gamma ray

American  

noun

Physics.

1. a photon of penetrating electromagnetic radiation gamma radiation emitted from an atomic nucleus.

2. a photon emitted by an electron as a result of internal conversion.

3. electromagnetic radiation with wavelengths shorter than approximately one tenth of a nanometer.

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gamma ray Scientific  

1. A stream of high-energy electromagnetic radiation given off by an atomic nucleus undergoing radioactive decay. Because the wavelengths of gamma rays are shorter than those of x-rays, gamma rays have greater energy and penetrating power than x-rays. Gamma rays are emitted by pulsars, quasars, and radio galaxies but cannot penetrate the Earth's atmosphere.

2. See more at radioactive decay

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Etymology

Origin of gamma ray

First recorded in 1900–05

Example Sentences

Using rare isotope beams at Michigan State University and highly sensitive gamma ray detectors, the team measured the lifetimes of excited nuclear states with precision on the scale of picoseconds.

From Science Daily • Mar. 8, 2026

However, theory suggests that when two WIMPs collide, they annihilate each other and release energetic particles, including gamma ray photons.

From Science Daily • Nov. 29, 2025

Totani explains that the gamma ray pattern cannot be easily matched to other known sources or more common astrophysical processes.

From Science Daily • Nov. 29, 2025

A gamma ray detector on a device developed by a Cornish company is being used to assess soil quality.

From BBC • Nov. 26, 2024

“Unfortunately, between the man and yourself, there will be a gamma ray field.”

From "I, Robot" by Isaac Asimov