postheadericon Smart Utility of the Electron Gun in Different Works

The electron gun is one of the essential components of a cathode ray tube or instruments such as electron microscopes. These devices involve an electron beam and the electron gun forms the electron source of this beam.

General principle

In the case of a scanning electron microscope, the electron gun is the source of the electron beam that will scan the surface of the sample. The quality of the images and the analytical precision that can be achieved with a SEM require that the electronic spot on the sample be at once fine, intense and stable. High intensity in a smallest possible spot requires a “bright” source. The intensity will be stable only if the emission of the source is also stable.

The principle of the electron gun is to extract the electrons from a conductive material (which is an almost inexhaustible reserve) to the vacuum where they are accelerated by an electric field. The electron beam thus obtained is processed by the electronic column which makes it a fine probe scanned on the sample.

There are 2 families of electron gun according to the principle used to extract the electrons.

  • The thermionic emission, with the filaments of tungsten and spikes LaB 6
  • The field electron emission

According to these distinctions and the mode of operation, the electron guns have different properties and characteristics. There are physical quantities to characterize them. The main one is the brilliance but the service life is also particularly important, but also the stability. The maximum available current can also be taken into consideration, but also the energy dispersion

An electron gun really exists. But it is not a weapon of war but a peaceful part that you probably own or have at least had. An electron gun is part of a picture tube. It is that part that ensures a constant flow of electrons, which collide with the inside of the screen and there provide a light point. That light point moves so quickly in a certain pattern across the screen, that we get the impression that there is a complete picture there. The electrons themselves come from a metal part that we call the cathode, and which is heated in one way or another.




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