Particle beam: Difference between revisions

A '''particle beam''' is a stream of [[charged particle|charged]] or [[neutral particle]]s. In [[Particle accelerator|particle accelerators]], inthese manyparticles casescan movingmove atwith neara velocity close to the [[speed of light]]. There is a difference between the creation and control of [[charged particle beam]]s and neutral particle beams, as only the first type can be manipulated to a sufficient extent by devices based on [[electromagnetism]]. The manipulation and diagnostics of charged particle beams at high kinetic energies using [[particle accelerator]]s are main topics of [[accelerator physics]].

* [[ionIon source]]

* [[cathode Cathode-ray tube]], or more specifically in one of its parts called [[electron gun]]. This is also part of traditional television and computer screens.

* [[photocathodePhotocathode]]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 Petawattpetawatt Laserlaser onto a [[Titaniumtitanium]] foil to produce a proton beams,beam<!-- and also water, and organic compose 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>

==AccelerationManipulation==

Charged beams may be further accelerated by use of high resonant, sometimes also [[superconducting]], [[microwave cavity|microwave cavities]]. These devices accelerate particles by interaction with an [[electromagnetic field]]. Since the [[wavelength]] of hollow macroscopic, conducting devices is in the [[radio frequency]] (RF) band, the design of such cavities and other RF devices is also a part of accelerator physics.

More recently, [[plasma acceleration]] has emerged as a possibility to accelerate particles in a [[plasma (physics)|plasma]] medium, using the [[Radiant energy|electromagnetic energy]] of pulsed high-power [[laser]] systems or the [[kinetic energy]] of other charged particles. This technique is under active development, but cannot provide reliable beams of sufficient quality at present.

==Usage=Guidance===

[[Electron beamsbeam]]s are employed in [[synchrotron light sourcessource]]s to produce electromagnetic[[X-ray|X-ray radiation]] with a continuous [[spectrum]] over a wide [[frequency]] band which is called [[synchrotron radiation]]. This X-ray radiation may beis used at [[beamline]]s of the synchrotron storagelight ringsources for a variety of experiments[[spectroscopy|spectroscopies]] ([[XAS]], [[XANES]], [[EXAFS]], [[X-ray fluorescence|''μ''-XRF]], [[X-ray crystallography|''μ''-XRD]]) in order to probe and to characterize the structure and the chemical speciation of solids and biological materials.

Though particle beams are perhaps most famously employed as weapon systems in [[science fiction]], theThe U.S. [[Defense Advanced Research Projects Agency|Advanced Research Projects Agency]] started work on [[particle beam weapon]]s in 1958.<ref name=roberds84>{{cite journal | last=Roberds | first=Richard M. | year=1984 | title=Introducing the Particle-Beam Weapon | journal=Air University Review | volume=July–August | url=http://www.airpower.maxwell.af.mil/airchronicles/aureview/1984/jul-aug/roberds.html | access-date=2005-01-03 | archive-url=https://web.archive.org/web/20120417021903/http://www.airpower.maxwell.af.mil/airchronicles/aureview/1984/jul-aug/roberds.html | archive-date=2012-04-17 | url-status=dead }}</ref> The general idea of such weaponry is to hit a target object with a stream of accelerated particles with high [[kinetic energy]], which is then transferred to the atoms, or molecules, of the target. The power needed to project a high-powered beam of this kind surpasses the production capabilities of any standard battlefield powerplant,<ref name=roberds84/> thus such weapons are not anticipated to be produced in the foreseeable future.