• daughter: an atom chemically different from the radioactive parent atom which changed to produce it.
• decay chain: a radioactive isotope and the series of radioactive daughters which are generated from it through a series of radioactive decays. Production of a non radioactive daughter terminates the chain. DNA (deoxyribonucleic acid): the genetic material controlling the maintenance and reproduction of the cell.
• electron volt: a unit of energy; 1 eV = 1.6x10^12 ergs = 1.6x10^19 Joules.
• equilibrium factor (F): The ratio of the number of working levels actually present to the number of working levels which would be present if the short-lived daughters were in equilibrium with the radon present.
• equivalent equilibrium concentration (EEC): That concentration of radon in equilibrium with its daughters which would produce the same number of working level as are actually present. The ratio of the EE to the actual radon concentration is equal to the equilibrium factor F.
• ERDA: U.S. Energy Research and Development Administration.