One form of nuclear radiation, beta decay, occurs when a neutron
changes into a proton, an electron and a neutral particle called a
neutrino. When this change happens to a neutron within the nucleus
of an atom, the proton remains behind in the nucleus while the
electron and neutrino are ejected from the nucleus. The ejected
electron is called a beta particle. One nucleus that exhibits beta
decay is the isotope of hydrogen 3H, called tritium,
whose nucleus consists of...