Miniaturization of electron optical systems has gained much interest over the last decade [1,2]. In a scanning electron microscope, downscaling of the column dimensions is expected to allow for high resolution imaging at low electron beam voltage. Main advantages of low voltage imaging are lower penetration depth, increased secondary electron yield, less specimen charging and better topographic contrast [3].

We have developed a miniature scanning electron microscope (SEM) with high resolution at low beam energies. The outer dimensions of the miniaturized SEM column are 25 mm diameter and 95 mm length, including conventional field emitter electron source module. The column prototype is shown in Fig. 1. The size reduction has been achieved by the exclusive implementation of electrostatic column components. Electron optical simulations indicate that the retarding objective lens of the miniature SEM allows for a probe resolution of 3 nm at 1 keV beam energy. The secondary electrons are collected at an internal scintillator detector.

Self-assembled monolayers (SAM) and multilayers of organic materials have been intensely studied in the past years, due to their numerous potential applications as, for example, lubricants, corrosioninhibitors and/or adhesion-promoters [1,2]. Due to the reduced height of SAM, typically a couple of nanometers, the various Scanning Probe Microscopy (SPM) techniques, especially Scanning Tunneling Microscopy (STM) and Atomic Force Microscopy (AFM), have been the tools of choice in the morphological and structural study of those systems [1,2]. However, these SPM techniques have some limitations. One of them is the reduced scanning area, preventing the assessment of SAM coverage in large substrate areas, which is one of the key issues in studies of the potential applicability of SAM. Furthermore, due to their imaging principle, the SPM techniques are not suited to analyze SAM on substrates where the roughness is of the order of hundreds of nanometers or higher, impeding their application on most non-ideal (atomically flat) substrates.

Recently studies examining the colonization of Clostridial pathogens on agar and human tissue culture cells, demonstrated that (C. sporogenes ATCC 3584, C. difficile ATCC 43594 [patient isolate], C. difficile ATCC 9689 [non-clinical], C. clostridioforme [patient isolate]) bacterial spores (endospores) of the genus Clostridia have an outer membrane that becomes responsive at activation and exhibits extensions of the exosporial membrane that facilitate and maintain spore attachment to a nutritive substrate during germination and initial outgrowth of the newly developed bacterial cell. Therefore this attachment phenomenon plays an important role in insuring bacterial colonization of a surface and the initial stages of the infective process. To see if other non-clinical members of this genus also have this ability to attach to a substrate or food-source during spore germination, and how this attachment process in environmental thermophiles compares to the clinical paradigm (in relation to time sequence, exosporial membrane structure, type of attachment structures, composition of the membrane etc.), sediment samples were collected in sterile transport containers at 4 geothermal sites at Yellowstone National Park in Wyoming.

Research into bone histology of fossil material is a growing area of inquiry in vertebrate paleontology. Incorporating histological study into ontogenetic investigation presents new opportunities for gaining data to better understand ontogeny, ecology, and evolution of mosasaurs. Adding scanning electron microscopy to the growing technology being applied to fossil research can only further the understanding of long extinct animals.

Mosasaurs were totally marine lizards which inhabited both open ocean and epicontinental seas during the late Cretaceous (Turonian through Maestrichtian), approximately 90-65. million years ago. Mosasaurs have been collected from many areas of North America. The specimens used in this study were collected from Alabama, Kansas, South Dakota, and Texas. I have restricted the fossil material for destructive analysis to ribs and vertebrae. Ribs have not been shown to have importance in morphological analysis relating to systematics or evolution, therefore their destruction does not imped the research of others. Vertebrae were isolated on outcrop but could be identified to genus and growth stage.

The catalytic activity and selectivity of nanosize colloidal platinum (Pt) nanocrystals may depend strongly on their sizes and shapes. To determine the shape dependent catalytic behavior of Pt nanocrystals, two key steps are involved. First, shape controlled Pt nanocrystals must be synthesized at a high yield. Secondly, the passivation layer on the nanocrystal must be removed in order to measure the catalytic selectivity and activity while the particle shape is preserved. The former had been successfully demonstrated by us that platinum nanoparticles with a high percentage of cubic-, tetrahedral- and octahedral-like shapes, respectively, can be synthesized by a colloidal chemistry method [1,2]. The growth of the shape controlled Pt nanocrystal has been found to be the result of kinetic process [3]. To measure the shape dependent catalytic activity and selectivity of the Pt nanocrystals, the capping polymer must be removed. One method could be annealing the nanocrystals supported on a substrate for evaporating the capping polymer. Several questions, however, must be considered: (1) how high does the annealing temperature need to be to remove the capping polymer while the particle shape is still preserved? (2) to what temperature is the particle shape still stable? (3) is there a temperature induced shape transformation due to surface diffusion? (4) how high is the melting point of the Pt particles? and (5) what is the effect of substrate on nanoparticle melting? These questions have not only fundamental importance, but also practical impact on the catalysis applications of the particles because the chemical reaction may take place at a higher temperature.

