Recent developments in position sensitive detectors (PSD's), solid state power and computer technologies make it possible to design accurate instruments for in-situ stress measurement. Such instruments require compromises in the interests of portability, size and speed stiich may limit accuracy and/or versatility. Furthermore, extraction of a stress tensor from X-ray data is not always straightforward and considerable research is required before an instrument for X-ray stress measurement can be treated as a “black box” to be given to an uneducated operator.

The development of a new instrument for in-situ stress measurement is described in this paper. It was conceived as a field instrument with two position-sensitive proportional counters (PSPC's) for use in the single exposure mode (SET), and incorporates precise angular qontrol of the incident X-ray beam and data analysis to eliminate irregular Bragg peaks owing to coarse grain structure, An experimental instrument was built tc test the concept (1).

X-ray micro analysis had suffered from the limited intensity of conventional X-ray sources like X-ray tubes etc. However, with the optical technique described in this paper, the so called “X-ray Capillary Optics” (XCO), it is possible to make X-Ray Fluorescence (XRF) analysis in micro-scale, down to a few μm2 still with conventional sources.

Recently, semiconductors have been integrated and densified to much higher levels. Under this circumstance, control of surface impurity on the Si substrate has become more important. We have attempted to increase analytical sensitivity of the transition metals, which have the greatest influence on productivity.

For the last few years, x-ray fluorescence analysis, using total reflection as a non-destructive and speedy method, has been applied for surface impurity analysis of Si wafers. However, this method is insufficiently sensitive (to the level required for surface impurity analysis) and the lower detection limit is still 1011 to 1012 atoms/cm2 order because the continuous x-ray excitation causes lots of scattering which makes the background higher.

A theoretical approach of some factors influencing the intensity diffracted by a polycrystalline material at a definite Bragg angle has been confirmed by experimental data obtained with a high-angle Norelco diffractometer. The factors mainly considered are the focusing arrangement of the goniometer which delineates the geometric shape of the volume fraction of the sample being irradiated and the absorption of the latter.

Tests have been performed (a) with quartz mixed in samples covering a large range of absorption coefficients, (b) with two different K radiations using copper and molybdenum targets, (c) with three different angles of beam divergence of 1, ½, and ¼°, respectively, and (d) with the sample packed and leveled in a copper grid with openings of about 350 μ. As this test with copper grids was to demonstrate that each opening was acting like a volume of sample irradiated by a beam of extremely small divergence (0.1°), it also shows that more accuracy in the measurement of the exact Bragg angle can be reached in these conditions as compared to that obtained with conventional sample holders.

A general equation, suitable for qualitative and quantitative analysis when these factors have to be taken into consideration, is proposed.

Calibrated powder patterns of a number of high symmetry crystalline materials were recorded in three different Guinier-type focusing cameras. The films were then measured by three different techniques, one visual and two instrumental. Cell parameters were calculated by three different data reduction procedures. The aim of the work was to establish the level of reproducibility for cell parameters obtained in routine work with these instruments.

XRF can be a powerful tool for quantitative elemental analysis-it can also be a big headache. The problem is, of course, that to perform a proper quantitative analysis one needs to first develop a good matrix correction model to convert the measured line intensities to concentrations. For empirical models, aside from the inherent difficulties in optimizing a set of interelement correction coefficients, the commercially available computer controlled spectrometers have in the past either provided rather poor regression analysis programs with their software or none at all. The reason for this has been the rather limited core size of the online computer and the lack of fast efficient mass storage facilities such as floppy disks.

X-ray diffraction studies on radioactive materials are reviewed. Considerable emphasis is placed on the safe handling and loading of not-too-exotic samples. Special considerations such as the problems of film blackening by the gamma rays and changes induced by the self-irradiation of the sample are covered. Some modifications of common diffraction techniques are presented. Finally, diffraction studies on radioactive samples under extreme conditions are discussed, with primary emphasis on high-pressure studies involving diamond-anvil cells.

Consideration of variations in atomic potentials permits an estimation of the mass absorption coefficients of many elements for the characteristic emission lines of carbon, nitrogen and oxygen. The accuracy of (μ/p) values presented is better than 5% in most cases. These values are tested in the microanalysis of defect titanium carbides. Limitations of the theoretical correction procedures lead to the definition, of a set of analysis conditions which permit carbon analysis to within 1.0% absolute.

Thermal analysts have exploited the sensitivity of carbonate mineral decomposition to furnace atmosphere as a diagnostic tool for identifying and quantifying these minerals in mixtures and solid solutions (1-3). However, thermal analysis techniques alone cannot reveal information about the reaction products after each thermal event. In-situ high temperature x-ray diffraction is one technique that can identify these products. Using this technique, Kissinger et al. (4) identified the reaction products of the thermal decomposition of reagent grade FeCO3 (siderite) and MgCO3 (magnesite). However, the thermal behavior of analytical reagent grade carbonates differs from natural minerals (1). Milodowski and Morgan (5) used in-situ XRD to investigate the thermal behavior of the dolomite-ankerite series.

