Transmission electron microscopes form images using an electron beam in a manner analogous to the way optical microscopes form images using visible light: lenses focus and magnify the beam of light (or electrons) after it has been transmitted through a thin specimen and eventually project a final image onto some sort of imaging device. Most modern electron microscopes operate over the magnification range from as low as 100x up to several 100,000x, often with the best images recorded over the range of 5000 to 100,000x due to limitations of the electon microscope and/or its operating environment. This type of operation is sometimes referred to as conventional TEM (cTEM) to distinguish it from imaging modes that put more stringent requirements on the instrument itself or its environment, or that require additional hardware. In this most simple mode of operation (pioneered in the 1930's by the likes of Ernst Ruska), the TEM uses a series of magenetic coil "electron lenses" to...