Scanning Electron Microscopy (SEM) of thin film magnetic disk defects is challenging due to lubricant on the disk surface. The lubricant aids disk durability but interacts with the electron beam to form a contaminantation layer over the area of interest. A new cleaning technology allows the removal of the surface contamination while the specimen is in the SEM.

Plasma dry ashing of SEM samples to remove surface hydrocarbons is a well-known technique for specimen preparation. A number of commercial external plasma cleaning units are on the market for sample preparation outside the microscope. Zaluzec developed a technique for plasma cleaning the specimen and stage together prior to insertion into the analytical region of the electron microscope. But similar plasma cleaning within the SEM chamber must be avoided due to ion bombardment damage to the SEM and the deleterious effect of argon plasmas on ion pumps. XEI Scientific has developed a new device that creates neutral oxygen radicals from air. This technique oxidizes surface hydrocarbons into volatile gases that are easily carried away to the roughing and diffusion pumps.

We have developed a technique for measuring small strains during in-situ tensile tests in a Scanning Electron Microscope (SEM). The technique uses pattern recognition algorithms to locate markers on a gridded sample before and after deformation. The distortions in the grid are used to calculate the strains at each of the markers. The strains are then displayed in contour plots and correlated with the microstructure of the sample to help understand the local progression of strain as a function of applied load and microstructure.

Tensile experiments were performed on gridded notched and unnotched samples of a Ti-48Al-2Cr- 2Nb alloy (at%) in a Philips XL-30 FEGSEM using a 10,000 N Kamrath-Weiss in-situ straining stage. Gold was evaporated onto the samples through nickel grids with a mesh size of 17 μm. Electron backscatter images of the samples taken during testing were analyzed using a set of, interactive routines written in the Interactive Data Language (IDL).

A detailed understanding of phase transformation mechanisms in small particles is critical for the design of small metal particle catalysts and nanophase materials. For palladium supported on silica, it is known that under certain conditions, reduction of PdO can lead to the formation of small Pd metal particles containing central faceted voids[l]. In-situ microscopy studies show that the voids form when PdO is reduced at temperatures between 200 and 400°C but collapse when the temperature reaches about 550°C [2]. Here we present in-situ high resolution microscopy showing the details of the void formation process.

Model Pd/SiO2, catalysts were prepared by dispersing Pd metal over silica microspheres using techniques described elsewheretl]. The Pd/SiO2, catalyst were fully oxidize°C for 2 hours. The catalyst was crushed and dispersed over Mo grids and plasma cleaned to remove any residual carbonaceous material. A Philips CM 200 with a slow scan CCD camera and video recording system was used to recording HREM images during in situ reduction at 200°C.

The abilities of researchers to obtain high-quality images and other data from pin-mounted museum insect specimens using conventional scanning electron microscopy (SEM) are hindered by several necessary constraints. The specimens may represent unique exemplars (e.g., holotypes) upon which the taxon name rests. In some cases the specimen may no longer be extant in any environment outside the museum. Thus these insects must always be handled with extreme care,Tegardless of how they are to be observed.

Normal preparation of an insect for SEM involves sputter coating it with a conductive metal to minimize the effects of charging, and conductive paint must be applied to an obscure or uninteresting area to complete the connection to the specimen mount and thus to ground. Generally, unless such specimens have been newly collected, they will have already been killed and allowed to air dry, with a mounting pin inserted through the thorax. The body of the insect shrinks against the pin, which cannot then be removed for observation and later reinserted without damage.

In recent years the assembly of nanometer sized building blocks into two- and three-dimentional structures and functional materials has been an extremely active area of scientific research. A new class of materials, the DNA/nanoparticle hybrid materials and assemblies, which might have useful electrical, optical and structural properties, have been developed at Northwestern University. While characterizing particle morphology (size and shape) by subjecting it to the high vacuum environment in an electron microscope, the structure may have changed drastically from its natural state. The study of morphology of these DNA/Au nanoparticles in the liquid state was thus undertaken to further our understanding of the dynamics of the nanoparticles in a specific environment. This paper presents an in-situ observation of DNA/Au nanoparticle assembles in liquid media using environmental TEM.

