Particle 5 : Beta Particle: An elementary particle, emitted from a nucleus during radioactive decay, with a single electrical charge and a mass equal to that of a proton
NFPA 801 Standard for Fire Protection for Facilities Handling Radioactive Materials, 2008 ed. https://www.nfpa.org/Assets/files/AboutTheCodes/80 1/FIF-AAA_ROPagenda_6-11.pdf, (Std: Fr Prac for Faclty Hndlg Radioactive Mtrls - Amer) {348 NFC}