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American Journal of Physics

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Transmission electron microscopes, Electron microscopy


A simple transmission electron microscope (TEM) suitable for lecture demonstrations is described. In this TEM electrons are created in a glow discharge between two parallel electrodes in air at a reduced pressure. The electrons are collimated by a small hole in theanode, focused by a solenoid that acts as an electromagnetic lens, and imaged on a thin layer of phosphor deposited inside an Erlenmeyer flask. An image of a biological sample placed between the source and the lens can be magnified about 20 times. The microscope uses inexpensive components that can be quickly assembled during a demonstration. The TEMprovides a visual and memorable display that highlights phenomena such as mean-free-path, charged particle optics, electrical discharges, and cathodoluminescence.


Copyright 2006 American Association of Physics Teachers. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Association of Physics Teachers. The following article appeared in American Journal of Physics. November 2006, Vol. 74 Issue 11, p953-956 and may be found at:



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