Chapter 9: Glossary Of Terms - SE Radiation Alert Frisker Operation Manual

Chapter 9: Glossary of Common Terms
Background Radiation
Naturally occurring radiation is always present. It includes high energy gamma rays and particles from the sun
and outer space and alpha, beta, and gamma radiation emitted from elements in the earth.
CPM (counts per minute)
The unit of measurement usually used to measure alpha and beta radiation.
Ion
An atomic particle, atom, or molecule that has acquired an electrical charge, either positive or negative, by
gaining or losing electrons.
Ionization
The process by which neutral atoms of molecules are divided into pairs of oppositely charged particles known
as ions.
Ionizing Radiation
Radiation capable of producing ionization by breaking up atoms or molecules into charged particles called ions.
Radiation
The emission and propagation of energy through space or through matter in the form of particles or waves.
Radionuclide
The naturally occurring or artificially produced radioactive form of an element.
Decay
When an atom emits an alpha or beta particle or a gamma ray, it becomes a different type of atom. Radioactive
substances may go through several stages of decay before they change into a stable, or non-ionizing, form. For
example; U-238 has 14 different stages of decay before it stabilizes. An element may have several forms, or
isotopes. A radioactive isotope of an element may be called a radioisotope. However, the more correct term is
radionuclide.
Half-life
Each radionuclide has a characteristic half-life, which is the time required for half of a quantity of the material
to decay.
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