The Shared Research Equipment (SHaRE) User Facility and Program at Oak Ridge National Laboratory (ORNL) provides microanalytical facilities for studies within the materials sciences. Available instrumentation includes advanced analytical electron microscopes, atom probe field ion microscopes, and nanoindentation facilities. Through SHaRE, researchers from U.S. universities, industries, and government laboratories may collaborate with Facility scientists to perform research not possible at their home institutions. International collaborations are also possible. Most SHaRE projects seek correlations at the microscopic or atomic scale between structure and properties in a wide range of metallic, ceramic, and other structural materials. Typical research projects include studies of magnetic materials, advanced alloys, catalysts, semiconductor device materials, high Tc superconductors, and surface-modified polymers. Projects usually involve one or more external researchers visiting the SHaRE Facility for up to three weeks during the fiscal year (October 1 - September 30). Project approval is based upon the scientific excellence and relevance of proposed collaborative research.

A standard Philips CM200FEG electron microscope, without the special Lorentz lens, has been optimized for Lorentz imaging. The necessary field-free sample region is obtained by switching off the objective lens in the free lens mode. The limited range of magnification is compensated for by a post-column Gatan image filter (GIF) which magnifies by a factor of _ 20. Fresnel imaging is performed by defocusing with the diffraction lens. The use of low angle diffraction, in combination with the apertures located at the selected area aperture plane, allow Foucault imaging. The TEM analog of differential phase contrast (DPC) imaging has been implemented. This method makes it possible to obtain quantitave induction maps of the in-plane magnetization. TEM DPC is based on a series of Foucault images, recorded with different incremental beam tilts, which are processed to yield images equivalent to the quadrant signals obtained by the STEM DPC technique.

Five applications of analytical light microscopy to problem-solving in the pharmaceutical industry are described and illustrated by case examples. Problems included are (1) the caking of pharmaceutical products, (2) chemical incompatibility, (3) nucleation and precipitation, (4) recognition of hydrates and polymorphs, and (5) identification and sourcing of contaminant particles.

Considerable effort goes into the sizing of solid pharmaceutical raw materials and products. In many instances, particle size is used to help control the rate and uniformity of dissolution, which in turn affects the kinetics of drug delivery. Caking is a macroscopic description of the change in a sample from a finely-divided powder to a single solid molded aggregate. Caking obviously has a severe impact on handling and dissolution characteristics.

Caking of a powder is almost always caused by moisture through the cyclical dissolution and precipitation on the surfaces of the particles. When exposed to sufficient vapor pressure, often through changes in humidity or temperature,

Several case studies are shown as examples of the results of analyses using various microscopical instruments to characterize the particles in building dusts. Characterizing the particles and identifying possible sources of particles in dusts are often important parts of solving indoor indoor air quality (IAQ) and environmental problems. Samples of the dust particles can be collected by filtering the air with cassette air filters or by gathering the dust that has accumulated on surfaces. Depending on the size and types of particles in the dust either polarized light microscopy (PLM), scanning electron microscopy with x-ray analysis (SEM/EDS), analytical transmission electron microscopy (ATEM) or Fourier transform infrared microspectroscopy (FTIR) may be used solely or in combination. PLM can characterize most of the common dust particle in residential and commercial buildings. SEM/EDS is helpful in identifying metal particles and when used in the backscatter electron mode, a large number of particles can be surveyed and those containing heavy metals such as lead and cadmium can be identified quickly.

Many different microscopic techniques are utilized in the development of new pharmaceuticals. For that reason, pharmaceutical companies have supported microscopy and microscopists even in the face of retrenchments in many other industries. Microscopy has the following three major uses in pharmaceutical development: 1) solid-state characterization of drug substance; 2) particle size analysis; 3) contaminant identification. Microscopy is also an important component of the study of the biological activity of drugs but that subject will not be discussed here.

The analysis of the solid-state properties of new drug candidates is probably the most important and challenging subject of study for pharmaceutical microscopists.1 The primary objective of these studies is identification of the most suitable solid-state form (i.e. polymorph, solvate, hydrate) of the drug substance for development. Polarized light microscopy (PLM), thermal microscopy (TM), infrared microspectroscopy (IR), and Raman microspectroscopy (RM) are all utilized in these studies. Both PLM and TM are used to discover new polymorphs and solvates of the chemical.

