What is radiation?

Radiation is a naturally occurring type of energy. It can be released by unstable forms of atoms, the basic units of matter, as they change into more stable forms. The energy released is emitted as either waves (such as X-rays or gamma rays) or particles (for example alpha and beta radiation). The three most common types of radiation are:

• Alpha particles, which are the largest and slowest atomic particles. They can travel only a few inches through air. They can be stopped by a sheet of paper or the outer layers of skin.
• Beta particles are smaller and faster than alpha particles and can travel further in air. They can easily be stopped by a thin shield such as a sheet of aluminum foil.
• Gamma radiation, which consists of gamma rays rather than atomic particles. Gamma rays are a type of electromagnetic wave, much like X- rays, and move at the speed of light.  They travel farther through air than alpha or beta particles and can be stopped by a thick shield of lead, steel, or concrete.
• Natural radiation is found in soil and in the food we eat.  Radiation also reaches us as cosmic radiation from outer space. Finally, many common medical procedures, such as chest or dental X-rays, expose us to radiation.  Further information regarding radiation may be found in the brochure.