Types Of Radiation
When people bring up the topic of radiation, it is important to distinguish between types of radiation. Physically, types of radiation can be sorted into two categories: 1. Electromagnetic radiation and 2. Particle radiation.
Electromagnetic radiation can be thought of as photons vibrating at specific frequencies, and includes Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays and Gamma rays. Higher frequency waves such as Ultraviolet, X-rays and Gamma rays carry more energy and thus greater potential to affect living tissue.
Particle radiation is generally associated with radioactivity and because the particles are charged atomic fragments, are often referred to as Ionizing radiation.
Ionizing Types Of Radiation
Ionizing types of radiation are normally associated with radioactivity, and are sorted into categories according to penetrating power. The least penetrating is Alpha radiation, which travels only a short distance in air, and is easily stopped by paper. Slightly more penetrating is Beta radiation, which can be stopped by tinfoil or skin, but which may cause external burns in sufficient quantities. Of all the types of radiation, Gamma radiation is the most penetrating and can generally only be stopped by several feet of water or earth.
Types Of Radiation: Alpha Radiation
Alpha Radiation is the least penetrating and consists of two protons and two neutrons, in other words, a Helium nucleus without its electrons. It can be stopped by paper and skin. Internally however, an Alpha-emitter causes significant damage two ways:
- When the Alpha particle strikes adjacent tissue
- When the atom that emitted it recoils and also strikes adjacent tissue
Both of the above can cause damage to DNA both directly and through the creation of “free radicals” (molecular fragments with available valence electrons).
Types Of Radiation: Beta Radiation
Beta Radiation penetrates paper and some layers of living tissue and consists of either an electron or a positron and an antineutrino. It can cause damage by disrupting cell functions and DNA.
Types Of Radiation: Gamma Radiation
Gamma Radiation is the most penetrating and consists of high-frequency electromagnetic waves (comparable to X-rays, but more so). It is stopped by thick masses of metal, water or earth (rock). External exposure causes diffuse damage throughout the body and internal exposure results in both diffuse and localized damage, generally in the range between 3 and 10 MeV. (The Chernobyl workers reported both immediate effects such as the inability to feel their teeth and subsequent effects such as feeling drained and the appearance of burn marks. Later, they were subject to a variety of cancers, organ damage and premature aging).