A BNL-Grace process has been developed to chemically convert in-situ, the chrysotile fibers of sprayed-on fireproofing products to an unregulated glassy material. The effectiveness of this process has been convincingly demonstrated using Analytical Electron Microscopy and X-Ray Diffraction techniques.

Asbestos minerals were used in fireproofing materials because of their excellent physical properties including fire resistance, high tensile strength, heat and electrical insulation, and resistance to acids and alkali. But in 1975 the Environmental Protection Agency began regulating materials containing > 1% asbestos.

The new in-situ BNL-Grace process, which uses a foamy solution sprayed directly onto asbestos-containing fireproofing chemically digests essentially all the asbestos fibers, transforming them into harmless materials. After treatment, the fireproofing is no longer a regulated material. The process produces essentially no waste.

Our problem was to demonstrate that all of the asbestos was converted and that the remaining materials were no longer regulated. Typical analysis methods use conventional optical and Polarized Light Microscopy (PLM) to measure and observe fibers.

During the past twelve months RJ Lee Group has manually collected and published over one hundred thousand composite SEM images consisting of three components: a low magnification image, a high magnification image, and an x-ray spectrum. In addition, about one and one-half million discrete features have been automatically located and compositionally/morphologically characterized, with about one-fourth of those features then having ancillary images collected automatically based upon characterization criteria. Finally between ten and twenty thousand images have been collected for the production of image montages. The output of this effort has been systematically entered into networked databases where it is accessed for post-processing, analysis, and report generation.

Titanium is used in the manufacture of AISI 316L austenitic stainless steel as a deoxidizer. Titanium is considered a residual element, and limits are often not specified. As a residual element, titanium most often appears in complex oxide inclusions, usually in conjunction with aluminum and other deoxidizers. Titanium-bearing inclusions have been found to initiate pitting during electropolishing. The present work was performed to evaluate the acceptable upper limit for titanium as a residual element in AISI 316L.

Metallographic specimens were prepared from seven commercial heats of AISI 316L (Table 1) with titanium contents varying from 0.003 % to 0.014 %. A quantitative metallographic analysis of each specimen was performed using an SEM/EDS system with an automated stage. Operating parameters are given in Table 2. Data was obtained with the system in the backscatter (BS) mode, producing a high-contrast image based on differences in chemical composition. Once each inclusion was identified by its difference in gray scale, it was also analyzed by EDS for elements present.

This paper addresses the microanalysis techniques used to characterize thermal sprayed Ti coatings on concrete surfaces as anodes in impressed current cathodic protection (ICCP) systems. Thermal sprayed Ti anodes on concrete were electrochemically aged in laboratory studies of anode performance and service life. A thermal sprayed catalyzed Ti anode was installed on the Depoe Bay Bridge on the Oregon Coast in a field demonstration of the ICCP system. Both air and N were used as the atomizing gases during the study. Thermal sprayed Ti coatings are typically applied in an inert atmosphere or vacuum using shrouds or chambers to prevent reactions with the atmosphere. This was not possible with a structure as large as a bridge.

Microanalysis of Ti and N together is difficult and the effects of O add to the complexity of the analysis. The ternary Ti-O-N system has not be well studied.

The layer sequence of multi-layered white and off-white paint chips usually encountered by the forensic scientist in cases involving structural and/or maintenance paint is sometimes difficult to discern when utilizing commonly employed microscopical methods. This layer sequence information becomes vitally important when comparing a questioned paint sample to a paint sample of known origin. Techniques such as reflected light microscopy, fluorescence microscopy, and scanning electron microscopy (SEM) coupled with energy dispersive x-ray spectroscopy (EDS) may not provide the needed discrimination. Also, binder information may not be available for comparison since the thinness of the layers the difficulty in detecting individual layers, and the abundance of the extender pigments may preclude analysis by infrared microspectrophotometry.

Cathodoluminescence microscopy (CLM) may provide the needed layer sequence information and discrimination when analyzing and comparing multi-layered white and off-white paint samples. Cathodoluminescence (CL) is the emission of radiation from the sample in the visible light region and neighboring wavelengths during excitation by electrons generated from a cathode electron gun.

