gamma ray

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gamma ray

n.
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.

gam′ma-ray′ adj.

gam′ma ray`


n.
1. a highly penetrating photon of high frequency, usu. 1019 Hz or more, emitted by an atomic nucleus.
2. a stream of such photons.
[1900–05]

gamma ray

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.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.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
References in periodicals archive ?
The new finding "is exciting because gamma-ray bursts are showing them selves as a unique probe of the early universe that really hadn't been considered," Joshua Bloom of the University of California, Berkeley reported on January 4.
Astronomers were drawn to the distant explosion by a gamma-ray burst--radiation of extremely high energy.
Symposium on High Energy Gamma-Ray Astronomy (2d: 2004: Heidelberg, Germany) Ed.
where q is the amount of charge created by the photocathode per detected gamma-ray, I is the average photocurrent per detector and [f.sub.B] is the sampling bandwidth, set by the 0.4 ms time bin width.
It was in order to detect these extremely short flashes, and hence gamma-ray emissions, that fourteen countries set up the HESS array(1), the world's largest gamma-ray observatory, in Namibia in 2002.
Although this Gamma-ray background radiation has been studied in extensive detail since the Fermi Satellite equipped with the Large Area Telescope was launched in 2008, its origin remains an enduring mystery.
Major improvements to methods used to process observations from NASA's Fermi Gamma-ray Space Telescope have yielded an expanded, higher-quality set of data that allows astronomers to produce the most detailed census of the sky yet made at extreme energies.
28 ( ANI ): Researchers have claimed that gamma-ray photons observed from the center of the Milky Way Galaxy are consistent with the intriguing possibility of dark matter annihilation.
The speculative claim, by an Italian team looking at high-energy emission from blazars, is that gamma-ray photons coming from close to a galaxy's central black hole may switch between being photons and an exotic, as-yet undetected particle that goes beyond the Standard Model of particle physics.
But both teams note that they are most excited about the unexpected clockwork pattern of the gamma-ray emission, which always seems to occur during a lull in high-energy X-rays and just before the onset of powerful radio jets.
NIST has recently revised and published a key Measurement Services Guide, NIST Special Publication 250-58, which describes completely the x-ray and gamma-ray calibration services provided at NIST.
Gamma-ray binary is the name given to a system of two stars, one a normal star and the other either a neutron star or a black hole, whose radiative output is dominated by gamma-rays - the highest-energy form of light.

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