Fallout samples were collected from 2600 feet to 19,000 feet from ground zero in order to determine the mass per unit area, gamma activity per unit area, particle size distribution, and specific activity versus particle size of the fallout; to determine the gamma decay rate and spectra of the samples; to perform leaching and exchange studies on the radioactive debris; to measure the release of gaseous fission product iodine; and to determine the radiochemical composition of the fallout particulate. Twenty collectors (2 ft x 2 ft x 2 in. deep) were placed in the downwind sector at increasing distances. An iodine gas sampler was located approximately two miles downwind. The fallout was well distributed over the station array, and all collectors received significant deposits. Analysis of the debris was performed at the Nevada Test Site. Airborne iodine fission products were found in the contanainated field downwind from ground zero, and iodine fission products were fcund to volatilize or be otherwise released from particulate fallout. Gamma-decay measurements showed no evidence of radionuclide fractionation in debris from different locations, nor among different particle size fractions. Pulseheight distributions also indicated no significant fractionation of gamma-emitting radionuclides. A 4- pi ionization chamber decay rate …

The procedures and results of extensive pre- and postshot aerial photographic coverage by naval aircraft are described and evaluated. Objectives were to use highperformance photo aircraft to document pre- and postshot ground zero area conditions, to provide aerial photographs for immediate onsite use in operations, and to determine the unique advantages, if any, of this type of photographic coverage. One preshot and three postshot photo missions were run over the ground zero area by flights of two supersonic F8U-1P (Crusader) jet aircraft of the Pacific Fleet. During each mission black and white, infrared, and color films were exposed. Missions were initially limited to coverage of the immediate crater area but later expanded in area to include the extensive up-wind and cross-wind base surge deposition area. Results indicated that no particular advantage resulted from use of color and infrared film; black and white film proved quite adequate, at least for the low color-contrast area characteristic of the Nevada Test Site. Interim photointerpretation stereo techniques provided the initial gross crater measurements. More deliberate photogrammetric efforts were later employed to locate crater contours and vertical profiles, relative to the bottom of the crater. The strong correlation of the residual contamination and the highly …

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