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Physics, Techniques and Procedures

Electron gun

a device that shoots out electrons as a beam in one direction. The electron gun is an essential part of the television camera and the television monitor and consists of a cathode with a heating coil and a control grid. Heating liberates electrons from the cathode by thermionic emission, and the electron cloud is formed into a beam by the control grid which also initiates the acceleration of the electron beam through the vacuum tube (towards the target of the television camera or the fluorescent screen of the television monitor). The term electron gun is also used for the source of the electron beam in cine CT scanners. Here, the electron beam is accelerated towards the anode rings to produce the X-ray beam.

HJS