BIOASSAY The determination of the concentration of materials, including radioactive materials, within the body by sampling and analyzing tissue or body fluids. BURST An explosion or detonation. CHAIN REACTION A reaction that stimulates its own repetition, usually referring to fission or fusion reactions. CLOUD SAMPLING The process of collecting samples of the cloud resulting from a nuclear detonation to determine the amount of airborne radioactivity, both particulate and gaseous, contained in the cloud. This was usually conducted by specially equipped aircraft. CLOUD STEM The visible column of debris (and possibly dust and water droplets) extending upward from the point of burst of a nuclear device. CLOUD TRACKING The process of using either radar or aircraft to monitor the drift of a cloud resulting from a nuclear detonation. CONTAMINATION, RADIOACTIVE The presence of unwanted radioactive material on or within areas, objects, or persons. CUMULATIVE DOSE The total dose resulting from repeated exposure to radiation. DECAY, RADIOACTIVE The spontaneous emission of radiation, generally alpha or beta particles, often accompanied by gamma rays. The radiation is emitted by an unstable isotope. Asa result of the emission, the radioactive isotope is converted into a different element that may or may not be radioactive. DECONTAMINATION The reduction in the effect of contaminating radioactive material or the removal of contaminating radioactive material from a structure, area, object, or person. DEVICE, NUCLEAR A nuclear explosive device, commonly referred to as an atomic or nuclear weapon, engineered to produce a detonation with some predetermined characteristics. DOSE See ABSORBED DOSE or DOSE EQUIVALENT. DOSE EQUIVALENT The absorbed dose expressed in terms of its biological effect. It is the product of the absorbed dose in rads multiplied by a quality factor and any modifying factors. The dose equivalent is expressed in rem. 204