Coal is remnants of plant matter that were compressed and held at a high temperature for eons. However, if plants are charred first, they become hard and brittle, and may resist compression. Under appropriate circumstances, anatomic detail can be elegantly retained. Ian Glasspool, Dianne Edwards, and Lindsey Axe have performed detailed studies on plant fossils recovered in England, near the Welsh border, that can be considered to be evidence for the earliest wildfire yet described on our planet. They examined a series of mesofossils, about one millimeter in size, which required microscopic study.

It is well known that chemical and structural changes occur to organic tissues during charring. This can mean that charcoal is resistant to decay and compression and it is also more reflective than non-charred material. Glasspool et al. used incident light and scanning electron microscopy to reveal 3-dimensional cellular detail of the specimens. Additional specimens were embedded and polished for reflectance microscopy. The results indicated that the specimens were charcoal.

Historically near-infrared (NIR) spectroscopy has enjoyed significant success as the industrial ‘cousin’ of the mid-infrared FTIR spectrometer. Most NIR spectrometers are significantly more rugged than their MIR counterparts, and are therefore suited for use as a QA/QC tool. Sample preparation is trivial or non-existent for most solid-state or liquid samples and data collection is rapid, while still achieving excellent signal to noise. All these factors combine to produce an analytical measurement technology with widespread applicability. Until relatively recently, its capabilities as a microspectroscopy and chemical imaging tool has been largely underutilized. Most NIR spectra have been collected from bulk, not microspectroscopic samples.

Mid-infrared (MIR) microscopy, based on a Fourier Transform infrared (FTIR) spectrometer, has been the infrared microspectroscopy technique most readily available up to now. It is a broadly employed chemical identification tool that is used to complement traditional light microscopy.

The newest generation of computer-controlled electron microscopes incorporates the ability to perform adjustments to microscopy conditions by comparing pairs of images and altering the conditions accordingly. Automation of electron microscope adjustments offers the advantages of accuracy, precision, efficiency, the ability to incorporate the adjustments into other automated procedures, and, for radiation-sensitive specimens, minimal exposure to the beam.

At present, automated functions include determination of eucentric height, focus, astigmatism, orientation and location of the stage tilt axis, centering of an image feature, and rotation center alignment. It is possible to automate other functions, so this list may be incomplete. In general, these functions are accomplished by induced image shifts, and, in many cases, the automated functions are completely analogous to the corresponding manual ones.

The exit electron wave from transmission electron microscopy (TEM) specimens contains both amplitude and phase information. In routine TEM imaging, only amplitude information is recorded on the recording devices (film or CCD camera) and phase information of the electron wave function normally is canceled out.

In 1947, Dennis Gabor proposed off-axis electron holography, a method of interference imaging in which the phase and amplitude components of the electron beam are obtained to correct spherical aberration of the transmission electron microscope to improve spatial resolution. In that process, the electron beam is split into the two beams: the un-scattered electron beam (i.e. the reference wave) and the image beam (or object wave) diffracted by the specimen and exiting the bottom of the specimen surface.

In characterization or failure analysis of new materials and semiconductor devices, the requirements for three dimensional observation and analysis are rapidly increasing. We discuss techniques for specimen preparation, three-dimensional observation, and elemental analysis of semiconductor devices that we developed using a system consisting of a dedicated focused ion beam (FIB) instrument and a scanning transmission electron microscope (STEM). The system utilizes a FIB-STEM compatible specimen holder with a specially designed rotation mechanism, which allows 360° rotation of a specimen on a conical stage (needle stub) around the ion beam axis of the FIB system and 360° rotation perpendicular to the electron beam in the STEM. A piece of sample (micro sample) is extracted from a specific-site by the micro-sampling technique and mounted on the needle stub. Instruments used in the study are the Hitachi FB-2100 FIB system with a micro-sampling attachment and the HD-2300 field emission 200kV STEM.

The ability to print what is seen on a computer screen so that it matches a printer (color matching) confounds even the most experienced. That's because computer monitors, even from the same manufacturer, cannot be made to display colors identically. Also, printers from different manufacturers contain several “libraries” of replacement colors in order to replace pixel values in an image from light (red, green and blue: RGB) to the primary colors for pigments (cyan, magenta, yellow and black: CMYK). Cameras use the primary colors for light and that is the way the digital image is stored and displayed; printers use the primary colors for pigments in ink. Thus, a printer must have a pixel by pixel list of replacement CMYK values for every RGB value in any image for that manufacturer's idea of faithful color matching.

