gamma ray

noun Physics.

a photon of penetrating electromagnetic radiation (gamma radiation) emitted from an atomic nucleus.
a photon emitted by an electron as a result of internal conversion.
electromagnetic radiation with wavelengths shorter than approximately one tenth of a nanometer.

Origin of gamma ray

First recorded in 1900–05

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Well, maybe it was a gamma-ray burst, or maybe it was something else, cautioned some others.
The Gamma-Ray Burst That Wasn’t
Matthew R. Francis
June 1, 2014

The figure on the next page shows the gamma-ray spectrum for the patient.
The Atomic Fingerprint
Bernard Keisch
Meanwhile they amused themselves occasionally by planting a gamma-ray bomb in each of Mars' major cities.
The Ultimate Weapon
John Wood Campbell
A source of neutrons to activate the material and a gamma-ray spectrometer to measure the radiation from the material afterwards.
The Atomic Fingerprint
Bernard Keisch
Then you place each card, in turn, on a holder close to the gamma-ray detector for a period of 10 minutes.
The Atomic Fingerprint
Bernard Keisch
Gamma-ray spectra are collected all day, first from a sample, then from its accompanying standard.
The Atomic Fingerprint
Bernard Keisch

gamma ray in Medicine

Electromagnetic radiation emitted from the nucleus of an atom by radioactive decay and having energies in a range from ten thousand (104) to ten million (107) electron volts.

gamma ray in Science

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. See more at radioactive decay.