Microscopy is of vital importance in the real world of the forensic scientist. In today's society, physical evidence is critical to the criminal justice system for the detection, investigation and prosecution of criminal acts. A trail of microscopic fibers led investigators in Atlanta to the conviction of the serial killer, Wayne Williams. Flecks of paint on a hit-run victim, analyzed microscopically, can be compared with the paint on a suspect vehicle to exclude or match it to the crime. The forensic firearms examiner compares the microscopic striations on a bullet to match it to the gun it was fired from. Microscopes are used throughout the modern forensic laboratory. They are essential in searching for evidence. They aid the examiner in identifying and comparing trace evidence. As the scales of justice symbolize forensic science, microscopes symbolize the trace evidence examiner.

Because of the variety of physical evidence, forensic scientists use several types of microscopes in their investigations.

Focused Ion Beam or FIB systems have been used in integrated circuit production for some time. The ability to combine rapid, precision focused ion beam sputtering or gas-assisted ion etching with focused ion beam deposition allows for rapid-prototyping of circuit modifications and failure analysis of defects even if they are buried deep within the chip's architecture. Inevitably, creative TEM researchers reasoned that a FIB could be used to produce site specific parallel-sided, electron transparent regions, thus bringing about the rather unique situation wherein the specimen preparation device often was worth as much as the TEM itself.

More recently, FIB manufacturers have concentrated on improving the resolution and imaging characteristics of these instruments, resulting in a more general-purpose characterization tool. The Micrion 2500 FIB system used in this study is capable of 4 nm imaging resolution using either secondary electron or secondary ions, both generated by a 50 kV liquid metal gallium ion source.

Photographs of x-ray transmission images by x-ray films have been used for observing the inside nondestructively. Further, Imaging Plates(IP) are used for precise measurements of x-ray diffraction patterns. But, these integrating area detectors are not suitable for real time nor time resolved measurements. For real time and time resolved measurements, the X-Ray Image Intensifier(XRII, a large image tube that converts an x-ray image into a visible image) is used for biological x-ray TV systems, x-ray nondestructive inspection systems etc. These TV x-ray image systems require high energy x-rays, x-ray tube voltage of 30 to 150 kV, and show faint contrast for x-ray images of light element substances owing to its low absorption coefficients. However, light elements have intense x-ray absorption coefficients in a low energy x-ray region, x-ray tube voltage of 5 to 20 kV, and give fine contrast for x-ray images of light element substances.

Exploratory synthetic strategies may yield limited quantities of sample. Characterization of such limited-quantity samples is facilitated by the use of sensitive analytical methods and smart sample preparation. Polymers may be analyzed by mass spectrometry for molecular weight distributions, structural information (such as endgroups), and impurities. However, polymer research using mass spectrometry has not focused on detection limits; in some work the amount of polymer used is not even mentioned. Studies to determine detection limits of polymers and studies that characterize sample preparation techniques can provide valuable information.

Examination of the sample surface on a probe tip, generated by the use of an aerospray technique for sample deposition, was accomplished by scanning electron microscopy (SEM). Aerospraying the polymer and matrix solutions allowed signal averaging of mass spectra from up to 400 shots on the same sample spot. SEM images showed the surface of the probe to have a fairly uniform coating of the sample and matrix.

Transport, cleanup, and bioremediation properties of polychlorinated biphenyls (PCBs) bound to sediments depend on the specific components to which the PCBs are bound. Analysis of the sediment from Contaminant Cove on the St. Lawrence River by gas chromatography with an electron capture detector shows that the sediment contains 600 ppm PCBs. Previous work showed that there were both weak and strong binding of PCBs to sediment components, but gave no indication of which components were responsible for the binding.2 The average content of PCBs is below the limit of detectability by energy-dispersive x-ray microanalysis (EDX) for CI, but constituents which bind large quantities of PCBs could be detected. Sediment which is not contaminated with PCBs contains no detectable chlorine.

EDX analysis was performed on a JEOL JEM-4000FX, using a cryo-stage (operated at -160° C) and a Tracor TN5500 system.

