A beta particle is a type of particle emitted during beta decay, a form of radioactive decay. Beta particles can be either electrons or positrons, depending on the type of beta decay.
In beta-minus decay, a neutron in the nucleus is converted into a proton, emitting an electron and an antineutrino:
n → p + e- + ν-bar
The emitted electron is a beta particle. It has a negative charge and a mass of approximately 9.11 x 10^-31 kilograms, which is about 1/1836 the mass of a proton. The beta particle carries away some of the excess energy from the nucleus, reducing its energy and making it more stable.
In beta-plus decay, a proton in the nucleus is converted into a neutron, emitting a positron and a neutrino:
p → n + e+ + ν
The emitted positron is also a beta particle. It has a positive charge and the same mass as an electron.
Beta particles can be detected using a variety of instruments, including Geiger counters and scintillation detectors. Beta decay and beta particles have many practical applications in nuclear physics. Read more betatron.
