Particles can be electrically charged or uncharged:
Particle radiation can be emitted by an unstable atomic nucleus (via radioactive decay), or it can be produced from some other kind of nuclear reaction. Many types of particles may be emitted:
*protons and other hydrogen nuclei stripped of their electrons
*positively charged alpha particles (α), equivalent to a helium-4 nucleus
*helium ions at high energy levels
*HZE ions, which are nuclei heavier than helium
*positively or negatively charged beta particles (high-energy positrons β or electrons β; the latter being more common)
*high-speed electrons that are not from the beta decay process, but others such as internal conversion and Auger effect
*neutrons, subatomic particles which have no charge; neutron radiation
*neutrinos
*mesons
*muons
Mechanisms that produce particle radiation include:
*alpha decay
*Auger effect
*beta decay
*cluster decay
*internal conversion
*neutron emission
*nuclear fission and spontaneous fission
*nuclear fusion
*particle colliders in which streams of high energy particles are smashed
*proton emission
*solar flares
*solar particle events
*supernova explosions
*Additionally, galactic cosmic rays include these particles, but many are from unknown mechanisms
Charged particles (electrons, mesons, protons, alpha particles, heavier HZE ions, etc.) can be produced by particle accelerators. Ion irradiation is widely used in the semiconductor industry to introduce dopants into
materials, a method known as ion implantation.
Particle accelerators can also produce neutrino beams. Neutron beams are mostly produced by nuclear reactors.