Secondary emission
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In particle physics, secondary emission is a phenomenon where primary incident particles of sufficient energy, when hitting a surface or passing through some material, induce the emission of secondary
The display on an oscilloscope at normal intensity.
The same tube with greater intensity. The disk around the dot in the center is due to secondary emission. Electrons are struck off the screen and travel backwards into the tube. The voltage across the tube causes them to be accelerated forward again, striking the screen over a wide area.[citation needed]
Photomultiplier tube
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Photomultiplier tubes are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. They are members of the class of vacuum tubes, m
Secondary emission
…secondary emission yield. If the secondary particles are ions, the effect is termed secondary ion emission. 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…
Photomultiplier
Dynodes inside a photomultiplier tube
Fig. 2: Typical photomultiplier voltage divider circuit using negative high voltage.
Internal metallisation as a protective screen against unwanted light sources