For sample preparation, e.g. cross-sectioning and thinning, SEM and TEM microscopists routinely use mechanical techniques (e.g., cleaving, slicing, lapping, polishing, and microtoming) and chemical or broad beam ion thinning. Two problems they run into are (1) locating the site of and crosssectioning or thinning at the site of extremely small features at specific locations (site specific samples) and (2) dealing with materials and material systems that are altered or destroyed by mechanical sample preparation (material-specific samples). These material systems may contain multiple components with dramatically different characteristics, such as hardness or chemical reactivity.

Many of these limitations can be overcome by using focused ion beam (FIB) micromachining, often referred to as “FIB microsurgery.” This technique can locate micron and submicron features and use precisely placed cuts to cross section and thin samples.

During the past two decades, the scanning electron microscope (SEM) has become an indispensable tool for morphological observation in materials and biological sciences. With energy dispersive x-ray spectroscopy (EDS) and wavelength dispersive spectroscopy (WDS), rapid chemical characterization of microscopic features has also become commonplace. As developments in manufacturing methods allow fabrication of ever smaller devices and quality control has achieved higher priority, demand for microscopic characterization by SEM has continuously increased.

Many applications where SEM/EDS evaluation could be useful involve samples that are not electrically conductive. Nonconductive samples are subject to a buildup of electrons on the examined surface. This buildup of electrons, or “charging” eventually causes scattering of the incoming electron beam, which interferes with imaging and analysis. Nonconductive samples have traditionally required pretreatment, by coating with a conductive film, before SEM examination.

Wouldn't it be nice to have some kind of laboratory hood in which gravity is greatly reduced so we could grow more perfect crystals or do biological experiments without having to go into orbit. There was a report in Science last year which hinted that gravity cancellation or modification just might be possible some day, but I doubt that any of our readers noticed it. The title was “Inertia: Does Empty Space Put Up the Resistance?”. One has to read this news report carefully to find that physicists have long pondered the connection between the inertial property of mass and the gravitational attraction between masses and that the work quoted here, suggests that once inertia is understood it might be controlled, even canceled. Upon inquiry the editor, Robert Matthews found other physicists believed that the ability to modify inertia could soon be tested experimentally but remarked that “it is a bit too early to be talking about inertia free star ships.”

A number of important imaging applications, including neurobiology and precision motion analysis, require a digital camera that provides both high performance (low noise, extended linear gray scale) and high frame rates. In recent years, manufacturers have responded to this need with faster digitization/readout electronics - as high as several MHz (Mpixels/second). When combined with on-chip binning, this has enabled frame rates up to 30 frames/second from some high performance cameras. Unfortunately, even this is not fast enough for situations where two images must be acquired virtually simultaneously, or where a rapid dynamic event needs to be captured with a fast burst of images.

As laboratories like the Materials Analysis User Center (MAUC) in the High Temperature Materials Laboratory, at Oak Ridge National Laboratory move from analog to digital imaging systems, the process for acquiring, processing, analyzing, and publishing research results is changing. In this case since original scientific data exist only in digital form, analog systems for gathering, staring, and transmitting data are being set aside in favor of digital systems. In order to adequately protect original scientific data and to ensure that digital laboratories have the same (or greater) functionality as analog laboratories, scientists must focus on building information systems that make data highly available, highly reliable, and quickly accessible. Meeting these three objectives imposes special requirements for both data storage systems and data networks.

Lateral Force Microscopy (LFU) is a scanning probe microscopy (SPM) technique that identifies and maps relative differences in surface frictional characteristics. It is one of several techniques developed as extensions to the basic topographical mapping capabilities of SPM. LFM is particularly useful for differentiating among materials on surfaces. Applications include identifying transitions between different components in polymer blends, composites and other mixtures, identifying organic and other contaminants on surfaces, delineating coverage by coatings and other surface layers, and chemical force microscopy using functionalized tips.

In this series we have explained why x-ray spectrometers are useful in electron microscopes and, to some extent, how they work. In this article I will discuss some of the physics behind the detector.

First I have been asked to explain what a hole is. In a silicon crystal every silicon atom is bound to four others with covalent bonds. Every electron has a home, which consists of its home atom in the case of the inner electrons. The four outer (or valence) electrons have a home on the road, shuttling back and forth between too atoms each. In this way the five atoms share eight electrons among themselves.

A.C. magnetic field (ACMF) sources and their EM interaction mechanisms are discussed in this installment, which continues our July/August series on preventing and resolving site magnetic field problems. This article carries forward the theme of a primer on the basic physical causes and effects of A.C. magnetic fields.with special emphasis on the manner in which such fields may affect site EM instrumentation. Experience has demonstrated that a basic understanding of the various aspects of ACMF sources will often prove helpful in identifying the sources which actually pose a threat to EM site operations.

When physicists of the last century were studying the nature of light and its application to the newly-refined microscopes, they devised certain laws relating to physical limitations to resolution. These laws had something to do with the wavelength of light being proportional to the limit of resolution. Lately these laws haven't just been broken, they've been shattered! But in all fairness to our predecessors, light is being used now in a manner that they could not have imagined. The scanning interferometric apertureless microscope (SIAM) recently refined by a team led by H. Kumar Wickramasinghe with colleagues Frederic Zenhausern and Yves Martin is a prime example.

During the past two decades, the scanning electron microscope (SEM) has become an indispensable tool for morphological observation in materials and biological sciences. With energy dispersive x-ray spectroscopy (EDS) and wavelength dispersive spectroscopy (WDS), rapid chemical characterization of microscopic features has also become commonplace. As developments in manufacturing methods allow fabrication of ever smaller devices and quality control has achieved higher priority, demand for microscopic characterization by SEM has continuously increased.

A microscopist is presented with a special problem when asked to characterize a population of particles. In order to adequately describe the sample, it may be necessary to examine hundreds or even thousands of individual particles, recording the size, shape, identity or other parameters of interest. To manually characterize a statistically significant fraction of the sample could require many hours of tedious work at the scope, followed by still more tedious hours of data reduction. What is needed is a technique to automate the repetitive parts of this process; the recognition and characterization of particles in the sample and the reduction of data and presentation of results. This technique is automated particle analysis.