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Electron gun from an oscilloscope CRT Setup of an electron gun. 1. Hot cathode.2. Wehnelt cylinder.3. Anode. A direct current, electrostatic thermionic electron gun is formed from several parts: a hot cathode, which is heated to create a stream of electrons via thermionic emission; electrodes generating an electric field to focus the electron beam (such as a Wehnelt cylinder); and one or more ...
A cross-section view, showing how a Wehnelt localizes emissions at the filament tip and serves as a convergent electrostatic lens. A Wehnelt cylinder (also known as Wehnelt cap, grid cap or simply Wehnelt) is an electrode in the electron gun assembly of some thermionic devices, used for focusing and control of the electron beam.
Schottky-emitter electron source of an Electron microscope. A field emission gun (FEG) is a type of electron gun in which a sharply pointed Müller-type [clarification needed] emitter [1]: 87–128 is held at several kilovolts negative potential relative to a nearby electrode, so that there is sufficient potential gradient at the emitter surface to cause field electron emission.
The basic components of a typical electron-beam processing device include: [1] an electron gun (consisting of a cathode, grid, and anode), used to generate and accelerate the primary beam; and, a magnetic optical (focusing and deflection) system, used for controlling the way in which the electron beam impinges on the material being processed ...
The key component of a photoinjector is a photocathode, which is located inside the cavity of electron gun (usually, a 0.6-fractional cell for optimal distribution of accelerating field). Extracted electron beam suffers from its own space-charge fields that deteriorate the beam brightness. For that reason, photoelectron guns often have one or ...
A parts book, parts catalogue or illustrated part catalogue is a book published by a manufacturer which contains the illustrations, part numbers and other relevant data for their products or parts thereof. Parts books were often issued as microfiche, though this has fallen out of favour. Now, many manufacturers offer this information digitally ...
The following other wikis use this file: Usage on ca.wikipedia.org Canó d'electrons; Usage on en.wikiversity.org Quizbank/Electricity and Magnetism (calculus based)/QBCh7
Electron capture ionization (ECI) is the ionization of a gas phase atom or molecule by attachment of an electron to create an ion of the form A −•.The reaction is + where the M over the arrow denotes that to conserve energy and momentum a third body is required (the molecularity of the reaction is three).