in surface electrical potentials on a specimen, is now one of several imaging modes used for the characterization, diagnosis and failure analysis of semiconductors. As many as half of the SEMs sold are believed to be used in semiconductor applications. Everhart studied contrast mechanisms in detail and developed a new theory of reflection of electrons from solids. He also made some of the first quantitative studies of the effects of beam penetration on image formation in the SEM. In 1960 Everhart and Richard F. M. Thornley published a description for the improved design of a secondary electron detector, since known as the Everhart–Thornley detector. Everhart and Thornley increased the efficiency of existing detectors by adding a light pipe to carry the photon signal from the scintillator inside the evacuated specimen chamber of the scanning electron microscopes to the photomultiplier outside the chamber. This strengthened the signal collected and improved the signal-to-noise ratio. In 1963, Pease and Nixon incorporated the Everhart-Thornley detector into their prototype for the first commercial SEM, later developed as the Cambridge Scientific Instruments Mark I Stereoscan. This type of secondary electron and back-scattered electron detector is still used in modern scanning electron microscopes (SEMs). By using various types of detectors with SEM, it becomes possible to map the topography, crystallography and composition of specimens being examined. In the 1960s, Wells, Everhart, and Matta built an advanced SEM for semiconductor studies and microfabrication at Westinghouse Laboratories in Pittsburgh. They were able to combine signals so to more effectively examine multiple layers in active devices, an early example of EBIC imaging. University of California, Berkeley From 1958-1978 Everhart was a professor and latterly department chairman of engineering and computer science, at the University of California at Berkeley. There he supported the construction of the first scanning electron microscope in a U.S. university. Cornell University In January 1979, he became Joseph Silbert Dean of the College of Engineering at Cornell University, Ithaca, New York. University of Illinois Everhart served as chancellor of the University of Illinois at Urbana-Champaign from 1984 to 1987. As chancellor, Everhart was involved in proposals for and development of the Beckman Institute for Advanced Science and Technology, an interdisciplinary research institute substantially funded by an appeal to Arnold Orville Beckman. In a formal invitation to proposed members of the Administrative Committee for the Beckman Institute, Everhart wrote that creation of the Beckman Institute was "an exceptional