Editing Particle beam (section)

==Sources==
[[Charged particles]] such as [[electron]]s, [[positron]]s, and [[proton]]s may be separated from their common surroundings. This can be accomplished by processes such as [[thermionic emission]] or [[arc discharge]]. The following devices are commonly used as sources for particle beams:
* [[Ion source]]
* [[Cathode-ray tube]], or more specifically in one of its parts called [[electron gun]]. This is also part of traditional television and computer screens.
* [[Photocathode]]s may also be built in as a part of an [[electron gun]], using the [[photoelectric effect]] to separate particles from their substrate.<ref>T. J. Kauppila et al. (1987), ''A pulsed electron injector using a metal photocathode irradiated by an excimer laser'', Proceedings of Particle Accelerator Conference 1987</ref>
* [[Neutron]] beams may be created by energetic [[proton beam]]s which impact on a target, e.g. of [[beryllium]] material. (see article [[Particle therapy]])
* Bursting a petawatt laser onto a [[titanium]] foil to produce a proton beam<!-- and also water, and organic residue on the residual titanium foil as a side effect -->.<ref>[https://www.nextbigfuture.com/2018/04/petawatt-proton-beams-at-lawrence-livermore.html Petawatt proton beams at Lawrence Livermore]</ref>