gamma ray(redirected from Gamma particles)
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1. A photon of electromagnetic radiation of very short wavelength, less than about 0.01 nanometer, and very high energy, greater than about 100,000 electron volts. Gamma rays are emitted in the decay of certain radioactive nuclei and in electron-positron annihilation.
2. A narrow beam of such photons.
1. a highly penetrating photon of high frequency, usu. 1019 Hz or more, emitted by an atomic nucleus.
2. a stream of such photons.
A stream of electromagnetic radiation having wavelengths shorter than those of x-rays and therefore greater energy and penetrating power. Gamma rays are given off by unstable nuclei during radioactive decay. ♦ The emission of gamma rays by a nucleus is called gamma decay. Gamma decay does not change the atomic number or the mass number of an element. See more at radiation, radioactive decay.
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|Noun||1.||gamma ray - electromagnetic radiation emitted during radioactive decay and having an extremely short wavelength|
electromagnetic radiation, electromagnetic wave, nonparticulate radiation - radiation consisting of waves of energy associated with electric and magnetic fields resulting from the acceleration of an electric charge
electromagnetic spectrum - the entire frequency range of electromagnetic waves