Scanning electron microscope, 1965.
© Science Museum / Science & Society Picture Library
One of the first SEMs (scanning electron microscopes) produced by Cambridge Instruments and sold under the name 'Stereoscan'. The image is built up on a television screen, achieved by scanning a fine beam of electrons with a zig-zag motion, acros the surface of the specimen and collecting the electrons knocked out of the surface of the specimen by the electron beam. Microscopes using this principle were originally constructed by Manfred von Ardenne (b 1906) and Max Knoll (1897-1969), in 1933-1934.