MASS DISTRIBUTION MEASUREMENTS

Abstract : An array of 186 sheet-metal collector pads was placed in a concentric circular pattern about ground zero (GZ) of a near-surface nuclear explosion. The detonation, with a yield of approximately 0.5 kt, occurred at a depth of 58 cm in desert alluvium. After the shot, when residual radioactivity permitted, samples of ejecta and dust (throwout) deposited on these collectors were obtained, weighed, and analyzed for particle size. One hundred samples were thus recovered at distances ranging from 50 to 600 meters from GZ. In ballistic trajectories, large particles were found to have traveled the greatest distances; deposition of very fine particles on the outermost rings is postulated to have occurred at least partially as a result of the base surge. Mass (weight) distribution of throwout per unit area is tabulated and shown graphically as a function of radial distance from GZ, and comparisons with similar experiments are made. (Author)