Editing Particle radiation

{{Short description|Fast-moving particles with energy}}
{{Use dmy dates|date=June 2016}}

'''Particle radiation''' is the [[radiant energy|radiation]] of energy by means of fast-moving [[subatomic particle]]s. Particle radiation is referred to as a [[particle beam]] if the particles are all moving in the same direction, similar to a [[light beam]].

Due to the [[wave–particle duality]], all moving particles also have wave character. Higher energy particles more easily exhibit particle characteristics, while lower energy particles more easily exhibit wave characteristics.

==Types and production==
Particles can be [[charged particle|electrically charged]] or uncharged:

Particle radiation can be emitted by an unstable [[atomic nucleus]] (via [[radioactive decay]]), or it can be produced from some other kind of [[nuclear reaction]]. Many types of particles may be emitted:

*[[proton]]s and other [[hydrogen]] nuclei stripped of their electrons
*positively charged [[alpha particle]]s (α), equivalent to a [[helium-4]] nucleus
*[[helium]] ions at high energy levels
*[[HZE ions]], which are nuclei heavier than helium
*positively or negatively charged [[beta particle]]s (high-energy [[positron]]s β<sup>+</sup> or [[electron]]s β<sup>−</sup>; the latter being more common)
*high-speed electrons that are not from the [[beta decay]] process, but others such as [[internal conversion]] and [[Auger effect]]
*[[neutron]]s, subatomic particles which have no charge; [[neutron radiation]]
*[[neutrino]]s
*[[meson]]s
*[[muon]]s

Mechanisms that produce particle radiation include:
*[[alpha decay]]
*[[Auger effect]]
*[[beta decay]]
*[[cluster decay]]
*[[internal conversion]]
*[[neutron emission]]
*[[nuclear fission]] and [[spontaneous fission]]
*[[nuclear fusion]]
*[[particle collider]]s in which streams of high energy particles are smashed
*[[proton emission]]
*[[solar flares]]
*[[solar particle events]]
*[[supernova]] explosions
*Additionally, [[galactic cosmic rays]] include these particles, but many are from unknown mechanisms

Charged particles ([[electron]]s, mesons, [[proton]]s, alpha particles, heavier [[HZE ions]], etc.) can be produced by [[particle accelerator]]s. Ion irradiation is widely used in the [[semiconductor]] industry to introduce [[dopant]]s into
materials, a method known as [[ion implantation]].

Particle accelerators can also produce [[neutrino]] beams. Neutron beams are mostly produced by [[nuclear reactor]]s.

==Passage through matter==
[[File:Radioactivity and radiation.png|thumb|Graphic showing relationships between radioactivity and detected ionizing radiation]]
In [[radiation protection]], radiation is often separated into two categories, ''[[ionizing radiation|ionizing]]'' and ''[[non-ionizing radiation|non-ionizing]]'', to denote the level of danger posed to humans. [[Ionization]] is the process of removing electrons from atoms, leaving two electrically charged particles (an electron and a positively charged ion) behind.<ref name=":0">{{Cite web|title=ionizing radiation {{!}} Definition, Sources, Types, Effects, & Facts|url=https://www.britannica.com/science/ionizing-radiation|access-date=2021-02-27|website=Encyclopedia Britannica|language=en}}</ref> The negatively charged electrons and positively charged ions created by ionizing radiation may cause damage in living tissue. Basically, a particle is ionizing if its energy is higher than the [[Ionization potential|ionization energy]] of a typical substance, i.e., a few [[Electronvolt|eV]], and interacts with electrons significantly.

According to the [[International Commission on Non-Ionizing Radiation Protection]], electromagnetic radiations from ultraviolet to infrared, to radiofrequency (including microwave) radiation, static and time-varying electric and magnetic fields, and [[ultrasound]] belong to the non-ionizing radiations.<ref>{{Cite web|title=ICNIRP {{!}} Frequencies|url=https://www.icnirp.org/en/frequencies/index.html|access-date=2021-02-27|website=www.icnirp.org}}</ref>
 
The charged particles mentioned above all belong to the ionizing radiations. When passing through matter, they [[ionization|ionize]] and thus lose energy in many small steps. The distance to the point where the charged particle has lost all its energy is called the [[range (particle radiation)|range]] of the particle. The range depends upon the type of particle, its initial energy, and the material it traverses. Similarly, the energy loss per unit path length, the '[[stopping power (particle radiation)|stopping power]]', depends on the type and energy of the charged particle and upon the material. The stopping power and hence, the density of ionization, usually increases toward the end of range and reaches a maximum, the [[Bragg Peak]], shortly before the energy drops to zero.<ref name=":0" />

==See also==
*[[Geiger counter]]
*[[Ion chamber]]
*[[Nuclear engineering]]
*[[Nuclear physics]]
*[[Particle accelerator]]
*[[Particle decay]]
*[[Physics]]
*[[Proportional counter]]
*[[Radiation]]
*[[Radiation therapy]]
*[[Radioactivity]]
*[[Stopping power (particle radiation)|Stopping power of radiation particles]]

==References==
{{Reflist}}

==External links==
*[http://bohr.inf.um.es/MELF-GOS.html Stopping power and energy loss straggling calculations of ion beams in solids by MELF-GOS model] {{Webarchive|url=https://web.archive.org/web/20100925154955/http://bohr.inf.um.es/MELF-GOS.html |date=25 September 2010 }}

{{Radiation}}

[[Category:Radioactivity]]