... but by using electrons as opposed to light. A stream of electrons is created by a heated filament acting as a cathode, this stream is then accelerated toward the specimen using a positive electrical potential, the anode, the specimen lies between the anode and the cathode. The electrons can be focused into a beam between metal apertures, using magnetic lenses, as electrons carry a negative charge, glass lenses are not used as the electrons cannot pass through glass. The electron beam must pass through a vacuum as molecules in air would scatter the electrons. This beam is then focused onto the sample, which is mounted on copper grids for support. Interactions with the sample create an image, where they are absorbed or scattered a dark electron dense image is created and where they are allowed to pass through a light electron dense image is created. Unlike light lenses, you cannot ...

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