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ionizing radiation[′ī·ə‚niz·iŋ ‚rād·ē′ā·shən]
any radiation whose interaction with a medium ultimately leads to the ionization of atoms and molecules of the medium. Types of ionizing radiation include electromagnetic radiation, X rays, gamma radiation, and laser radiation, as well as fluxes of a-particles, electrons, positrons, protons, neutrons, and other neutral and charged particles. Charged particles ionize the atoms of the medium directly upon collision if their kinetic energy is sufficient for ionization. When neutral particles (neutrons) or photons (quanta of X rays or y-radiation) pass through the medium, ionization is brought about by the secondary charged particles that form from the interaction of the primary particles with the medium.
Ionizing radiation plays an important role in various physical and chemical processes and in biology, medicine, agriculture, and industry. Many chemical reactions take place more readily or at considerably lower temperatures and pressures under the influence of ionizing radiation. Ionizing radiation is used in sterilization, pasteurization, and preservation of foods and pharmaceuticals. It produces various mutations in microorganisms and plants.
At the same time, ionizing radiation exerts a destructive ac-tion on matter. [10–1103-2; updated]