It is well known that x-ray diffraction techniques provide one of the most direct means of analyzing superlattice periodicity, layer thickness, strain, and defect structure. This suitability of x-rays is a consequence of the fact that most superlattice periods are in the range of 10 to 50 times the typical wavelength (Cuκα=1.54 Å) and are hence measurable by x-ray diffraction, and also that x-rays are non-destructive within the energy and dosage ranges needed for these studies. Applications of x-ray techniques to supperlattices have been discussed in many publications in the open literature.

A prototype Environmental Monitoring Device (EMD) has been developed as a simple means for inexpensive, routine determination of site severities. The EMD is a cartridge that can be connected to an inexpensive pumping unit to collect an atmospheric sample. The field procedures are extremely simple and have been done routinely by individuals with no chemical training. Four filters within the cartridge selectively react with and permanently trap pollutants from the air drawn through the cartridge. The first filter collects particulates. The second is o-tolidine impregnated Whatman #41 filter paper to collect gaseous chlorine species. Silver nitrate impregnated paper collects reactive sulfur gases, and the fourth filter paper is impregnated with sodium hydroxide to react with and collect sulfur dioxide. After atmospheric sampling, the cartridges are returned via mail to a central analytical lab. Procedures have been developed for easy and rapid determination of the quantities of pollutants on the filters by energy dispersive X-ray fluorescence. Laboratory and field measurements from a number of locations within the IBM Corporation have been made and will be reported. The EMD approach is providing a large data base on indoor atmospheric pollutants that could affect electronic equipment. The approach could easily be extended to numerous other applications.

Basic lead azides are obtained by the slow thermal decomposition of PbN6 at temperatures up to 200°C in oxygen, argon, and air containing varying amounts of moisture. The decomposition diagrams show several stages due to the formation of different phases, two of which have been separated. One phase can be identified as a tetragonal deformed cubic lattice. Further slow decompositions of the basic lead azide at 250°C lead to tetragonal lead oxide. The structure of the other isolated phase Is of lower symmetry and has not yet been classified. The results of this investigation are also compared with the work of previous investigators.

The analysis of alpha-excited X-rays has been studied as a possible addition to the alpha-scattering technique used on the Surveyor spacecraft for the first in situ chemical analyses of the lunar surface.

Targets of pure elements, simple compounds, and silicate rocks have been exposed to alpha particles and other radiation from a curium-214 source and the resulting X-ray spectra measured by means of a cooled lithium-drifted silicon detector and pulse-height analysis.

Alpha-particle bombardment is a simple and efficient means of X-ray excitation for light elements. Useful spectra of silicate rocks may be obtained in a few minutes with a source activity of 50 millicuries, a detector area of 0.1 cm2 and a sample distance of 3 cm. An advantage over electron excitation is the higher characteristic response relative to the bremsstrahlung continuum. Peak-to- background ratios of greater than 100 to 1 have been obtained for elemental targets. Relative efficiencies of X-ray excitation by alpha particles and by X-rays from the curium source have been determined.

Resolution of the detector system used is approximately 150 eV for the lighter elements. This is sufficient to resolve the Kα X-rays of the geochemically important elements, Na, Mg, Al, and Si in silicate rocks. Although these and lighter elements are analyzed as well or better by the alpha-scattering and alpha-proton technique, the X-ray mode enables results to be obtained more quickly.

The study shows that the addition of an X-ray mode to the alpha-scattering analysis technique would result in a significant improvement in analytical capability for the heavier elements. In particular, important indicators of geochemical differentiation such as K and Ca (which are only marginally separated in an alpha-scattering and alpha-proton analysis) may be determined quantitatively by measuring the alpha-excited X-rays. An X-ray detector is under consideration as an addition to an alpha-scattering instrument now under development for possible use on a Mars-lander mission.

One of the most important applications o£ XRF in the oil industry has been in the analysis of oil additives which range from Mg to Ba. In such a low atomic number, hydrocarbon matrix, small variations in the additives cause pronounced changes in the average atomic number of the matrix and hence give rise to strong interelement effects. In recent years a number of mathematical methods have been developed to correct the measured X-ray intensity of the analyte litie for these considerable effects. This paper describes a method for the determination of Zn,Ba,Ca,CI,S,P and Mg in oil additives using a concentration based correction model in which influence coefficients (alphas) are applied.

Brieketted rock powder discs provide a convenient type of specimen for use in x-ray fluorescent analysis for both major and trace elements. The method is limited because variation of matrix makes calibration difficult over more than a limited range of specimen compositions.