Experiments were carried out with citrate-stabilized colloidal Au particles averaging 8 and 31 nm in diameter. Colloidal Au nanoparticles were obtained from a commercial source. 8 nm particles were modified with propylthiol-capped oligonucleotide, 3’HS(CH2)3-O(O)P(O)O-ATG-CTC-AAC-TCT, 1,whereas the 31 nm particles were modified with hexlylthiol-capped oligonucleotide, 3’TAG-GAC-TTA-CGC-O(O)P(O )O-(CH2)6SH, 2.

Decreasing dimensions and the necessity to understand the structure and composition of materials or devices on a nanometer scale has led to new developments in TEM. Previously EDX analysis had been established as the only analytical technique. In recent years the analytical capabilities of TEM have been augmented with a number of analytical techniques - such as electron energy-loss spectroscopy (EELS), electron holography, Lorentz microscopy, high-angle annular dark-field (HAADF). These have been developed or extended to yet unavailable levels of resolution. The Schottky field-emitters provide stable, reliable, coherent and high-current electron sources that are needed to get the best out of the mentioned analytical techniques.

The development of these analytical capabilities has been a parallel process in many different places and mainly led to dedicated microscopes optimized for one purpose only. This made it almost impossible to get different sets of analytical information from one specimen area simultaneously, and often the data even had to be collected from different specimens.

A new omega filter has successfully been installed in 200kV TEMs(see FIG. 1). Energy filtering TEM (EFTEM) is extremely useful to enhance contrast of biological specimens, to observe defects in thick semiconductor tips, to obtain a good compositional map in grain boundaries, to give structure image in the thick specimen regions and to obtain quantitative data by removing plasmon loss signals. In-column filters such as omega filter has advantages over postcolumn filters from points of cancellation of aberrations, to obtain iso-chromatic images and a freedom of selecting variety of magnifications.

Here, we discuss conditions of designing an omega filter. In usually, curved axis systems, which are common to energy analysis equipment, has large second order aberrations. Those aberrations are compensated in analyzers with single sector magnet with multi stage sextupole correctors. However, the adjustment of those correctors is difficult and residual aberrations destroy quality of the filtered image.

We have recently replaced the electron energy filter of the Zeiss EM 902 with an improved PMP filter. The design, incorporating concave curved entrance and exit faces and convex curves on the side facing the electrostatic mirror was based on the theoretical calculations of Jiang and Ottensmeyer and Barfels et al. Care was taken in the design of the filter to allow its introduction into the existing geometry of the microscope and its use of the existing electronics. As a result, dismantling the existing prism housing and support (which were used as the base for the new prism), reinstallation, and adjustment required only three working days. The resolution in tjie energy dispersive plane of the new filter was measured using the 15.0 eV plasmon peak of aluminum as an internal standard. Such measurements yielded a FWHM of 1.1 eV over the full image plane (fig. 1) with an optimum resolution of approximately 0.8 eV possible with corrections to the stability of the voltage supply and further small alignment adjustments.

This improved energy resolution permits the detection and imaging of signals in the low loss region previously inaccessible to us in the EM902.

We have developed a system (1) for automatically acquiring large numbers of high quality transmission electron micrographs under low dose conditions. This system has been implemented on a Philips CM200 Transmission Electron Microscope equipped with a Gatan MSC CCD camera. Implementing the automated data acquisition system requires that target locations be identified in a low magnification image and then accurately located at the center of the viewing area. The magnification is subsequently increased, the image is focused on an area adjacent to the target area and the final image is acquired. Centering an identified target location for subsequent high magnification imaging typically requires moving the specimen by many thousands of nm and accurately locating the target to within a few hundred nm. This movement is too large to be achieved using the image shift coils, which would be very accurate, and instead must be achieved using the goniometer.

We have measured the accuracy of the goniometer on the Philips CM200 and the results are shown in fig 1. Data were obtained by selecting a target area from a low magnification image [660x], moving to this target and then measuring the accuracy of the requested movement by cross correlation.

Since it's introduction into TEM in 1986 [1] SSCs have become an effective and easy-to-use solution for acquiring high quality digital images electronically. Their main advantages are excellent linearity, very high dynamic, high sensitivity, and low noise. These advantages have made SSCs a nondispensable tool for quantitative image analysis. Moreover, since SSCs make high quality TEM images available in a computer within fraction of seconds, on-line image processing and software driven automated TEM tuning has become possible [2]. Many of the experiments which are performed nowadays in the area of high resolution, low dose, holographic reconstruction, and EFTEM [3] would not be possible without the digital input coming from SSCs.

Like recording images with a film sheet camera, digital recording of images with SSC requires control of the TEM beam blanker (shutter) by the SSC synchronised with the image acquisition process.

