The physical principles giving rise to synchrotron radiation(SR), the facilities necessary to make use of this source of radiation and the way in which it can be used for x-ray diffraction experiments have been described in other parts of this proceedings. The use of synchrotron radiation as an excitation source for x-ray fluorescence takes advantage of many of its unique properties to provide the potential for an improved analytical capability, beyond that which can be realized with more conventional laboratory x-ray sources. Workers around the world are studying this application (as well as a wide variety of others) , to establish the potential of this technique. Table 1 lists some of the facilities where significant XRF effort is being expended. This list is not intended to be complete, but just to convey some idea of the magnitude of the research which is being carried out.

Synchrotron X-radiation provides unique opportunities for diffraction experiments and, therefore, for extending our understanding of the structure - property interplay in catalyst systems. The present status of opportunities and applications of synchrotron X-ray diffraction techniques in the structural chemistry and catalysis science areas is overviewed, and illustrated by selected recent results.

The principles and techniques for performing coating thickness measurements in the laboratory and on-line using nuclear radiation have been established for tin or zinc coated steels. Recently, additional engineering efforts have been made toward the development of new coating substances consisting of complex layered materials. For example, zinc-iron alloy metal has higher corrosion resistance than pure zinc-coated steel sheets and evaluations have been made of beneficial characteristics in automobile production processes, such as easy welding, good paintability, high efficiency for press plastics forming, etc.

The demand for on-line analyzers capable of compositional determinations in petroleum and chemical process streams has increased dramatically in recent years. Total control of production plant processes and resources requires the analysis of feed, intermediate, and product materials. This paper will describe a rugged, on-stream energy dispersive X-ray fluorescence (EDXRF) analyzer configured for the continuous determination of composition in solid and liquid samples. The detector in the X-ray sensor is a lithium-drifted silicon crystal which is thermoelectrically cooled (Peltier effect) to achieve operational temperatures. This approach to detector cooling offers advantages over traditional cryogenic liquid cooling when EDXRF is used in the process control environment.

Three applications of the thermoelectrically-cooled detector-based EDXRF spectrometer will be presented here. The first is the analysis of a catalyst solution to monitor depletion of the active species. Second, two components of a plating bath solution will be determined simultaneously in a flowing sample stream. In the third application, the spectrometer will be oriented in a downward looking configuration to monitor inorganic constituents in absorbent samples as they are transported by conveyor belt to the X-ray measurement area.

X-ray fluorescence analysis (XRF) is an analytical method which has been adapted with considerable success to on-line industrial process analysis with various degrees of sophistication. Process analysis XRF systems range from relatively simple units utilizing radioisotope sources with non-dispersive analyzers to complex wavelength dispersive systems in a central location receiving samples from a number of process streams. The advantages of on-line process analytical instrumentation for quality control, regulatory 2 compliance and safety considerations are well documented. ' Advances in the development of low maintenance thermoelectrically cooled Si(Li) detectors have made energy dispersive X-ray fluorescence analysis (EDXRF) even more amendable to on-line process analysis. EDXRF is an important method of on-line instrumentation because of its ability to simultaneously detect many elements.

A modern metal-ore flotation process requires a continuous instrumental measurement of the metal content in main flotation streams. X-ray fluorescence technique is most often used for on-stream analysis of metal-ore slurries,1 Especially the radioisotope energy-dispersion XRF (REDXRF) method provides the possibility of using measuring probes immersed in the slurry at the point of analysis. The main advantage of this technique is the elimination of the necessity to transport the slurry to a control laboratory which houses the X-ray spectrometer.

Temperature, pressure, and flow measurements are considered standard for process control purposes. It is vital that they be made on-line in real-time and not manually in the laboratory. Chemical assays should be done as fast and continuous as temperature measurements in order to be useful for process control. Until recently, this has not been the case because the assay methods have been difficult to automate.

X-ray fluorescence (XRF) has been successfully used for more than 20 years as an on-line analysis method for controlling various industrial processes where the concentrations of different elements must be known in the process streams. In many industrial processes, however, the knowledge of the concentrations of different minerals, rather than those of the elements, is of prime importance. Examples of such processes are numerous; plants concentrating apatite for fertilizer and detergent manufacturers, paper filler producers manufacturing kaoline, titanium dioxide (rutile) and talc, potash concentrators and different crystallization processes.

It will be shown that there are different types of influence coefficients to correct for matrix effects in XRF analysis: the empirical coefficients calculated from regression analysis and valid for the standards on hand only; the theoretical binary coefficients that are essentially constant in a given concentration range; then the theoretical multi-element coefficients calculated from one given composition and valid for one specimen only.

With theoretical coefficients, however, a special calibration process is needed, because theory cannot take into account all the instrumental parameters. In the proposed calibration method it will be shown that the slope of the calibration curves is the link to correlate the theoretical formalism to the experimental reality; that the standards used do not have to be similar to the unknowns and that a few only are required; that the calibration curves can be extrapolated by a factor of two or three; that pure analytes are not required.

