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 ?
Since alpha particles only travel short distances of between 2 and 5 cell diameters, there is less chance of damaging healthy tissue with this type of therapy.
Carbon-12, an essential element we're all made of, can only form when three alpha particles, or helium-4 nuclei, combine in a very specific way.
Sigmar made important contributions to the understanding of collisional transport in tokamaks and the behavior of alpha particles in fusing plasmas, and played a leadership role in the development of an edge and divertor physics program in the U.
Some studies have suggested that the alpha particles ejected when radon decays may rank second only to tobacco smoke as a source of lung cancer (SN: 8/15/87, p.
After a short drive the preceding day to get within arm's reach of the football-size rock, Curiosity put its Alpha Particle X-Ray Spectrometer (APXS) instrument in contact with the rock during the rover's 46th Martian day, or sol.
For example, uranium-238 (element number 92), which is used in nuclear reactors, loses an alpha particle to become thorium-234 (element number 90).
Will a high density of energetic alpha particles destabilize waves and degrade alpha confinement so as to reduce the efficiency of alpha particle heating?
Checkouts in the next several days will include using the turret's Mars Hand Lens Imager to observe its calibration target and the Canadian-built Alpha Particle X-Ray Spectrometer to read what chemical elements are present in the instrument's calibration target.
Over the course of a lifetime, many people receive alpha particle hits to a proportion of their cells similar to that in the study.