Electron emission
Electron emission is the process of sending electrons out of a material . For their formation when neutrons decay, see beta decay .
The electrons can either secondary electrons or by high electrical field strengths (→ field emission ) or high temperatures (→ Thermal emission or thermionic emission from) the electron shells are released. The latter is used for hot cathodes . In addition, there is the photoemission by photomultiplier .
Secondary electrons are created by the external photoelectric effect or by the impact of particles, especially ions (in the glow discharge of cold cathode lamps) or (primary) electrons. The latter happens several times in a row in the secondary electron multiplier, which is why it can be used for signal amplification. The effect is used for imaging in the scanning electron microscope .
Secondary electron emission occurs in normal electron tubes at the anode or at strongly positive electrodes and is undesirable here.
literature
- Wolfgang Finkelnburg: Introduction to Atomic Physics. Eleventh and twelfth completely revised and expanded editions, Springer Verlag Berlin Heidelberg, Berlin Heidelberg 1976, ISBN 978-3-540-03791-0 .
- Ernst Lecher, Adolf Smekal (Ed.): Textbook of Physics. Volume 2, Walter de Gruyter & Co, Berlin and Leipzig 1928.
- Hajo Bruining: The secondary electron emission of solid bodies. Springer Verlag, Berlin 1942.
See also
Web links
- Experiments to measure the thermal electron emission of graphite, silicon and silicon carbide (accessed on September 9, 2016)
- Field-induced electron emission from diamond layers and carbon nanostructures (accessed September 9, 2016)
- Microscopic investigation of ferroelectric electron emission from the free surface of triglyzine sulfate (accessed September 9, 2016)