CLOSE-IN FALLOUT

Abstract

Abstract The phenomenon of radioactive fallout from an atomic explosion is described, and a quantitative technique for determining the distribution of radioactive material on the ground is developed. The primary factors which must be considered are wind field, yield and height of burst, and particle-size distribution. Certain parameters which enter directly into a fallout determination are given quantitatively, such as the altitude and size of the atomic cloud (as a function of explosion yield and atmospheric stability) and particle fall-rates (as a function of altitude and particle size). Two hypothetical fallout patterns for a one-megaton explosion, computed on a high-speed digital computer are presented, showing the large effect which the wind has in determining the character of the fallout. The meteorological problems associated with a fallout prediction are discussed.