alpha particle

alpha particle

n.

A positively charged nuclear particle, indistinguishable from a helium atom nucleus and consisting of two protons and two neutrons.

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alpha particle,

a particle emitted from an atom during one kind of radioactive decay. It consists of two protons and two neutrons, the equivalent of a helium nucleus. Ordinarily, alpha particles are a weak form of radiation with a short range and are not considered hazardous unless inhaled or ingested.

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particle,

n a small amount of material.

particle, alpha,

n (alpha ray, alpha radiation) a positively charged particulate ionizing radiation consisting of helium nuclei (two protons and two neutrons) traveling at high speeds. These rays are emitted from the nucleus of an unstable element.

particle, beta,

n (beta ray, beta radiation) a particulate ionizing radiation consisting of either negative electrons (negatrons) or positive electrons (positrons) emitted from the nucleus of an unstable element. This phenomenon is called
beta decay.