Protection of public health requires routine monitoring of environmental waters for fecal contamination, especially waters serving as drinking supplies. Municipalities typically rely on assays of indicator microorganisms to detect fecal contamination. Ideally, indicators and pathogens share a common origin. However, the indicators should have higher numbers, survive longer, and be easier to detect and quantify in the laboratory than pathogens. Coliform bacteria are the standard microbial indicator currently used in the United States. Enteric viruses are smaller and survive longer than coliform bacteria, therefore they are inadequate indicators of enteric viruses. Enteric bacteriophages, viruses infecting bacteria, may be a more reliable indicator for human viral pathogens. However, there are several taxonomic groups of enteric bacteriophages, all of which may not be good virus indicators. This project examines the ecology of coliphages, bacteriophages infecting Escherichia coli, in a ground water aquifer which serves as a municipal water supply.

Volcanic eruptions inject tons of silicic material into the atmosphere. Large, dense material falls out within a few hours whereas fine size fractions, < 10 μm radius ash, may remain airborne for weeks to months. Protection of human population centers and aircraft requires predictive atmospheric transport models. Many of these models assume the ash particles are spherical but abundant qualitative studies of ash particles demonstrate irregular shapes ranging from parachute-like bubble-wall shards to polygonal shaped mineral grains. These non-spherical shapes increase atmospheric drag. The accuracy of transport models may be improved with a better understanding of the actual shapes found in fine ash particles. Therefore, the objective of this study is to accurately determine three-dimensional shape measurements via stereoscopic methods using the scanning electron microscope.

The scanning electron microscope is an ideal imaging platform for collection of stereo pairs because of its utility in stereoscopic height measurement.

It has long been known that carbons have order at the microcrystalline level. Soots have been characterized as having a turbostratic structure and chars have been described as crumpled sheets. The value of electron microscopy in studying the morphology of such materials has been well established although only a few attempts have been made toward quantification.

The Methodology is based upon High Resolution Transmission Electron Microscopy (HRTEM) and further image analysis. The HRTEM image of each sample is recorded, digitized and processed with an image analysis software. Computer generated diffractograms are produced through Fourier Transformation and subsequent reverse transformation yields two color ‘extracted structures’ (Figure 1). The extracted structure is then undergoes statistical analysis. The analysis is aimed at identifying quantifiable structural parameters. Currently the following parameters are studied: circularity (C), elongation (E), and length of fringes (La) orientation of the fringes (cti), the inter-layer spacing (d002), and the fractional coverage of the extracted pattern (F).

Micro-Raman spectrometry and Mossbauer spectroscopy have been used to identify the corrosion products on a steel coupon exposed in an industrial environment for 16 years. The Raman analysis was performed on a polished metallographic cross-section in order to map the oxides across the thickness of the coating. The spectra were recorded using a LabRam Micro-Raman spectrograph incorporating a 17 mW HeNe laser (attenuated to 1 mW to prevent oxide transformation), focused to 1 μm spot size, and 1800 g/mm grating. The confocal line-scan imaging enabled 100 spectra to be recorded in one scan at 0.5 um intervals across the thickness of the coating. The Mossbauer analysis was performed using in-situ scattering Mossbauer spectroscopy on the attached corrosion coating and transmission Mossbauer spectroscopy at 300K and 77K on the removed coating, to measure the fraction of each oxide present. Micro-Raman spectrometry showed that the corrosion products had formed in distinct layers as shown in Figure 1.

In previous work with the Raman microprobe, we have examined the fluorescence emissions of rareearth (RE) bearing glasses to study the phenomena of structural resonances in the spectra of glass microspheres and the energy upconversion processes for RE ions in such glasses that give rise to anti- Stokes fluorescence emission. Presently, we are revisiting these same fluorescent glasses to study their laser excited emissions as potential radiometric sources for the calibration of Raman spectral intensities. Many of the rare earth ions produce interesting fluorescence spectra on laser excitation depending on the type of ordered or disordered (solid) host matrix. These fluorescence spectra, depending on RE concentration and quenching effects, can be intense and may consist of either narrow-band (or line) emissions or broad-band spectra covering a wide spectral range. These spectra, acquired at laser wavelengths from the ultraviolet (UV) to the near-infrared (NIR), provide a practical means for the calibration of Raman instrumentation for both Raman frequency and intensity.