Beta rays (β)

Beta (β) rays or beta electrons are electrons emitted spontaneously by some radioactive nuclei with an excess of neutrons : This is beta-minus (β-) radioactivity, the minus reminding that the electric charge of the electron is negative. Nuclei with an excess of protons emit anti-electrons or positrons beta positrons : This is the beta- plus radioactivity (β+) , a form of radioactivity rare in Nature.