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.