beta particle

American  

noun

Physics.

1. an electron or positron emitted from an atomic nucleus in a certain type of radioactive decay.

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beta particle British  

noun

1. a high-speed electron or positron emitted by a nucleus during radioactive decay or nuclear fission

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beta particle Scientific  

1. 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.

2. See more at radioactive decay

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Etymology

Origin of beta particle

First recorded in 1900–05

Example Sentences

The Nuclear Regulatory Commission says that tritium emits a weak form of radiation, a low-energy beta particle similar to an electron.

From Reuters • Aug. 18, 2011

Each beta particle emitted meant that a captured neutron had changed into a proton.

From Time Magazine Archive

The beta particle has only about one seven-thousandth the mass of the alpha particle, but its velocity is very much greater, as much as eight-tenths the velocity of light.

From Worldwide Effects of Nuclear War: Some Perspectives by U.S. Arms Control and Disarmament Agency

Beta--Another form of radioactive decay is the emission of a beta particle, or electron.

From Worldwide Effects of Nuclear War: Some Perspectives by U.S. Arms Control and Disarmament Agency

One beta particle is then lost and UX2 belonging to the fifth group is formed.

From A Brief Account of Radio-activity by Venable, Francis Preston