Editing Radiation (section)

=== Gamma radiation ===
{{Main|Gamma ray}}
[[File:Gamma radiation detected in an isopropanol cloud chamber.jpg|thumb|Gamma radiation detected in an [[isopropanol]] [[cloud chamber]].]]
Gamma (γ) radiation consists of photons with a wavelength less than {{val|3|e=−11|u=m}} (greater than 10<sup>19</sup>&nbsp;Hz and 41.4&nbsp;keV).<ref name="ICNIR2003">{{cite journal|url=https://www.who.int/peh-emf/meetings/archive/en/keynote3ng.pdf| title=Non-Ionizing Radiations – Sources, Biological Effects, Emissions and Exposures|journal= Proceedings of the International Conference on Non-Ionizing Radiation at UNITEN ICNIR2003 Electromagnetic Fields and Our Health|date=20–22 October 2003|author= Kwan-Hoong Ng}}</ref> Gamma radiation emission is a nuclear process that occurs to rid an unstable [[atomic nucleus|nucleus]] of excess energy after most nuclear reactions. Both alpha and beta particles have an electric charge and mass, and thus are quite likely to interact with other atoms in their path. Gamma radiation, however, is composed of photons, which have neither mass nor electric charge and, as a result, penetrates much further through matter than either alpha or beta radiation.

Gamma rays can be stopped by a sufficiently thick or dense layer of material, where the stopping power of the material per given area depends mostly (but not entirely) on the total mass along the path of the radiation, regardless of whether the material is of high or low density. However, as is the case with X-rays, materials with a high atomic number such as lead or [[depleted uranium]] add a modest (typically 20% to 30%) amount of stopping power over an equal mass of less dense and lower atomic weight materials (such as water or concrete). The atmosphere absorbs all gamma rays approaching Earth from space. Even air is capable of absorbing gamma rays, halving the energy of such waves by passing through, on the average, {{convert|500|ft|abbr=on}}.