Traditionally, focused ion beam (FIB) microscopy systems have been used as instruments to repair integrated circuits, isolate defects or prepare mateiials for characterization with other techniques. Recently however, FIB microscopy has been used extensively as a standalone characterization technique. Typically, FIB microscopy can be used to probe site specific areas of a sample through secondary electron and ion imaging, energy dispersive x-ray analysis (EDX), or secondary ion mass spectroscopy (SIMS). These analyses will often combine two-dimensional elemental mapping or sputter depth profiles with imaging to investigate spatial variations of chemical and imaging signals. Inherently, these investigations are confined to two dimensions but often, complex materials problems are more easily understood if chemical and geometric information can be collected.

Projects that require viewing dozens or hundreds of specimens often include countless hours for specimen preparation. Specimens are often affixed to metal or carbon stubs with conductive tape, paint or paste (Rampley, 1976; Witcomb, 1981). The use of conductive paint or paste requires substantial mounting and drying times prior to coating with conductive metal or carbon and observation in a scanning electron microscope (SEM). We here describe a simpler protocol for mounting specimens to expedite specimen preparation.

During a recent study, where cryofractured salmon egg membranes were mounted on edge to view transverse sections, we needed an expedient method of specimen mounting to quickly view hundreds of samples. We experimented with mounting specimens in metal putty, a product used by fishermen for weighting fishing line. The methodology described here solved some of the problems of messy specimen mounting and eliminated the need to wait for curing before coating and observation.

Stephen Carmichael wrote about Cryoelectron Tomography in the May 2003 issue of Microscopy Today. Citing new preparation methods, small cells can be vitrified, observed frozen in the TEM and a series of digital images captured while the specimen is being rotated around the axis perpendicular to the electron beam producing a 3-D tomogram. Gina Sosinski and Maryann Martone wrote about imaging big and messy biological structures using cryo-electron Tomography in the July issue of Microscopy Today. Cryo-HRSEM now also seeks to provide 3-D information approaching the molecular level from frozen hydrated cell and molecular systems. Vitrification procedures for small specimens such as platelets and biomolecules on grids are accomplished by plunge freezing in liquefied etiiane as is done with cryo-TEM procedures. Bulk specimens such as organic hydrogels and tissues are routinely high pressure frozen (HPF) in 3mm gold planchets. Employing an in-lens cryostage, identical to those used in cryo-TEM, cryo-HRSEM provides 3-D high-resolution images because secondary electrons are efficiently collected above the lens in a single scan thus minimizing specimen irradiation.

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.

Propylene oxide (1,2-epoxy propane) has long been utilized as a transitional solvent in the preparation of biological tissues. This compound compound is completely miscible with the various epoxy resins utilized for infiltrating tissues. Ethanol, perhaps the most widely used dehydration agent, does not possess this characteristic and must be removed before the process of infiltration commences. It is common practice amongst biological microscopists to pass tissues for a few minutes through pure propylene oxide (PO) immediately prior to infiltration. The tissues then are pre-infiltrated with various proportions of PO and the embedding medium of choice. For example, one traditional recipe takes the tissues progressively from pure PO to 2:1 PO/resin, 1:1 PO/resin, and 1:2 PO/resin mixtures, with stays of a few minutes at eacil stage. A lengthy procedure such as tills probably is not necessary and has never been favored by this worker.

Very small samples (under 1 mm) prepared for SEM viewing can be sprinkled randomly on an adhesive-coated stub, or manipulated into position with various tools (fine forceps, pointed stick, cotton applicator, hair brush) under a magnifier or stereo microscope. None of these methods allows reliable, damage-free control over the orientation of the sample. Here follow plans for a simple, portable “Vacuum forceps” to create a mild vacuum th rough a micro-fme tip to hold and orient SEM samples as they are applied to the adhesive. It is also useful for sorting samples. Commercial vacuum forceps with on-board vacuum range in price from $500 to $900. This unit was built from new parts for under $100.

The vacuum pump is from a portable motorized pipetter, such as the Drurnmond Scientific Portable Pipet Aid, or Mano stat Mopet (Figure 1). We have used the Drummond 9V motor and pump assembly.

Biowarfare was first documented in the eighteenth century during the French and Indian War when the British distributed smallpox-contaminated blankets to the American Indians. Smallpox is considered a likely agent even today because the USSR was known to have produced and stockpiled large amounts of the virus even after signing the 1972 treaty prohibiting such production. Because of the large number of workers involved and the poor economy, the security of these stockpiles is unclear [1, txtwriler.com/Backgrounders/Bioterrorism/bioterrar4.html]. Since the terrorist attacks in the United States in 2001, world attention has been drawn to terrorism and potential release of dangerous biological organisms. Considerable efforts are being made to establish methods for rapidly recognizing these agents. Numerous electron microscopy (EM) laboratories have been approached to join rapid response teams for the detection of viral agents. However, several issues should be carefully considered before an EM laboratory agrees to participate in surveillance.

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.

Low accelerating voltage operation is an excellent mode of scanning electron microscopy and it is extensively used for measurements in semiconductor production. The beam penetration is small, and if properly applied, the specimen charging is kept at acceptable levels. But, is this always enough? Today, the scanning electron microscope (SEM) is being used in photomask metrology and imaging where charging is excessive. Charging is difficult to quantify and control as it varies greatly with instruments, operating conditions and sample. Therefore, it is also very difficult to model accurately. For accurate metrology charging must be overcome because the dynamic charging of the sample deflects the electron beam from its intended position and the intensity of the induced signal may vary uncontrollably. Deflection of the electron beam of even a few nanometers potentially results in a measurement error that is significant to modern semiconductor production.