I am a professor at a university, and like most of my colleagues I divide my time between teaching, administration, service work and basic research. Of all these activities it is the research that I and my students have dene that has been most important for the advancement of our respective careers. Research is indeed the life blood of science and the meeting of MSA in New Orleans this month, will be an occasion to celebrate this and to show each other what we have been doing since we saw each other in Cincinnati last year.

I am driven to write this column because some nights ago I watched a program on the problems surrounding the delivery of the impending “universal” health care package. On the stage were Senators Dole and Mitchell, along with people representing different opinions about the issues at hand.

In recent years, microscopy systems have become more capable of capturing, transferring, and manipulating electronic images. In the last issue of this publication, there was a summary of different image format types and their flexibility for use with microscopy. This article will briefly discuss converting images among different formats, which often becomes necessary when transferring images from one software application to another or creating hardcopy of the image. In order to transfer the image, either the original software has to save the image to a format which the new software or output device can read, or that new software or device has to read a format which is native to the image generating software.

Sometimes (happy days), this all works out straightforwardly. Other times, transferring an image is impossible. The user then has the choice of writing his own conversion software, finding freeware, or purchasing a commercial conversion utility.

A combination of electron microscope and x-ray spectrometer is a very powerful tool. Not only can one see a sample in great detail, but one can determine, and even map, the chemical elements. In Part 1, I discussed some of the basics of energy dispersive x-ray spectroscopy (EDS or EDX). The heart of the spectrometer is a small piece of single crystal silicon about the size and shape of a shirt button, and about twice as thick. It has been selected for high purity, and then lithium drifted to compensate the remaining impurities.

The lithium is carefully drifted into the crystal button in order to exactly compensate the impurities in the crystal that would create leakage current. This is done at about 60° C under an electric field. It is then evaluated and re-drifted for a final clean up of any uncompensated impurity atoms that remain.

The basic trick is to produce a very smooth, featureless background, preferably using low Z (atomic number) or low density materials. The following three methods exploit in 1: round glass coverslips, in 2: double stick tape and/or colloidal graphite paint for backgrounds, and in 3: a combination low Z plus high Z conductive coating strategy is described which when used in combination with 2, also produces the desired background effect.

1. I've done the following for pollen grains, rust spores, and soil particles (dried down onto glass coverslip support surface from water or ethanol, they just stick naturally), should work with larger samples, eg., insects, seeds, provided that any paint you use to mount the sample to the glass coverslip does not spread out beyond the edges of the sample so you don't see it in the background.

In this day of resistance toward big science projects it may be futile to worry about how to produce the largest possible microscope. But since it doesn't cost anything to day dream, and times may change, it is fun to consider superlative enterprises.

One must grant that Ultra High Voltage Electron Microscopes are much larger than we wish they were, and one wonders if there is a contest afoot to see which AEM can have the largest foot print, but a new possibility has arisen which, seriously, could dwarf them all - yet have some possible use.

I am referring to the discovery of an example of a gravitation lens for ordinary light. Now the distinguishing characteristic of a microscope from a telescope is that the object eyepiece and the object near the focal length of the lens.

Many laboratories today wish to assure their clients of the implementation of a sound quality system. The International Standards Organization (ISO) has the 9000 series of quality systems which is recognized globally. This article specifically addresses issues to be considered for a good quality system in a modern service oriented microscopy laboratory.

The quality system is devised to attain certain objectives which are consistent throughout the company, whether they be research and development, marketing and sales, supply of a service, procurement, shipping, etc. Each company devises a quality system specific to their business and that serves their own and their client's needs. Some of these objectives may be the following: assurance of cost effective operations; prevention of errors in all aspects of the operation; assurance to the client that the objectives, deliverables and time frame are understood, prevention of delays; increase of productivity, a commitment to meeting the client's quality assurance requirements.

A variety of energy emissions occur as a result of primary beam interaction with the specimen surface. Secondary electrons, x-rays, visible photons, near IR photons, and Auger electrons are emitted during inelastic scattering of electrons. Backscattered electrons (BSE) are emitted during elastic scattering of primary electrons. Backscattered electrons are those electrons which pass through the electron cloud of an atom and change direction without much energy loss. BSEs may diffuse into the sample or may escape from the sample surface. In practice, the primary electron beam penetrates deeply into low Z (atomic number) materials and produces few BSEs while high Z materials retard primary beam penetration and emit large numbers of BSEs. According to Murata et al., the higher the atomic number, the smaller the mean free path between electron scattering events (i.e. 528 Å for Al vs. 50 Å for Au at 30 KeV) and the higher the probability of scattering.

