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beta particle,one of the three types of radiation resulting from natural radioactivityradioactivity,
spontaneous disintegration or decay of the nucleus of an atom by emission of particles, usually accompanied by electromagnetic radiation. The energy produced by radioactivity has important military and industrial applications.
..... Click the link for more information. . Beta radiation (or beta rays) was identified and named by E. Rutherford, who found that it consists of high-speed electronselectron,
elementary particle carrying a unit charge of negative electricity. Ordinary electric current is the flow of electrons through a wire conductor (see electricity). The electron is one of the basic constituents of matter.
..... Click the link for more information. . Unlike alpha and gamma particles, whose energy can be explained as the difference of the energies of the radioactive nucleus before and after emission, beta particles emerge with a variable energy. This apparent violation of the law of conservation of energy (see conservation lawsconservation laws,
in physics, basic laws that together determine which processes can or cannot occur in nature; each law maintains that the total value of the quantity governed by that law, e.g., mass or energy, remains unchanged during physical processes.
..... Click the link for more information. ) led to the hypothesis that a second undetected particle, the neutrinoneutrino
[Ital.,=little neutral (particle)], elementary particle with no electric charge and a very small mass emitted during the decay of certain other particles. The neutrino was first postulated in 1930 by Wolfgang Pauli in order to maintain the law of conservation of energy
..... Click the link for more information. , is emitted along with the electron and shares the total available energy. In some forms of induced, or artificial, radioactivity, the electron's antiparticleantiparticle,
elementary particle corresponding to an ordinary particle such as the proton, neutron, or electron, but having the opposite electrical charge and magnetic moment.
..... Click the link for more information. , the positron, is emitted from the excited nucleus; the positron in this case is also called a beta particle and denoted by β+ (the ordinary beta particle is β−).
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beta particleAn energetic electron or positron ejected by beta decay.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
beta particle[′bād·ə ‚pard·ə·kəl]
An electron or positron emitted from a nucleus during beta decay.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
Physics a high-speed electron or positron emitted by a nucleus during radioactive decay or nuclear fission
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005