X-ray fluorescence excited by a monochromatic collimated Mo-Kα beam at grazing incidence is measured as a function of the angle of incidence. Monochromatic excitation guarantees a well-defined penetration depth and enables a simple analytical description of the fluorescence intensity. This method is applied to a system of thin Cu and Ti metallization layers on a Si wafer and to As dopant concentration profiles in Si wafers.Thereby, the effect of annealing can be analyzed non-destructively.

Primary beam transmission filters in energy dispersive X-ray fluorescence (EDXRF) analysis are used to shape the spectral output of the X-ray tube. The effective use of these filters allows the optimization of excitation conditions for each different analysis. Filters are used in two basic ways in EDXRF; either as edge filters or as white filters. The proper choice of filter and excitation conditions optimizes the analysis of a particular element or spectral region by shaping the primary radiation to reduce background and to maximize excitation.

Most commercially available, automated powder diffractometers include software packages for the determination of d-values from experimentally recorded digitized patterns. While many of these patterns offer great flexibility to the user, indications from a recent Round-Robin Study [1] are that many users are confused as to the correct use of such parameters as choice of step size and counting time, the degree of data smoothing, peak-hunting parameters, setting of background level, and the consequences of background subtraction and α2 stripping. This paper will reviews these various factors and give some guidelines as to the establishment of optimum conditions.

The intermetallic compound Au4V is known to be ferromagnetic at temperatures below 43°K. Its ferromagnetism, which has been attributed to long range order, can he destroyed by cold deformation. The present study was undertaken to determine how the Bragg and Williams long-range-order parameter of the fully-ordered alloy varied as a function of deformation by cold rolling. Because of complexities in the diffraction spectrum it was not possible to determine 5 by a simple ratio of integrated intensities as is frequently done in other ordered systems, A treatment was developed to handle these difficulties using a modification of a method developed by Giamei and Freise for determining volume fractions of mixed phases. These results are correlated with magnetic measurements made by Chin and coworkers at Bell Laboratories.

A new fundamental-parameter program has been developed which corrects for light element absorption based on the mean atomic number of the sample. The mean atomic number, in turn, is determined from the Compton/Rayleigh scatter intensity ratio. The program is quite flexible with regard to the number and the type of standards which may be used. The accuracy and precision of the method has been evaluated with several geological and biological standards. The results are in good agreement with those obtained by some other methods (CEMAS, XRF-11).

A two-crystal spectrometer employing a Cole polarizer made from a germanium crystal as one of the crystals is described. Experimental tests show that placing the polarizer crystal in the second position markedly improves the degree of plane polarisation, in full agreement with the predictions of the dynamical theory of X-ray diffraction. Tests indicate that the twice-diffracted beam h better than 95% plane polarized. The angular resolving power of the instrument is comparable to that of conventional two-crystal spectrometers. The almost wholly planepolarized monochromatic X-radiation, moreover, permits certain tests to be carried out far more effectively than is possible with partly polarized X-ray beams.

A commercial micro-densitometer is run by an IBM 1800 computer under time sharing. It is used for measuring the transmission of mass spectrometer plates and x-ray powder diffraction films. The x-ray data are processed on the 1800 computer in three steps: First a linear background approximation is performed by least-squares methods, then the data corrected for background are searched for peaks and the position of the peaks is determined. After an optional manual peak selection facilitated by CRT display of the data and results, d-spacings are calculated and printed out together with approximate intensities. The programs are also used for processing data obtained By automated x-ray diffractometers.

A method for using synchrotron-radiation parallel-beam X-ray diffractometry for precision measurement of scattering angles and lattice parameters is described. The important advantages of the method are the high P/B made possible by wavelength selection and high source intensity, the symmetrical profiles and the absence of most systematic errors making it unnecessary to use standards. Profile fitting with a pseudo-Voigt function is used to determine 2θ to 0.0001º. The zero-angle correction and lattice parameter were determined from least-squares refinement and the average accuracy of observed-calculated 2θs was 0.0020°. Average values of ∆d/d = ∆a/a directly calculated from the individual hkl measurements ranged from 2x 10-5 to 5.7 x 10-5. The precision estimated from the standard deviation of the mean is in the 10-6 range and 1 ppm precision was obtained for Si. The determination of the exact wavelength selected remains to be solved, but ratios of lattice spacings to standards such as NBS SRM 640a can be determined.

