SECTION 2 2.1 QYPEOF INMPORMATION REQUIRED FOR EXPERIMENTAL. \ A most important consideration in the design of a reliable decon- tamination investigation is a precise definition of a contaminated system consisting of fallout debris anf a contaminated surface. In this report, past data are summarized and used to develop scaling relationships that may aid in estimating the composition and amount of fallout per unit surface area required to produce ea given ionization rate from fallout that would originate from the detonation of various types of weapons near the surface of land, water, or in a harbor. 2.2 BASIC UNITS AND GENERAL DEFINITION OF THE por/NY For the kinds of detonations mentioned, the fallout is produced from three general source materials: (1) the bomb products ar device products, (2) soil or solids, and (3) seawater or liquid. ‘The possi- bility of rain weter in the fallout from atmospheric sources, seavater from a base surge in undervater detonations, and extraneous dusts from wind or blast waves will not be considered. The overall composition of fallout which might be found at 4 given point in a fallout area fron shots on land or at sea can be given in terms of two quantities: (1) the mass contour ratio, M,., defined es the ratio of the mass per unit area to the radiation intensity in r/tr, and (2) the device contour ratio, FD,, defined as the ratio of the fraction of the device per unit area to the radiation intensity in r/pr. The mass contour ratio is anin- verse function or measure of the specific activity of the fallout material. ‘The fraction of device contour ratio is a measure of the dispersion of the device as well as a measure of the radiation dosage potential of the radioactive composition.