Editing Radiation (section)

=== Beta radiation ===
{{Main|Beta decay}}
[[File:Electron detected in an isopropanol cloud chamber.jpg|thumb|[[Electrons]] (beta radiation) detected in an [[isopropanol]] [[cloud chamber]]]]
Beta-minus (β<sup>−</sup>) radiation consists of an energetic electron. It is more penetrating than alpha radiation but less than gamma. Beta radiation from [[radioactive decay]] can be stopped with a few centimetres of plastic or a few millimetres of metal. It occurs when a neutron decays into a proton in a nucleus, releasing the beta particle and an [[antineutrino]]. Beta radiation from [[linac]] accelerators is far more energetic and penetrating than natural beta radiation. It is sometimes used therapeutically in [[radiotherapy]] to treat superficial tumors.

Beta-plus (β<sup>+</sup>) radiation is the emission of [[positron]]s, which are the [[antimatter]] form of electrons. When a positron slows to speeds similar to those of electrons in the material, the positron will annihilate an electron, releasing two gamma photons of 511&nbsp;keV in the process. Those two gamma photons will be traveling in (approximately) opposite directions. The gamma radiation from positron annihilation consists of high energy photons, and is also ionizing.