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Secondary electron emission is used in photomultiplier tubes and image intensifier tubes to amplify the small number of photoelectrons produced by photoemission, making the tube more sensitive. It also occurs as an undesirable side effect in electronic vacuum tubes when electrons from the cathode strike the anode , and can cause parasitic ...
Secondary electrons are also the main means of viewing images in the scanning electron microscope (SEM). The range of secondary electrons depends on the energy. Plotting the inelastic mean free path as a function of energy often shows characteristics of the "universal curve" [1] familiar to electron spectroscopists and surface analysts.
The multipactor effect occurs when electrons accelerated by radio-frequency (RF) fields are self-sustained in a vacuum (or near vacuum) via an electron avalanche caused by secondary electron emission. [2] The impact of an electron to a surface can, depending on its energy and angle, release one or more secondary electrons into the vacuum. These ...
where is the breakdown voltage in volts, is the pressure in pascals, is the gap distance in meters, is the secondary-electron-emission coefficient (the number of secondary electrons produced per incident positive ion), is the saturation ionization in the gas at a particular / (electric field/pressure), and is related to the excitation and ...
The hole left behind the electron can give rise to secondary electron emission, or the so-called Auger effect, which may be visible even when the primary photoelectron does not leave the material. In molecular solids phonons are excited in this step and may be visible as satellite lines in the final electron energy.
Contrasting differences between discrete and continuous electron multipliers. An electron multiplier is a vacuum-tube structure that multiplies incident charges. [1] In a process called secondary emission, a single electron can, when bombarded on secondary-emissive material, induce emission of roughly 1 to 3 electrons.
This process is known as secondary electron emission. Once free of the cathode, the electric field accelerates electrons into the bulk of the glow discharge. Atoms can then be excited by collisions with ions, electrons, or other atoms that have been previously excited by collisions.
A dynode is an electrode in a vacuum tube that serves as an electron multiplier through secondary emission. The first tube to incorporate a dynode was the dynatron , an ancestor of the magnetron , which used a single dynode. [ 1 ]