The need for rapid and accurate analysis of lubricating oil additives is firmly established by the petroleum industry. The application of energy dispersive X-ray fluorescence spectrometry techniques to this analysis is a valuable aid in achieving reliable and fast quality control of these product types.

Due to the large concentration variations possible for the elements of interest within these materials (principally Zn, Ca, P, S at 0-20%), interelement effects can become significant. In order to correct for interelement effects, historical XRF methods have relied on a large number of standards for each element to be determined or matrix matching with standards closely bracketing the unknown sample concentrations.

A precise method for detenaining unit cell dimensions of semiconductor single crystals has been developed. An accuracy of ± 0.00002 Å and a precision of ± 0.00001 Å is achieved.

The method is used to determine variations in the cell parameter of GaAs as a function of surface defects, homogeneity across and along an ingot, evaluation of epitaxial layers, effects of heat treatments and structure defects induced by oxide diffusion masks on a substrate. The application of the technique to GaAsP alloys permit accurate and rapid study of sample composition and homogeneity.

Advances over the last ten years in computer automation and control, compact and portable x-ray sources, and reliable and efficient detector systems have allowed X-Ray Determination of Residual Stress (XRDRS) measurements to become a viable method of evaluating the state of stress in metals, alloys, and ceramics. However, problems associated with incorrect XRDRS equipment operation and poor experimental technique are prevelant in industry, necessitating better operator training and education. Therefore, an interactive computer workstation, called RS/hyper, was developed to lead the operator towards correct operating procedures and reliable experimental technique.

Proper machine setup, machine maintenance, radiation safety, experimental technique, theoretical understanding, and limited data evaluation are presented in RS/hyper. Graphical aids are used extensively to avoid confusion and misinterpretation of theoretical concepts and equipment instructions. RS/hyper is interactive, allowing the user to learn about topics at a comfortable level of explanation. Compared to written texts and references, RS/hyper has been shown to reduce training and problem solving time by a factor of 16.

RS/hyper will train novice users of XRDRS equipment so that the data acquired from such machines will be reliable in an industrial environment. Also, since the software educates the user, data will be more accurately represented before interpretation. The experienced user should find RS/hyper useful as a reference to XRDRS and related information.

Spectrum analysis in the ultrasoft X-ray region is complicated by the fact that this radiation is almost totally absorbed in any medium. This has necessitated spectrometer components which minimize this effect. Nondispersive and total reflection techniques, though high in speed, lack good resolution and in the case of the latter, are usually restricted to analysis of elements differing by at least three atomic numbers.

Diffracting media which have proven successful are the long-chain organic crystals and gratings at grazing incidence. The grating is superior to the organic crystal concerning resolution and dispersion and has proven to be comparable arid in some cases better for peak intensity and line-to-background ratios.

Lightly-ruled gratings have been used for many years, but little attention has been given the blazed grating until recently. Since the critical angle of total reflection for a given material is wavelength-dependent, it may be utilized to discriminate against shorter wavelengths and thus improve line-to-background ratios. The optimum conditions for sensitivity, then, would be to relate the input angle to the blaze angle and vary the input angle as a function of wavelength, thereby maximizing the line intensity or the line-to-backgrourid ratio as required.

Several gratings with varying blaze angles and surface finishes are evaluated with O Kα (23.7Å) and C Kα (44Å) radiation.

The importance of groove profile is emphasized by comparing the profile as determined by the electron microscope with the experimental evidence. The variation of diffraction efficiency with wavelength and input angle is then considered theoretically and compared with experimental results.

There are various methods for handling the problem of interferences. One may me one of the weaker lines of the trace clement, but this results in considerable loss in the limit of detectability of this element. One may try pulse height discrimination techniques, but because of the linearity limitations of present day pulse height analyzers, complete elimination of the higher energy wave length is not possible. Another possible technique is to lower the kilovoltage below the excitation potential of the interfering element. This is satisfactory, but again the limit of detectability is raised for the trace element. There are many other “devices” which may be tried, but all of these involve a loss in sensitivity in the determination of the trace element.

