What is radiation? What are the different types of radiation and what are their uses? Find out below!
What is radiation?
Radiation is the emanation of energy in the form of waves or particles.
Background radiation is always present on Earth, arriving from space, present in the ground and water on Earth, and found in the human body naturally.
Man-made radiation comes from nuclear weapons tests, nuclear reactors and accidents, and of course, radiation used in diagnostic and therapeutic medicine.
Types of radiation
There are many types of radiation, including electromagnetic, which includes radio waves, microwaves, visible light, ultraviolet, x-rays, and gamma radiation, acoustic such as ultrasound, sound, and seismic waves, and particle radiation.
Regardless of the source, all forms of radiation can be divided into two main categories: ionizing and non-ionizing.
Ionizing and non-ionizing radiation
Ionizing radiation is highly energetic and is able to break electrons off atoms to create ions, while non-ionizing is lower-energy and unable to create ions.
This distinction is important, as ionizing radiation is highly capable of damaging human DNA and other cellular molecules, leading to increased risks of cancer and acute radiation syndrome (ARS).
Ionizing radiation comes mainly from the decay of radioactive substances that gives off alpha, beta, or gamma radiation.
Alpha particles are essentially helium-4 nuclei, consisting solely of 2 protons and 2 neutrons. They are produced when some radioactive isotopes decay into more stable products.
Because these particles have mass and charge, they interact with other matter, including air, and can only penetrate a very small distance through air and an even smaller distance through other low density materials.
They cannot penetrate human skin. Therefore, even though alpha particles are ionizing, they are only dangerous when substances that give off this type of radiation are swallowed or breathed in, putting them in close proximity to sensitive tissue.
Common sources of alpha radiation are isotopes of radium, radon, polonium, uranium, plutonium, thorium, and other radioactive isotopes.
Beta particles are either positively-charged positrons or negatively-charged electrons from the nuclei of some atoms. They occur when a neutron decays into a proton inside the nucleus, which releases a beta particle and an antineutrino.
Beta particles can penetrate matter more than alpha particles but is able to be stopped by thin sheets of wood or metal. Like alpha radiation, the main danger of beta particles is through ingestion.
Common sources of beta radiation are certain isotopes of strontium, yttrium, tritium, carbon, potassium, and nickel.
Gamma radiation is a wave, rather than a particle, like alpha and beta radiation. It is on the high-energy end of the electromagnetic spectrum, just past x-rays.
The emission of gamma radiation comes from an unstable nucleus getting rid of excess energy during nuclear decay.
Composed of photons, gamma radiation is able to penetrate through matter much more than alpha and beta radiation. They can, however, be stopped by lead and iron, like x-rays.
Common sources of gamma radiation are isotopes of cesium, barium, iodine, and lanthanum. Contrary to popular belief, gamma radiation cannot give anyone superpowers!
Uses of radiation
While radiation can cause radiation sickness and even death, controlled use of radiation has many beneficial applications in fields such as construction, diagnostic and therapeutic medicine, and research.