United States Nuclear Regulatory Commission - Protecting People and the Environment
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Gamma radiation

High-energy, short-wavelength, electromagnetic radiation emitted from the nucleus of an atom. Gamma radiation frequently accompanies emissions of alpha particles and beta particles, and always accompanies fission. Gamma rays are similar to x-rays, but are very penetrating and are best stopped or shielded by dense materials, such as lead or depleted uranium.

Page Last Reviewed/Updated Tuesday, October 28, 2014