The “novel” approach involves the use of an analyzing crystal whose second order reflection is missing due to crystal structure considerations. Germanium or silicon, cut so that (111) planes are parallel to the surface of the crystal, would be satisfactory analyzers for this purpose. The use of one of these crystals and the application of this method to the niobium-tantalum and zirconium-hafnium systems are discussed.

In order to develop an optimum system for flash x-ray diffraction, consideration must be given to both optimum x-ray generation and optimum x-ray detection in the correct wavelength regime suitable for diffraction. Historically, most workers have concentrated their efforts in either the generation area or detection area, but not both. As early as 1942, experimental recording of Laue diffraction patterns was reported using a pulsed x-ray generator and exposure times of milliseconds. Recently, successful x-ray diffraction experiments have been reported with exposure times less than 100 nanoseconds.

The purpose of the present paper is to trace the development of generation and detection systems for flash x-ray diffraction and to summarize the present state-of-the-art for such systems. A comparative evaluation is presented for flash x-ray diffraction systems using generators which rely on increased electron beam current and those which rely on higher potential difference. Comparison is also made between detection systems incorporating film recording, scintillators fiber-optically coupled to photomultiplier tubes, and image-intensifier systems both lens and fiber-optically coupled to fluorescent screens.

A detailed description of the most rapid flash x-ray diffraction system developed to date is given. This system uses a Field Emission Fexitron single channel 300 kilovolt pulsed x-ray generator incorporating an x-ray tube with a beryllium output window. A fluorescent screen converts the x-ray diffraction image into a visible one and this visible image is focused on the first stage photocathode of an image intensifier tube either by direct fiber-optic coupling or by using a coupling lens. The image intensifier tube used is a cascaded three-stage electrostatic focus type with fiber-optic input and output faceplates and inter-stage couplers. Using this system Laue transmission diffraction patterns of single crystals and powder patterns of polycrystalline aggregates have been obtained with exposure times of 30 nanoseconds.

The Powder Diffraction File (PDF), published by the JCPDS-International Centre for Diffraction Data, is one of the most widely used scientific data bases. It currently consists of about 40,000 x-ray diffraction patterns, organized into 32 sets and 5 subfiles: metals and alloys, minerals, common phases, forensic patterns, and those from the National Bureau of Standards (NBS), New patterns are being added to the PDF at a rate of 2,000 patterns per year. The sources of these patterns are the literature, private contributions, grants in-aid projects, and the JCPDS Associateship at the NBS.

Improvements in x-ray tube technology for the low-power tubes used in energy-dispersive XRF systems can provide better performance. These improvements are occurring in six areas: thin-window tubes, lower kV capability, higher kV and mA capability, pulsed tubes, smaller focal spots, and miniaturization. These improvements will lead to better excitation of the light elements, analysis of low-mass samples, higher count rates, small spot analysis, and smaller systems.

Machined parts made of fine ceramics are usually finished by grinding (Yajima et al.,1990, Mishima et al.,1987). The residual stress introduced by grinding will influence the fracture strength and the function of ceramics, and needs further consideration. Over the past few years, a considerable number of studies have evaluated ground ceramics by means of the X-ray method. However, it is well known that X-ray stress measuring data, 2 θ φ φ-sin2 φ curves of the surface layer of the unidirectionally machined ceramics are showing non-linear behavior (Kishimoto et al.,1987) . In this case, the sin2 φ method is inadequate for the evaluation of the stress (Sasaki et al.,1989).

An adapter for a standard Norelco spectrographte attachment will be described which permits the examination of a selected area of the specimen by X-ray fluorescence analysis. The size of the area can be varied depending upon the choice of pinholes with sizes available dovwi to 0.010 in. or 250μ. The sample is placed into a specially modified sample holder so that it can be moved at orthogonal directions under the beam from outside the spectrograph while the sample is under X-ray irradiation. Dam on applications will also be given.

Accurate phase characterization of the alteration products of rad-waste requires the separation and identification of scattered individual grains from among the bulk product. These grains are typically 5 to 100 μm in size. Bulk x-ray powder diffraction will normally not detect these minor phases, and even if the phase can be detected, it often may not be identifiable. The use of the Gandolfi technique with the individual particle not only facilitates the identification, but also allows the assignment of the identification to the specific grain.