Electron tomography using transmission electron microscopy (TEM) and related techniques (e.g., scanning transmission electron microscopy (STEM) or energy filtered TEM (EFTEM)) allow for 3-D microstructural and elemental mapping of specimens, and has been used successfully in the biological sciences where mass-thickness contrast dominates these mostly amorphous materials. Z-contrast STEM imaging via high angle annular dark field (HAADF) tomography has also been used successfully in the physical sciences. STEM, EFTEM, and holography tomography are more useful techniques for crystalline materials, since diffraction contrast in conventional TEM images can hinder image reconstruction. Typical tomography routines utilize conventional electron transparent foils, whereby the dimensions of the specimen perpendicular to the electron beam may be orders of magnitude greater than the specimen thickness parallel to the electron beam. Using this conventional specimen geometry, the effective specimen thickness increases as the specimen is tilted through the ± 70 degrees necessary for the tomographic acquisition process.

A silicon multi-cathode detector (SMCD) has been developed for microanalysis and x-ray mapping applications. The SMCD has a large active area (∼0.5 cm2), excellent energy resolution, and high count rate capability. The detector utilizes novel structures that have produced very low dark current, high electric field, uniform charge collection, low noise and high sensitivity to low energy x-rays. The detector's spectral response was evaluated using a 55Fe radioisotope source, as well as by fluorescing materials with an x-ray generator. Figure 1 shows a 55Fe spectrum with an energy resolution of 125 eV FWHM at 5.9 keV collected at 12 μs peaking time. This energy resolution has been repeatably measured on many different detectors. To evaluate the high count rate x-ray performance, which is very important for fast x-ray mapping, a Cu sample was fluoresced using a Rh-anode x-ray tube.

A major challenge in optical microscopy is to develop techniques with high spatial resolution, sensitivity, and chemical specificity. The latter, chemical specificity, is typically achieved through some form of labeling, which has potential to alter the nature of the sample under investigation. Raman or infrared (IR) microscopy can be utilized to image samples in their natural form using molecular vibrations as a contrast mechanism. IR microscopy suffers from spatial resolution issues, and spontaneous Raman microscopy suffers from low scattering cross-sections, so that high laser power is often required, introducing the possibility of sample photo-damage. Scattering cross-sections for Coherent Anti-Stokes Raman Scattering (CARS) are typically several orders of magnitude greater than those of spontaneous Raman Scattering. This, in addition to the high spatial resolution inherent in nonlinear optical microscopy, has led CARS microscopy to begin emerging as a powerful, noninvasive technique for biological and material imaging.

Insect tissue is often difficult to prepare for electron microscopy because of the impenetrable barrier surrounding the body tissues. Drosophila salivary glands have been used for numerous studies because of the large size of the cells and their large polytene chromosomes. Early TEM studies of salivary glands used a protocol that took several days. We were able to achieve excellent preservation and good ultrastructure in Drosophila salivary glands and imaginal discs from Stage L3 larvae using microwave processing in a protocol requiring less than 2 hours.

We used a Pelco Laboratory microwave (model #3451) equipped with a Cold Spot, Steadytemp chiller/recirculator run at 15° C, and vacuum chamber (Ted Pella, Mountain Lakes, CA). The heads and attached salivary glands were removed from the animals and placed in PBS. The tissue was transferred to Pelco prep-eze specimen holders (#36157) for ease of handling. Our goal was to use the microwave effect, not the heating effect, to prepare the tissue.

Electron backscatter diffraction is a powerful technique that has gained momentum in materials science research over the last ten years. Recent advances in electron microscope technology and automation has made EBSD a more viable and routine analytical tool.

Sample preparation is a key component in the use of EBSD due to the nature of the backscattered signal. Pattern formation is from the top 10-50 nm of the sample surface, and therefore, mechanical damage remaining from sample preparation will result in a poor quality signal. Several methods of sample preparation have been investigated that vary in abrasive material used, preparation time, and material system. Some approaches have used a combinatorial approach of silicon carbide papers, aluminum oxide papers, and aluminum oxide suspension with a polishing cloth to prepare tantalum.

The Microscopy Society of America (MSA) is a vigorous professional society of close to 3000 members, founded more than a half century ago. The membership is an unusual mix of scientists, engineers, and technologists in diverse fields of biological, materials, medical, and physical science and technology.

Education is a primary function of a scientific society. Microscopists exchange professional information at meetings and in technical publications, but MSA is also very conscious of the importance of improving the scientific awareness of the general public. MSA has chosen to do so with an educational outreach program at the middle school level, called Project Micro (Microscopy In Curriculum - Research Outreach). Our goal is to place MSA-member volunteers in the classroom, to help teachers use microscopes to introduce scientific inquiry.