What's the difference between alpha, beta, and gamma radiation?

Alpha radiation consists of helium nuclei, beta radiation is high-energy electrons, and gamma radiation is electromagnetic radiation.

Alpha radiation is the least penetrating of the three types and can be stopped by a sheet of paper or a few centimetres of air. It is highly ionising, meaning it can strip electrons from atoms and molecules, which can cause damage to living tissue. Alpha radiation is emitted by heavy, unstable nuclei, such as uranium and radium.

Beta radiation is more penetrating than alpha radiation and can be stopped by a few millimetres of aluminium. It is also ionising, but less so than alpha radiation. Beta radiation is emitted by unstable nuclei that have too many neutrons or protons, and the emission of beta particles helps to stabilise the nucleus.

Gamma radiation is the most penetrating of the three types and can only be stopped by thick layers of concrete or lead. It is not ionising, but it is highly energetic and can cause damage to living tissue by breaking chemical bonds. Gamma radiation is emitted by the nucleus of an atom in an excited state, and the emission of gamma rays helps to bring the nucleus back to its ground state.

In summary, alpha radiation is the least penetrating but most ionising, beta radiation is more penetrating but less ionising, and gamma radiation is the most penetrating but not ionising.