Particle radiation
Particle radiation is the radiation of energy by means of fast-moving subatomic particles. Particle radiation is referred to as a particle beam if the particles are all moving in the same direction, similar to a light beam.
Due to the wave–particle duality, all moving particles also have wave character. Higher energy particles more easily exhibit particle characteristics, while lower energy particles more easily exhibit wave characteristics.
Types and production
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 collidersin which streams of high energy particles are smashed
- proton emission
- solar flares
- solar particle events
- supernova explosions
- Additionally, galactic cosmic raysinclude these particles, but many are from unknown mechanisms
Charged particles (
Particle accelerators can also produce neutrino beams. Neutron beams are mostly produced by nuclear reactors.
Passage through matter
In
According to the International Commission on Non-Ionizing Radiation Protection, electromagnetic radiations from ultraviolet to infrared, to radiofrequency (including microwave) radiation, static and time-varying electric and magnetic fields, and ultrasound belong to the non-ionizing radiations.[2]
The charged particles mentioned above all belong to the ionizing radiations. When passing through matter, they
See also
- Geiger counter
- Ion chamber
- Nuclear engineering
- Nuclear physics
- Particle accelerator
- Particle decay
- Physics
- Proportional counter
- Radiation
- Radiation therapy
- Radioactivity
- Stopping power of radiation particles
References
- ^ a b "ionizing radiation | Definition, Sources, Types, Effects, & Facts". Encyclopedia Britannica. Retrieved 27 February 2021.
- ^ "ICNIRP | Frequencies". www.icnirp.org. Retrieved 27 February 2021.