GammaAbstrahlung

GammaAbstrahlung, or gamma radiation, denotes the emission of high-energy photons produced when an atomic nucleus or, less commonly, an atomic electron system releases excess energy. In most cases, gamma rays originate from nuclear de-excitation: after a beta decay or other transformation leaves a nucleus in an excited state, it emits one or more photons to reach its ground state. Internal conversion may compete with photon emission, ejecting an atomic electron instead of a gamma ray.

Gamma rays have energies ranging from tens of keV to several MeV and are highly penetrating. Their interactions with matter depend on energy and atomic number, with the photoelectric effect, Compton scattering, and electron-positron pair production being the dominant processes in different regimes. Shielding requires dense materials (for example lead) and sufficient thickness, along with minimizing exposure through distance and time.

Natural gamma sources include isotopes in the uranium and thorium decay chains and potassium-40. Artificial gamma emitters such as cobalt-60, cesium-137, and technetium-99m are widely used in medicine and industry.

Detection and analysis rely on gamma-ray spectrometry with scintillation detectors (such as NaI(Tl)) or semiconductor detectors (high-purity germanium). The observed energy lines identify isotopes and enable activity measurements.

Applications span medical imaging and radiotherapy, industrial radiography, homeland security, and scientific research. Safety considerations emphasize radiation protection, monitoring, shielding design, and adherence to regulatory limits.

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