"beta particle." YourDictionary, n.d. Web. 09 November 2018. <https://www.yourdictionary.com/beta-particle>.
beta particle. (n.d.). Retrieved November 09th, 2018, from https://www.yourdictionary.com/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.