A new computer program, named CiROU, has been written to determine the chemical composition of homogeneous samples analyzed by X-ray fluorescence spectrometry (XRF). It uses the furdamental algorithm to convert measured intensities into concentrations anc to correct for matrix effects and runs on any IBM-PC/XT/AT, PS/2 or compatible corrputer.

The program is very easy to use mainly because it is a step-by-step guide to the routine process of analyzing specimens by XRF and because a user friendly interface makes up a main menu bar containing six major options, which provide several other options inside a pull-down window system.

The program is applicable to specimens of any composition with the utmost accuracy that can be obtained from the fundamental-parameters method. It’s unique calibration procedure still adds to the accuracy by eliminating the bias between theory and reality.

The program is a complete “off-line” program allowing to perform all the steps of an XRF analysis: calculation of theoretical influence coefficients, calibration, reading of measured intensities, calculation of net intensities and concentrations of unknowns, print-out of analytical reports and data transmission to or from an external computer.

In the spectroscopic analysis of minor and trace elements by fluorescent X-rays, many improvements in the analytical performance of trace element measurements have been made. For the analysis of trace elements, the background intensity governs the analytical accuracy and the lowest detection limit in a sample. A comparison is made between experimental and theoretically calculated background X-ray intensities in a previous paper. It is based on the formula for scattered X-ray intensity, from the estimation of Thomson and Compton scattered X-rays. Also, the asymmetrical peak profiles at the base of the giant intensity peak are discussed and are clearly shown in the skirt part of K beta X-rays, e.g. , Ni-K beta or Fe-K beta X-rays. The purpose of this report is to investigate the intensity of background X-rays, using glass beads and powder samples of iron oxide and quartz, based on the previous fundamental studies and the overlapping correction procedure for cobalt determination in low-alloy and stainless steel.

In 1985 Nichols and Ryon [1] first demonstrated their x-ray microfluorescence analysis (XRMF) system. By 1986 Nichols et al. [2] Boehme [3] and Gurker [4] provided us with spectacular photographs of x-ray images of geological materials, wire grids, and semiconductor chip carriers. During the delivery of the paper by Nichols et al. [2] the present author realized that a higher degree of spatial resolution could be accomplished by analysis of the raw data.

This paper describes the principle, method and application of the proportional factor method for the determination of rare earth elements (REE) in geological samples by XRF, The analytical results of this method are compared with REE recommended values in geological standards, and good agreement was observed. Five of the REE (Pr, Tb, Ho, Tm and Lu) have also been determined by interpolation from chondrite-normalized plots, and more satisfactory results were obtained.

The total reflection of X-rays is mainly determined by three parameters , that is the orltical angle, the reflectivity and the penetration depth. For X-ray fluorescence analysis the respective characteristic features can be exploited in two rather different fields of application. In the analysis of trace elements in samples placed as thin films on optical flats, detection limits as low as 2 pg or 0.05 ppb, respectively, have been obtained. In addition, a penetration depth in the nanometer regime renders Total Reflection XRF an inherently sensitive method for the elemental analysis of surfaces. This paper outlines the main physical and constructional parameters for instrumental design and quantitation in both branches of TXRF.

A laboratory-based X-ray microprobe, composed of a high-brilliance microfocus X-ray tube, coupled with a small glass capillary, has been developed for materials applications. Because of total external reflectance of X rays from the smooth inside bore of the glass capillary, the microprobe has a high sensitivity as well as a high spatial resolution. The use of X rays to excite elemental fluorescence offers the advantages of good peak-to-background, the ability to operate in air, and minimal specimen preparation. In addition, the development of laboratory-based instrumentation has been of Interest recently because of greater accessibility when compared with synchrotron X-ray microprobes.

It Is not practical to connect each controllable function of a WDXRF (Wavelength Dispersive X-Ray Fluorescence) spectrometer separately to the laboratory computer. Therefore, a spectrometer controller is used to interface with the hardware control actuators which operate the selectable or settable components of the spectrometer system. The basic function of a controller is to receive sequences of orders from the computer and transmit the data which has been collected. More advanced controllers, such as the one used in the Siemens SRS-300 spectrometer, may perform many additional functions. In addition to handling spectrometer-to-lab computer communication, the SMP (Siemens Microprocessor controller) is capable of monitoring the state of the instrument, resolving conflicts in external or internal requests for action, and terminating spectrometer action which can be seen as hazardous or damaging to the instrument.

X-ray fluorescence spectrometry has been used in a broad spectrum of applications. These include elemental analysis, both qualitative and quantitative, based on wavelength dispersive (WDXRF) or energy dispersive (EDXRF) methods. In these methods the detection limit of analyte elements is mainly in the one to ten ppm range in solid samples. Therefore, improvement of these limits is desirable for many useful applications. In this context it is essential to remember that the excitation efficiency for fluorescent X-rays is very low when compared with electron or proton excitation. In the case of WDXRF, the dominant factor is the low reflectivity from the analyzing crystal.