page_title: Beta particle
section_title: Detection and measurement
hierarchical_section_title: Beta particle / Interaction with other matter / Detection and measurement
caption_attribution_description: English: Beta radiation detected in an isopropanol cloud chamber (after insertion of an artificial source strontium-90)
context_page_description: A beta particle, also called beta ray or beta radiation, is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay. There are two forms of beta decay, β⁻ decay and β⁺ decay, which produce electrons and positrons respectively.
  Beta particles with an energy of 0.5 MeV have a range of about one metre in air; the distance is dependent on the particle energy.
  Beta particles are a type of ionizing radiation and for radiation protection purposes are regarded as being more ionising than gamma rays, but less ionising than alpha particles. The higher the ionising effect, the greater the damage to living tissue, but also the lower the penetrating power of the radiation.
context_section_description: The ionizing or excitation effects of beta particles on matter are the fundamental processes by which radiometric detection instruments detect and measure beta radiation. The ionization of gas is used in ion chambers and Geiger-Müller counters, and the excitation of scintillators is used in scintillation counters.
  The following table shows radiation quantities in SI and non-SI units:
  The gray (Gy),  is the SI unit of absorbed dose, which is the amount of radiation energy deposited in the irradiated material. For beta radiation this is numerically equal to the equivalent dose measured by the sievert, which indicates the stochastic biological effect of low levels of radiation on human tissue. The radiation weighting conversion factor from absorbed dose to equivalent dose is 1 for beta, whereas alpha particles have a factor of 20, reflecting their greater ionising effect on tissue.
  The rad is the deprecated CGS unit for absorbed dose and the rem is the deprecated CGS unit of equivalent dose, used mainly in the USA.
caption: Beta radiation detected in an isopropanol cloud chamber (after insertion of an artificial source strontium-90)
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