Scanning Electron MicroscopeOlin Rice's Keck Lab houses a Scanning Electron Microscope (SEM) that is invaluable the Macalester physics experience.  Instead of using light, the SEM employs an electron beam to scan sample surfaces.  This is made possible by an electric potential of 20,000 volts  within them microscope.  Electrons are accelerated through this potential in order to collide with the sample of the sample surface.  From the impact of ionization on the surface, due to the electron beam, x-rays are emitted from the sample and detected by a Si(Li) Dector.  The result is a high resultion and seemly 3D image of a sample element's surface.  The SEM is namely used for research in the physical sciences.