an electron or positron emitted from an atomic nucleus in a certain type of radioactive decay.
A Brief Account of Radio-activity Francis Preston Venable
a high-speed electron or positron emitted by a nucleus during radioactive decay or nuclear fission
A high-speed electron or positron, usually emitted by an atomic nucleus undergoing radioactive decay. Beta particles are given off naturally by decaying neutrons in radioactive atoms and can be created in particle accelerators. Beta particles have greater speed and penetrating power than alpha particles but can be stopped by a sheet of aluminum that is 2 to 3 mm thick. See more at radioactive decay.
- Beta radiation
beta radiation beta radiation [(bay-tuh)] Note: Beta radiation, unlike alpha radiation, has some penetrating power and can pass through clothing and wooden walls.
- Beta ray
a stream of beta particles. Historical Examples The Breath of Life John Burroughs noun a stream of beta particles beta ray A stream of beta particles.
any of several marsupials of the genus Bettongia, of Australia and nearby regions, comprising the short-nosed rat-kangaroos, characterized by short, rounded ears, long hind feet, and a naked muzzle tip: all four species are endangered. noun a species of rat kangaroo of Australia having a short nose
- Beta rhythm
a pattern of high-frequency brain waves (beta waves) observed in normal persons upon sensory stimulation, especially with light, or when they are engaging in purposeful mental activity. noun (physiol) the normal electrical activity of the cerebral cortex, occurring at a frequency of 13 to 30 hertz and detectable with an electroencephalograph See also brain wave