An X-ray Micro-Fluorescence (XRMF) spectrometer, with an analysis area of about 100 by 150 microns, has been used to collect 2-dimensional X-ray intensity maps over large-area (5 to 50 mm in X and Y) samples. These intensity maps were collected by scanning the sample on an XY stage, and converting X-ray Energy-Dispersive spectra to peak intensities for the elements of interest. The maps, when displayed using false-color or pseudogray scales, show the distribution of individual chemical elements over the analysis area. These maps can be collected at speeds from about 1 minute per frame (analysing 25 elements simultaneously). Greater precision of chemical intensities, or larger area maps, may require several hours, particularly if extensive data processing is performed at each point. XRMF has advantages over more conventional SEM-EDS X-ray mapping, including sample preparation and presentation, as well as improved signal-to-noise ratios.

A technique is described which assists in analyzing the large amount of data which is collected in each map. Principal Component Analysis (PCA) is performed on all of the elemental maps simultaneously. This technique compresses the many elemental intensity maps into a few principal components, resulting in many fewer maps to evaluate. The intensity maps of these principal components display the most pertinent information. They can also be plotted as scatter plots which can help with the partitioning of the data into individual phases. This procedure can potentially be automated as a method for phase analysis. The selected pixels from the scatter plots can be averaged and converted into phase compositions, and the phase information re-displayed on the original elemental or principal component maps.

This technique has been applied to a thin section of rock, and to a synthetic multiphase alloy sample.

The fluorescent excitation of long-wavelength X-ray spectra is reviewed with respect to X-ray tube target element, inherent filtration, and optimum kilovoltage. A demountable X-ray tube vacuum spectrograph designed for the determination of the light elements is described. Operation of this instrument with both secondary and combined primary—secondary excitation is evaluated. Examples from the literature are cited to show the feasibility of direct electron excitation of longwavelength spectra.

A project was undertaken to compare the Williamson-Hall and Fourier teclrniques for analyzing particle-size and micro-strain induced x-ray line profile broadening. The four alumina powders analyzed in the study were the candidates from which SRM 676, a quantitative analysis Standard Reference Material, was chosen. SRM 660 (LaB6) was used to determine the instrument profile function, IPF. However, difficulty was encountered in fitting an appropriate mathematical model to the IPF data; this prevented the application of Fourier analysis methods and restricted the number of profiles that could be analyzed with the Williamson-Hall method. The size/stain data compared favorably with other microstructural data collected on these specimens.

Various sample preparation methods for Energy Dispersive X-ray Fluorescence (EDXRF) analysis of Portland cement were compared in order to evaluate improvement in analytical accuracy and precision. Sample preparation requirements for EDXRF are slightly different than for Wavelength Dispersive X-ray Fluorescence (WDXRF), and the methods commonly used in WDXRF are not optimized for EDXRF. Primarily, the work focuses on techniques for producing a fused sample with the lowest practical concentration of lithium borate flux. Determination of minimum detection limits were made from samples with varying proportions of flux in order to evaluate analytical optimization. Ease and reproducibility of preparation of the sample was also considered.

The strain distribution associated with incipient microplasticity and its response to subsequent annealing were studied in smooth and notched silicon crystals. The characterization of plastic and elastic residual strains was carried out by X-ray topography based on PendellBsung Fringe (PF) patterns and was supplemented by X-ray doublecrystal diffractometry and specimen scanning with automatic Bragg angle control (ABAC). It was shown that the sites at or near the surface were preferred sites where, upon mechanical deformation, dislocation sources became activated. Microplastic zones thus formed constrained long-range, residual, elastic strains.

