What is the X in X-mas?
beta particle n.
A high-speed electron or positron, especially one emitted from the nucleus of an atom in radioactive decay.
|beta particle |
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. See more at radioactive decay.
electron (unit negative charge) or positron (unit positive charge) spontaneously emitted by certain unstable atomic nuclei in the radioactive disintegration process of beta decay (q.v.).