Total reflection X-ray Fluorescence (TXRF) has been applied to the detection and quantification of metal contamination on the surface and near-surface regions of silicon wafers in the semiconductor industry The need for improving the sensitivity and detection limit of the TXRF technique is driven by the progress in producing thinner films and finer features in the development of larger Mbit DRAMS.

In the microprobe, lead stearate decanoate multilayer analyzers have proven to be practical components for X-ray spectrochemical analysis of the light elements. Better controlled techniques in the deposition of the layers have already produced analyzers yielding improved peak to background ratios as well as higher counting rates. Operational techniques, optimizing instrumental performance, will be discussed. Analytical data on the elements fluorine through boron, obtained with a modified commercial microprobe, will be presented.

The two general uses of proportional counters in X-ray analysis are discussed in the light of advantages and limitations inherent in the type of counter construction. Some effects on spectrographic results and industrial gaging are cited.

The use of grazing incidence parallel beam x-ray diffraction (GIXRD) in the characterization of lead zirconate titanate (PZT) films is described. This tool has enabled us to depth profile the films. The transmission electron microscopy (TEM) results obtained from a cross section of one film are shown to compliment the GIXRD results. The variation in crystallographic structure versus depth in the film was the primary focus of this study.

The insults from three PZT films having Zr/Ti ratios of 25/75, 48/52, and 75/25 are given. TEM results are reported from the sample with a Zr/Ti ratio of 48/52.

The discovery of a very simple and useful relationship between the absorption coefficient of a particular element and the ratio of incoherent to coherent scattering by the sample containing the element is discussed. By measuring the absorption coefficients for a few elements in a few samples, absorption coefficients for many elements in an entire set of similar samples can be obtained.

The x-ray spectroscopy of laser-generated plasmas can be applied to photon energies of less than 1 keV, provided calibrations of the response of energy discriminators and detectors are performed in the sub-kilovolt region. In our application we use photographic film to monitor the intensity of radiation dispersed by a curved lead stearate crystal. We have determined the response to sub-kilovolt x-rays of two types of film, Kodak No-Screen and the special vacuum ultra-violet Kodak type 101-01. This calibration was obtained by exposing samples of film to continuous beams of nearly monochromatic characteristic radiation from an array of targets. The fluorescent radiations were the K series of carbon and magnesium and the L series of titanium, nickel, cobalt and copper. The response data are presented as a series of characteristic curves, plotting for each film type and photon energy the net diffuse photographic density as a function of the photon flux incident on the film. The processing of all film was in accordance with the manufacturer's suggestions. We attempt to characterize the accuracy and reproducibility of these data. The data demonstrate the greater sensitivity of the type 101-01 to sub-kilovolt x-rays.

The intensity and spectral purity of the incident fluorescent beams were monitored by a thin-window gas proportional counter that used flowing propane gas at sub-atmospheric pressures. We describe the procedures and results of a determination of the quantum efficiency of this counter as a function of photon energy.

The salts of hydrazine or methyl derivatives of hydrazine were prepared by neutralization of the base with inorganic acids, for instance, HBF4, HClO4, H SO4, and HCl. Upon recrystallization of the product from a suitable solvent, X-ray diffraction patterns were obtained. Hydrazine tetrafluoborate H2N-NH2·HBF4 was found to crystallize in the monoclinic system. Cell dimensions and possible space groups were determined. The corresponding perchlorate salt crystallizes in two forms, one of which is isomorphous with hydrazine tetrafluoborate. The second form seems to be stabilized by small amounts of water.

The tetrafluoborate salt was prepared from the 1,1-dimethyl hydrazine. It was found to crystallize in the tetragonal system with a primitive unit cell. The perchlorate salt of this base is isomorphous with the fluoborate but with a slightly larger unit cell. Both materials undergo plastic-like deformation. The general appearance and mechanical properties are similar to those of a hydrocarbon wax. The 1,1-dimethyl hydrazine sulfate and the 1,1-dimethyl hydrazine hydrochloride have a lower symmetry than the HBF4 salt and do not show the wax-like properties of the latter. Based on the study of these chemically related compounds an explanation is offered for the properties of 1,1-dimethyl hydrazine tetrafluoborate in terms of crystalline structure.