Not Your Usual Dell XPS
Analysis doesn’t begin or end with the TEM. I was shown two additional machines capable of equally powerful but very different types of materials analysis. Both were housed in a room that somehow reminded me very much of my high school science lab. Perhaps it was the periodic table poster on the wall, speckled linoleum tiling, and aesthetic love affair with gray and beige. In any case, the two machines before me looked like no instruments I’d ever seen before, a seemingly haphazard hodgepodge of gleaming columns, rivets, and tubing.
The first machine was a tool for ESCA (Electron Spectroscopy for Chemical Analysis; also known as X-ray Photoelectron Spectroscopy, or XPS). ESCA is used to determine surface atomic composition and chemical bonding. When a sample gets bombarded with aluminum K-alpha X-rays, it will emit electrons characteristic of the chemical elements present within a few nanometers of the surface.
“The electrons are separated by energy through the hemispheric analyzer,” explained the resident tech. “By analyzing the energy of those electrons, we can identify the element from which that electron came. By looking even closer at the energy of the electron, we can evaluate the chemical bonding states of that atom’s electron from the element it came from.”