Standard grinding and preparation procedures together with a ratio technique of measurement eliminate variation except that arising from chemical, mineralogical and particle size differences. Several series of standard rock samples have been prepared and the variation of measured intensity per unit concentration have been investigated for the analytical Lines of silicon, aluminium, iron, selenium and cadmium. Computer methods of multivatiate regression analysis have been used to calculate empirical correction factors based on this data and the mineralogical and chemical composition of the specimens. These correction factors have been used to correct the measured intensities of other specimens measured in separate experiments.

Energy dispersive X-ray fluorescence (EDXRF) spectrometry has been applied to the high speed analysis of uranium ore for the purpose of grading and sorting truckloads of ore at the mine. The system is able to analyze uranium ore in less than 60 seconds with uranium levels ranging from < 0.005% to > 5% U3O8. Precision at the 2σ level for 200 ppm ore is better than 10% relative. Good agreement is obtained with wet chemical results in a large variety of rock matrices.

An IBM 1800 time-sharing system is used in our X-ray laboratory to control a four-circle diffractometer for structure research, several powder diffractometers, a pole-figure goniometer and a microdensitometer along with other instruments outside the diffraction area. A survey of the computer system is given and the hardware necessary to automate the diffractometers is discussed. The computer supervision ranges from simple data-logging with a minimum of control to complete control of all actions depending on the diffractometer and the requirements of the experiment. Also described is the use of the computer to process the data and to perform background jobs.

The wafer analyzer has been used to fulfil many applications needs in the semiconductor industry. The prominent features of the XRF method for the semiconductor industry are:analysis of many types of films, e.g., oxides, silicides and metallic alloys, and simultaneous analysis of film thickness and compositions.

In the past, the analysis results of BPSG (Boron-doped Phospho-Silicate Glass) films, with thicknesses greater than 4000 Å, were reported. With the recent increased demand for larger scale and higher quality semiconductor devices (larger than 64 Mbit), more accurate analysis with high precision has been required.

Capillary collimators have found a number of uses in fluorescence, diffraction and other x-ray fields. Most of these applications are realized with single, straight glass capillaries. Focussing of synchrotron x-radiation beams has been shown with tapered capillaries. In addition, numerous straight and bent capillaries, bundled into lens-like optics, offer experimenters many other possibilities for better use of the x-radiation from tubes, synchrotron radiation, and plasma sources or the x-ray intensity collected from samples.

This review will attempt to show how XPS now makes an important contribution to Materials Science and to highlight the developments which have brought it to this position. XPS is now a mature technique for surface analysis but it has in addition a major role as a specialised tool, being essential to studies in which derivitization methods are used to tag surface groups.

The requirements of users in this field have led to the development of X-ray sources which were not envisaged in the early development of the spectroscopy. The usual sources of aluminium Kα and magnesium Kα have limitations for those elements beyond magnesium in the periodic table which would have the Is lino as the principal peak - aluminium, silicon, oulphur and phosphorus for example. Higher energy sources such as silicon Kα or zirconium and silver Lα have made it possible to utilise the Is lines up to chlorine and have the additional advantage that a strong and well resolved series of Auger lines also becomes available. The higher energy radiations are thus particularly suited to the determination of relaxation energies in materials by use of relative shifts between the photo- and Auger lines of the spectrum. Such has been the utility of such relaxation energies that use is often made of Auger lines derived from the Bremmstrahlung component of the normal x-ray sources to make a similar measurement. This measurement is used in the study of insulating ceramics in which electrostatic charging makes measurement of binding energies uncertain.

Modern materials technology is particularly concerned with the manufacture of composites; particulate, fibre and laminate composites are all well known and the key to their success often lies within the interface between the phases. Transfer of load across the interface places particular requirements on adhesion at the phase boundary and an understanding of the locus of failure during destructive testing is crucial to the development of satisfactory bonding processes. In coated and laminated products there is no problem in the use of XPS, with its excellent chemical sensitivity but there is a problem of increasing magnitude in fibre and particulate composites as the substructures become finer. This stems, of course, from the difficulty of providing a focused source of X-rays of sufficient magnitude. Imaging XPS is slowly becoming a reality with several systems having a capability of 10μm now available, and one of the markets for such instruments is that of composite materials.

There are important areas of Materials Science in which XPS has been displaced by other techniques such as SIMS. One such area is that of polymer surface analysis. The selectivity of XPS for substituent groups in the surface region is not good. Derivitization methods have made an impact, enabling acidic or basic groups to be determined, but SIMS, which has the ability to detach molecular clusters, has obvious advantages which will become increasingly exploited aa the problems of charging become solved. Until then however XPS will continue to find a role in polymer research and development.