This blanker (shutter) control is a critical link in the chain to the digital image. Many older TEMs do not have direct access to beam blanking coils, or contrary to modern TEMs their coils are not designed to support hysteresis-free fast beam blanking, what is essential for acquisition of high quality digital images by a SSC.

Recent advances with the cone-beam approach to tomography at the Advanced Microscopy and Imaging Laboratory (AMIL) have opened the possibility of employing tomography with the Shadow Projection X-Ray Microscope routinely when the specimen properties require it. The AMIL approach has been tested on small objects, without magnification, using conventional dental x-ray sources and a modestly diverging beam angle. The shadow projection Microscope, by contrast has a tenfold greater divergence and magnifies the specimen from unity to three or more orders of magnitude in resolution beyond the previous tests. The reader is reminded of the simplicity of the xray projection method and of the clarity of its images in fig. 1 and 2. The microscope can be operated in any laboratory and readily transported to alternate locations. Now that the AMIL data base and algorithms for tomography can be handled by a Pentium II processor the data gathering and reconstructions can also be managed at any laboratory installation.

Micro X-ray fluorescence (micro-XRF) is a useful nondestructive technique for multielement analysis of samples from a few hundred to a few micrometers in size. Micro-XRF is usually performed at synchrotron sources where element sensitivities are not compromised by micrometer spatial collimation of high flux beams. Ideally, micro-XRF would not have the burden of transporting samples to a synchrotron facility, but could be performed on a laboratory or portable scale. At the National Institute of Standards and Technology we are developing a micro-XRF system that combines a polycapillary optic with a standalone X-ray tube. This optic not only transmits the X-ray beam over 80 mm, but also focuses the beam to an area smaller than the unfocused beam size. The fine resolution combined with a high intensity produces a tool for laboratory scale micro-XRF analyses.

The X-ray focusing optic is a tapered, glass polycapillary optic. This optic, contained in an approximately 5 × 70 mm steel cylinder, transmits and focuses incoming X-rays to a spot 9.5 mm from the optic exit.

In photoelectron microscopy (PEM; also known as PEEM) ultraviolet light is used to liberate electrons from the surface of a specimen through the photoelectric effect. The emitted electrons (photoelectrons) have low kinetic energies (∼1 eV) and are accelerated by an electric field between the specimen and an anode, before being imaged by a lens system. The lens system forms the image of the specimen in parallel mode, as in TEM, rather than in scanning mode, as in SEM. Image contrast arises from differences in work function and from electric or magnetic fields over the specimen surface. Micro-fields associated with surface topography are also a source of contrast. Because of the low emission energies of the electrons PEM is a highly surface-specific technique and also is relatively non-destructive.

Several versions of the photoelectron microscope have been designed and constructed jointly by the University of Oregon (U0) and Portland State University (PSU), and the instrument has evolved to an advanced state of development.

The optimal method for evaluating fluorescence microscope has not been proposed. In this study we developed two quantitative methods using biological and non-biological materials as standard specimens. Based on these methods, a new water immersion lens was tested and its high sensitivity to fluorescence was demonstrated.

First, particles of a fluorescent glass (Luminass-1; Sumita Optical Glass) were used for the standard specimen. Particles with a few micrometer diameter were embedded in silicon oil on a quartz slide glass covered with a quartz glass slip and then observed. Under the fluorescence microscope, the spectra of emission light from the excited area with or without the particle were measured by a monochromator and a photomultiplier tube (PMT). The signal-to-background ratio (S/B) was calculated from these spectra (Fig. 1, Table 1). This specimen showed a significant advantage due to less photobleaching that permits a stable and long observation time.

The analysis of Auger and other excited electrons in the energy range from about 50eV to 2500eV provides a nearly non-destructive means to determine the surface composition of materials. It is both highly surface sensitive (a few atomic monolayers) and capable of high spatial resolution. This makes it an attractive alternative to energy dispersive x-ray analysis for the examination of ever smaller structures such as in semiconductor devices. For many applications however one important drawback has been the relatively long time required to make useful measurements - usually many seconds or minutes. Spectrum-imaging, in which an entire spectrum is acquired for each pixel in a digital scanned image, is one example for which Auger, spectroscopy becomes a prohibitively lengthy process. Similarly, the study of electron beam sensitive materials is difficult because the measurement time is often longer than the damage time. One method of reducing the measurement time is by acquiring the whole energy spectrum of interest in parallel. This is achieved with the Hyperbolic Field Analyser. (In electron energy loss spectroscopy this approach has lead to the highly successful Gatan energy filter.)