include chemical analysis in semiconductor processing. TXRF for surface analysis is a relatively new technology. One of the first publications occurred in 1986 using synchrotron radiation. Publications using commercially available TXRF instruments for semiconductor applications began in 1988. Today there are on the order of 100 TXRF instruments worldwide in the semiconductor industry. Since 1988 there have been about 100 publications in this field, but this number does not include numerous abstracts and publications in Japan where the majority of the commercial instruments are found today. The commercial instruments were developed for the primary application of characterizing the cleaning of planar silicon wafers, however, numerous unforeseen applications were developed by users and many of those applications are reported here. In essence TXRF has much broader application today in the semiconductor industry than supporting the cleaning of silicon wafers.

Two years ago a paper on a new method of X-ray fluorescence analysis was presented. This method uses a variable take-off geometry and permits a quantitative analysis without calibration curves or the knowledge of the primary X-ray spectrum. As references either chemically analysed samples or pure elements are used. In case that only primary excitation exists, under the aspect, mentioned above, the method is to be regarded as “absolute”. For secondary excitation a simple parabolic approximation has been introduced, which requires a calibration. This paper gives an outline on the progress obtained during the last two years.