An algorithm is proposed as a model that describes the intensity concentration relation over a wide concentration range in binary and more complex systems involving absorption and enhancement. All the influence coefficients can be determined from fundamental parameter equations. Terms containing product of two weight fractions are always negligible in pure absorption cases, are often negligible in absorption/weak enhancement cases and are necessary but small in strong absorption/strong enhancement situations.

Once the magnitude of the coefficients is known, the range of application of the one- or two-coefficient models can be established with certitude.

We present the results of a preliminary study of the use of polychromatic synchrotron radiation in energy-dispersive mode for the rapid characterization of thin film and multilayer materials. This technique takes advantage of the high intensity and excellent collimation properties of white beam synchrotron radiation. The glancing angle diffraction geometry allows structural depth probing as well as enhanced signal-to-noise by suppressing substrate contributions. The technique was successfully applied to metallic films a few hundred Angstroms thick, and to W-C multilayers.

X-ray fluorescence spectroscopy has been in use since the early days of the twentieth century, when Moseley confirmed the order of the chemical periodic table. However, fluorescence spectroscopy until recently has depended on diffraction methods to obtain sufficient resolution. Intrinsic resolution of ionization chambers, scintillation detectors, and proportional counters is inadequate for discrimination o f lines due to adjacent elements of low atomic number. The advent o f solid-state detectors, especially those using lithium-compensated silicon and low-noise electronics, has recently brought intrinsic energy resolution to the point where lines from adjacent elements as light as carbon and nitrogen can be resolved in theory; and detection of K radiation from elements as light as sodium is practical. Thus the solution to the long-standing problem of an adequate detector is at hand, and energy-dispersive spectrometers are now feasible.

Pentaerythritol (C-(CH2OH)4) is a solid-state phase-change material which is a potential candidate for temporary storage of solar energy. This material is known to undergo an atomic structural rearrangement in the solid state above approximately 187°C, at which point a large amount of thermal energy is absorbed. Reversion of the structure to the low-temperature form releases this stored energy–thus pentaerythritol (P.E.) can be regarded as a temporary storage medium for heat.

Sampling is a necessary part of the chemical analysis of particulate matter where the objective is to characterize bulk properties since it is usually undesirable or impossible to test an entire lot. The sample must be a miniature replica of the bulk material at least in respect to those features being tested. In other words, the sample must be representative to permit extrapolation from the sample to the bulk.

There is error associated with sampling particulate material, but this sampling error is only one component of the total error associated with an analytical result. Sample preparation and determination of the property being tested are two other major sources of error, These three errors combine as the squares of their standard deviations, i.e., their variances, to produce the total analytical error. Very often, sampling error is the largest of the three and, therefore, contributes a disproportionately large share to the total error.

As part of a study on the fundamental properties of BeO, the surface area, particle size, and crystallite size of BeO powders prepared from different source materials were measured. The results obtained by means of small-angle X-ray scattering and X-ray line-broadening have been compared with electron micrographs and surface area values by air permeability, nitrogen adsorption, and water-vapor adsorption.

Small-angle scattering data were analyzed to yield particle size distribution curves as well as surface areas for various calcined BeO samples. Line-broadening measurements were made to determine mean crystallite dimensions of these same materials. By using both photographic film and automatic recording techniques, crystallite sizes from about 50 to over 5000 A were estimated. The rate of growth of BeO crystals from beryllium hydroxide, beryllium sulfate, and beryllium oxalate source materials has been followed by these complementary techniques.

For pole figure measurement the flat sample has to be tilted which leads to peak broadening and peak overlap in peak-reach diffraction spectra. Using a linear position sensitive detector /PSD/, complete diffraction spectra can be obtained in each sample orientation. Peak separation can then be done by Gaussian fitting. When measuring with a PSD, each diffraction peak corresponds to a particular diffraction vector. This has to be taken into consideration by a coordinate transformation. The PSD-method is the only practical method of texture measurement for materials with complex diffraction spectra.