hot 72 hype. The line along which the greatest deposition of radioactive material is experie for atomic clouds whose maximum height does not exceed 2,00U feet, this line nearly coincident with the track of the center of the radioactive cloud. _-al surge center, H: the presumed location of the base surge center at a specific tin determined simply by moving surface zero downwind in accordance with the official Task Force surface winds. Ic: ICB: identifier: Incremental collector, an instrument that makes a sequénce of passive fallout collections on small trays (see Section 2.2.4). Instrument control box, a switching and timing device ee controls coracleinstruments (see Section 2.2.7). A larger float used to aid in spotting and identifying floating film packs from tt air; also an alphabetic or numerical symbol designating instrument position at given station (see Section 2.2.5). . initial dose or dose rate: Dose or dose rate from radiation occurring shortly after zero time during the venting of the radioactive products. intensity: A term used for both source intensity and dose rate. tsodose contour: a boundary drawn for a specified time after a nuclear detonation, along whic the cumulative radiation dose to that time is presumed to be the same. ITR: Interim Test Report. LASL: Los Alamos Scientific Laboratory, Los Alamos, New Mexico. late decay curve: A decay curve presumed to be characteristic of radioactive material deposi later than 5 minutes, possibly from such sources as white water. LCM: A small amphibious attack craft capable of carrying vehicles and making landi LCU: LDs q: directly on beaches. A large amphibious attack craft capable of carrying several vehicles and a sm: crane, and capable of making landings directly on beaches. Lethal dose 50 percent. For a stated type of radiation, the dose which results M-boat: NBS: NOL: in 50-percent fatalities in a population of exposed organisms within a stated period of time after irradiation, usually 30 days. The alphabetic time zone designator for the EPG indicating the time zone 12 hours later than Greenwich Mean Time (GMT). An LCM. National Bureau of Standards, Washington, D.C. Naval Ordnance Laboratory, Silver Spring, Maryland. NRDL: U.S. Naval Radiological Defense Laboratory, San Francisco, California. M: oce: Open-close collector; a large tray that is opened to collect fallout and later closed (see Section 2.2.6). PDST: Pacific Daylight Saving Time. Seven hours earlier than Greenwich Mean Time (GMT). photo-: a prefix used to indicate that the parameter in question is photographically det: mined as distinguished from one that is determined on the basis of the dose ral records. photo-boundary: any of several base surge boundaries determined from aerial photographs. photographic surge center, X: the presumed location of the base surge center at a specific tir defined as the center of the circle that best fits the outer photo-boundaryof the primary surge at the time in question. This center is presumed to move in ac cordance with this photo-boundary up to the time of the last reliable boundary (3.5 minutes for Wahoo and 6 minutes for Umbrella) after which it moves in plume: R-value: accordance with the official Task Force surface winds. One of the several large masses of water thrown upward and outward radially by an underwater water explosion. _ The ratio of the observed amount of a given radionuclide to the amount expecte from thermal neutron fission of U"°5, calculated on the basis of some referenc radionuclide whose amount is also determined. When the reference radionucli la not specified, Mo*® is usually implied through common usage. 421