The concept of fractals (or fractional dimensions), although known earlier, was formalized theoretically and given that name in 1967 by Mandelbrot. A fractal is some object, whether mathematically constructed or observed in the physical world, that exhibits scale in variance—that is, it looks essentially the same at all scales, or over some range of scales. Objects that exhibit fractal geometry and that are measured in the same units in both the x and y directions are said to be self-similar; geologic examples of self-similar fractals are a rocky coastline and a topographic contour, for which the east-west and north-south coordinates of any point are expressed in, say, meters or kilometers. Objects that exhibit fractal geometry but which are measured in different units along x and y are said to be selfaffine fractals; an example of a self-affine fractal is a topographic profile, in which the horizontal dimension is measured in kilometers and the vertical dimension is measured in meters.

A program was developed to predict d-spacings and intensities for peaks of binary phases, using data of the stoichiometric compositions as a basis, and was extended for ternary systems. Predicted data were compared with results from a series of alloys in the Ni-Ru-Al system, spanning the system near 50 atomic % aluminum, to ascertain the extension of the RuAl and NiAl intermetallic compounds into the ternary system. The microstructures mainly appeared cored, and one sample was single phase.

The program enabled easy identification of the peaks, and also allowed comparison of experimental data with predicted ordered and random spectra.

Total reflection x-ray fluorescence analysis (TXRF) has reached a mature state but still improvements are possible in selecting the proper components for TXRF and optimizing them in the best suitable way. Two approaches are presented, the extension of the number of detectable elements after K-shell excitation and the improvement of the detection limits. The results show, that the elements from B to U can be detected by their characteristic K-lines and that detection limits for medium Z elements e.g. Ni in the fg range are achievable. Most of the best results have been measured using synchrotron radiation with spectral modifying devices like multilayer monochromators. Other x-ray sources like a windowless tube with exchangeable anodes of either material Al, Si or Mo were successfully tested for the efficient excitation of light elements.

Standards organizations active in surface analysis using TXRF and VPD/TXRF include: (a) American Society for Testing and Materials (ASTM), (b) Semiconductor Equipment and Materials International (SEMI), (c) Ultra Clean Society of Japan (UCS), and (d) International Standards Organization Technical Committee 201 (ISO TC/201). The standards activities are presently dynamic, and they are on an international scale, This paper provides an update on the status of these activities, and presents the challenges ahead yet to be resolved.

Total Reflection X-ray Fluorescence Analysis (TXRF) has been proved to be well suited for the energy dispersive analysis of light elements, as B, C, N, O, F, Na, Mg,.,. using a special spectrometer. It is equipped with a Ge(HP) detector offering a sufficient detection efficiency from 180 eV upwards. The obtainable detection limits especially of the light elements are mainly influenced by the excitation source, which should provide a large number of photons with an energy near the K-absorption edge of these elements (from 200 eV upwards). Commercially available X-ray tubes do not offer characteristic X-rays in that range. In former experiments a windowless X-ray tube was built to prevent the low energy X-rays from being attenuated in the Be window. Experiments have been performed using Cu as anode material.

Over the past few years there has been substantial progress in the TXRF analysis of heavy element surface contamination on silicon wafers. Further advances and improvements are desired in the analytical performance and hardware. Extension of the analytical range to include the light elements is particularly desirable.

In the case of light element analysis, sodium and aluminum impurities have been monitored in the IC production process. The increase of the sodium impurity in a silicon wafer gives rise to a decrease in the insulation in IC devices and the growth of the SiO2 film is disturbed by the prsence of aluminum impurity on the silicon wafer surface.

In TXRF analysis of impurities in Si wafers, one of the analytical problems is the separation of the peaks of interest (e.g., fluorescence peaks from Fe or Cr) from various background artifacts. These background artifacts include (a) a large Si Kα fluorescence peak, (b) a large peak from the scattered and diffracted primary beam (e.g., W Lβ), (c) a continuum background, (d) scattered radiation in the vicinity of the primary beam peak, (e) an escape peak from the primary beam peak, and (f) spurious Fe and Ni peaks from the detector. This paper will present a scheme for the separation of these components using a fitting procedure based on a commercial spreadsheet.

A new sample support film for small spot XRF analysis has been developed that improves detection limits by a factor of 10 over traditional polymer supports. The surface characteristics of this new film are excellent for retaining drops of sample solution in one place and allowing the solution to dry into a single spot A dimpling technique was developed to further aid in concentrating the evaporated samples to the prescribed spot size and position. The film showed good resistance to chemical attacfc from the solution, even some strong acids and bases. The detection limits achieved using micro sample XRF with the ultra thin sample support were sufficient to be a comparable alternative to ICP-MS and GFAAS for elemental analysis.

The electronic spreadsheet market for the IBM or compatible PC has become competitive. One can find a dozen or more different spreadsheet programs available today which are very nicely graphically “dressed,” Computer journals indicate that the main spreadsheet competitors.

The fundamental approach to calculating the chemical element content resulting from x-ray fluorescence measurements has been substantiated theoretically. The elaboration of the calculation algorithm has proved the physical-mathematical model for the x-ray fluorescence intensity arising from photon irradiation and spectrometry peculiarities.

Special attention has been put on the real processes, in these elaborated algorithms. They take into account all the valuable effects influencing the x-ray fluorescence intensities, as well as the. stability of the equipment measurements. The results of some applications are shown.

