alpha particle

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alpha particle

n.
A positively charged subatomic particle, composed of two protons and two neutrons, identical with the nucleus of the helium isotope He-4.

alpha particle

n
(General Physics) a helium-4 nucleus, containing two neutrons and two protons, emitted during some radioactive transformations

al′pha par`ticle


n.
a positively charged particle consisting of two protons and two neutrons, emitted in radioactive decay or nuclear fission; the nucleus of a helium atom.
[1900–05]

alpha particle

A positively charged particle that consists of two protons and two neutrons bound together. It is emitted by the nucleus of some elements undergoing radioactive decay and is identical to the nucleus of a helium atom. Alpha particles are the slowest and least penetrating forms of nuclear radiation. ♦ The process by which a radioactive element emits an alpha particle is called alpha decay. Alpha decay results in the atomic number of the atom being decreased by two and the mass number being decreased by four. See more at radiation, radioactive decay.

alpha particle

A helium nucleus that has a positive electric charge.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.alpha particle - a positively charged particle that is the nucleus of the helium atomalpha particle - a positively charged particle that is the nucleus of the helium atom; emitted from natural or radioactive isotopes
subatomic particle, particle - a body having finite mass and internal structure but negligible dimensions
References in periodicals archive ?
The swiftness of that implosion would cause the hydrogen fuel to ignite in a brief, self-sustaining fusion reaction releasing a helium nucleus, a neutron--and up to 100 times as much energy as the laser delivered.
The energy from a single deuteriumtritium fusion reaction is carried away by a neutron and a helium nucleus.
When they fuse, the two nuclei join and produce a helium nucleus, a high-energy neutron and a much larger amount of energy than was needed to fuse the two nuclei.