What scientific instrument uses backscattered and secondary electrons?

masholly

The Scanning Electron Microscope consists of an energetically well defined, highly focused beam of electrons scanned across a sample. Secondary Electron Imaging (SEI) works on the principle that this electron beam generates a 'splash' of electrons with kinetic energies much lower than the primary incident electrons, called secondary electrons. Because of their low energies and low penetration depth, the detection of secondary electrons as a function of primary beam position makes it possible to attain high magnifications (as much as x100,000 in some cases) and high resolutions (up to %7E40A resolution) for imaging the areas of interest. Backscattered Electron Imaging (BEI) detects high energy electrons which backscatter quasi-elastically off the sample. This imaging detector operates in two modes: topographical, which yields a topographic image of the sample {surface;} and compositional, which distinguishes between areas of relative low and high average atomic weights. This technique is extremely useful for locating areas with concentrations of heavy elements not necessarily visible to the naked eye or to the secondary electron detector. http://www.physics.montana.edu/ICAL/pages/sem.htm [Link added March 20, 2008 -- Zbeckabee] Jul 11 00, 12:14 PM

griffinj

The scanning electron microscope Mar 10 04, 4:29 PM