It is very important to be able to deliver tiny droplets of liquid onto any surface. There are two general methods for this. One, a glass fiber brush seaied into a capillary; and, the other, a polyethylene micrapipette. Both are capable of delivering droplets as small as 100 μm in diameter. Description of the glass fiber brush follows. Part II, later in this publication, will describe the polyethylene micropipette.

We have borrowed this clever idea from Fred Schneider of IBM (private communication). A bundle of 20 to 30 glass fibers, 5 to 8 mm long and about 20 μm in diameter, is sealed with a microflame into one end of a glass capillary. A melting point capillary 1 to 2 mm in diameter and open at both ends is convenient (Fig. 1), To use for small drop deposition, the capillary is partly filled (2 to 3 cm. long column of the desired liquid} so that the sealed-in end of the glass fiber bundle is fully immersed.

Photographic film has played a central role in the recording of microscope images since the invention of photography in the 1830s. Photography rapidly creates an accurate record of the microscopic specimen and avoids the subjectivity that was inherent in written and artistic descriptions of visual observations. Both instant and conventional films offer high resolution, the ability to record a large tonal gradation, and a stable media for long-term data storage.

Newer techniques, such as thermal, ink jet, and laser prints, have grown in popularity because they offer ease-of-use or lower per-image cost. Despite recent improvements, none of these techniques offer the resolution or stability of a photograph. In general, people have been forced to sacrifice quality and permanence in order to achieve the lower per-image cost and ease-of-use promised by alternative recording systems.

If you were to examine surfaces in a typical SEM system using any number of surface analysis techniques, I think you'd be surprised at the results. You might expect to see all materials used to construct the vacuum chamber (e.g., plastic or stainless steel), but frequently the spectra will show mostly carbon, the most frequent culprit of SEM contamination. Carbon is adsorbed onto the walls of the vacuum chamber and builds up on the sample, thereby contaminating the SEM system and compromising image quality. By manufacturing and maintaining a clean SEM environment, this problem can be avoided, and you will increase the overall performance of your SEM system.

We are all familiar with digital imaging for SEM instruments. Digital Imaging for TEM applications is not as well established. Nevertheless, it seems clear that it will not be long before digital imaging for TEM becomes common place. Systems are improving and costs are plummeting. With this in mind it is timely to review what digital imaging for TEM involves.

In normal TEM operation an electron bream is scattered through a thin section of a sample. Physical mechanisms cause the electrons of the beam to scatter, producing bright-field images, dark-field images and diffraction patterns. The operator adjusts the instrument to display one of these images on the instrument's viewing screen. A photographic record is collected by flipping the viewing screen and exposing a sheet of film held in the TEM's camera. Exposed negatives can be removed for developing and printing in batches, using standard darkroom techniques.

One of Olympus' not well known product in the American market is the UH3 Scanning Acoustic Microscope (SAM). This state of the art, highly versatile microscope has many applications from non-destructive imaging to biomedical analysis, to pharmaceutical applications to name a few areas of current industrial interest.

The principle behind SAM is quite simple, and uses the basic physical laws of reflection. High frequency sound waves are mechanically produced by a piezoelectric crystal. A high voltage impulse spike starts the crystal vibrating at its preset resonant frequency emitting acoustical plane waves through a medium with a relatively high sound velocity such as sapphire. The waves are made to converge by a half-spherical lens at the bottom of the sapphire rod. The diameter of the lens is less than one millimeter and depends on the operating frequency. The lower the frequency, the larger is the diameter of the lens.

Historically, microscopes have been used to gather morphologic data. We have called people who use these instruments microscopists, and it is implied that microscopists are morphologists. As was pointed out in the April/May issue of this newsletter, useful information about a specimen is also gained from temporal analysis. Further, it has been appreciated that the new family of scanning probe microscopes can be used to gather additional types of information so that these instruments have the potential to be useful beyond the dreams of a conventional microscopist. As we will discuss in this article, the future is here for one such application.

The atomic force microscope (AFM) takes advantage of the leverage afforded by the deflection of a laser beam bounced off a cantilevered stylus that is scanned over the surface of a specimen.

If you do not have a Faraday-type incident beam current meter on your SEM, use the following procedure to set up a calibrated, reproducible beam current when doing EDS. Of course, you won't know the actual vaiue of the beam current in picoamps, but at least you'll know you can set the same value from sample to sample and day to day.

Mount a small, clean metal foil, 2x3 mm, aluminum or copper, onto the edge of each stub that the samples and standards are mounted on using colloidal graphite paint or double stick tape (after carbon or other evaporative conductive coatings have been applied to sample). Run a little colloidal graphite around an edge or two to provide additional adhesive support and a conductive bridge between the foil and the stub. Before taking sample or standards spectra, move the electron beam to the foil and as you accumulate its spectrum, set a region of interest, or window, on the principle K-shell peak of the aluminum or copper spectrum.