We report on results obtained from experiments using specially prepared carbon substrates and treatment of the data by means of recently introduced theory. Medium Z grids with known parameters have been coated on top of pyrolytic carbon substrates to achieve well defined absorption geometries. The various copper grids exhibit satisfactory performance in terms of mechanical stability, homogeneity and uniformity of the coating. A detailed study of the measurement results shows that there is a more rapid increase of the associated C-Kα countrate from the coated samples compared to the pure elements and is attributed to the contribution of secondary enhancement effects, including those resulting from photoelectrons generated after the primary ionization.

X-ray valence band emission spectroscopy (XES) is one of the oldest method used for studying the electronic structure of compounds. During the last three decades the rapid development of photoelectron spectroscopy (XPS, UPS) and the use of these techniques for studies of electronic structure has diverted attention from XES, However, interest in XES has been revived recently as a result of progress made in the experimental technique and the availability of the synchrotron radiation. An important advantage of XES is that, in compounds, this technique projects the density of states (DOS) at the site of emitting atom. To our knowledge, in spite of broad interest in studies of the electronic structure of diluted magnetic semiconducting (DMS) crystals, XES was not applied to this problem. In this work, we present the first measurements of the L-emission spectra of ZnS doped with Co. The partial substitution of the Zn-cations by magnetic Co atoms results in hybridisation of the 3d-states of Co with sp band of the host semiconductor.

An essential problem in X-ray fluorescence analysis is the derivation of a correct analytical expression relating the X-ray fluorescence intensity to the excitation radiation, the experimental geometry and the sample composition. Theoretical formulae have been derived only for evaluation of the average value of the fluorescence X-ray intensity. As far as known by the authors, no theoretical considerations concerning probability density function of the X-ray fluorescence intensity have been applied.

K, L and M shell x-ray fluorescence cross sections have been measured for elements 11 ≤, Z ≤, 92 at excitation energies corresponding to weighted average energies of K-lines of Ti-K (4.558 keV), Fe-K (6,480 keV), Ge-K (10.024 keV), Se-K (11.391 keV) and Mo-K (17.805 keV) . The measurements were performed with an energy-dispersive x-ray spectrometer in a vacuum chamber using thin ultra-pure targets. Rh x-ray tube and secondary targets were used for excitation of x-ray radiation. The measured x-ray fluorescence cross-sections have been compared to previously published experimental and theoretical results. Presented data can be used for determination of physical parameters such as photoionization cross-sections, fluorescence yields, x-ray emission rates, Coster-Kronig transition probabilities and jump ratios.

Different analytical methods can be applied to the analysis of the chemical composition of archeological artefacts. The methods presently used to examine archeological artefacts include: emission spectrometry, atomic absorption spectroscopy, x-ray fluorescence spectrometry and neutron activation. The use of these techniques is limited by several factors such as: the size of a sample that can be taken from the object, the availability of the method in the sense of easy access, and the cost of and time spent for the analysis.

A feasibility test at the Naval Research Laboratory has shown that a miniature X-ray Fluorescence (XRF) sensor can be constructed for the cone penetrometer. Such a sensor would have detection limits for heavy metal contaminants in soils of a few parts per million. The next step is to demonstrate the capabilities of such a sensor in the cone penetrometer. A sensor for this purpose is being constructed and will be tested both in the laboratory and in the field. The XRF sensor will be capable of evaluating the in-situ detection limits and field screening (semi-quantitative) capabilities of x-ray fluorescence and can be transitioned to field activities for further evaluation and feedback. The sensor will consist of a miniature x-ray tube and an x-ray detector, together with appropriate apertures and x-ray filters, in a custom fabricated section of penetrometer pipe. The sensor will use commercially available components. High voltage and signal cables will couple the sensor to electronics in the truck. Boron carbide will be used for the x-ray windows which protect the sensor components from soil abrasion.

The Metropolitan Police Forensic Science Laboratory is faced from time to time with cases which require the detection and estimation of metals in biological matrices. These cases generally concern instances, allegations or threats of poisoning and require the analysis of either foodstuffs or body fluids, or both. The elements of particular interest are antimony, arsenic, bismuth, cadmium, lead, mercury, and thallium.

Polypropylene windows stretched to 1-1.5 μm in thickness have been traditionally used for soft x-ray detection on gas flow proportional counters. Theoretical calculations show that significant transmission Improvement could result from a thinner window. The trade-offs to ultimate transmission have traditionally been reliability and durability. A 0.3 um window has been fabricated to show significant improvement for light element transmission, A supporting grid was used to back the film and provide additional support and durability to allow for pressure cycling during venting of the spectrometer chamber. Significant transmission improvements were observed for ultra soft x rays in the energy range below 1 KeV.

This paper investigates the diffusion of Pt into polycrystalline thin-film BaxSr1-xTiO3 synthesized by sputter deposition and metal-organic deposition (MOD). Comparison of these two sets of films demonstrated that no remarkable interdiffusion was observed at the Pt/BSTO interface for the sputtered films. This is contrary to the films prepared by MOD which shows Pt has thoroughly diffused into BSTO films. The deeper diffusion of Pt into BSTO films prepared by MOD is attributed to die microstructure of these films. The effects of die diffusion on some physical properties have been discussed. Moreover, the effect of the heat-treatment on the diffusivity and other parameters is discussed