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 measurement showed excellent agreement with a computed decay rate. Measurements of mass and activity distributions indicate that the radionuclides are associated with the volume of the particle rather than with its surface area. Radiochemical data are presented, but extensive analysis was not attempted. (auth)
Summary: The on-site radiological support program for Project Sedan was established to assist in exclusion area control, to ninimize the radiation exposure of participating personnel and observers, and to prevent the spread of radioactive contamination.
From introduction: The purpose of this study was to map the geology of the (Sedan) crater shell and relate the information gained to shell configuration and cratering mechanics. Hopefully, the data presented will be of use in planning future nuclear cratering experiments.
One-hundred and forty-six ejecta measurement stations encircled ground zero at eight radial distances ranging from 373 to 1707 meters. The twenty-four sampling lines were spaced at fifteen-degree intervals. Data presented were recovered from stations located at radial distances of 640, 853, 1067, 1280, and 1707 meters. An attempt will be made to recover data at stations located closer to ground zero at a later time. Preliminary analysis of ejecta data indicates that areal density varies inversely as distance raised to the 3.64 power. Circumferential variation of areal density is about a factor of 30 at the 1707 meter radial distance, a factor of 10 at the 1280 meter radial distance, and a factor of 7 at the 853 meter radial distance. Cursory treatment is given to several related subjects, including outer limit of base surge dust deposit, volumetric ejecta densities, locations of natural missiles and impact craters, and the outer limit of ballistic debris. One case of missile damage to a reinforced concrete structure is documented. Raw data are included in the appendix. (auth)
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 visible up-wind and cross-wind base surge deposition area is demonstrated. The potential value of a naval aerial photography in such events is discussed within the context of recent technological advances. It is concluded that such naval aerial photographic coverage is of considerable value in the rapid assessment of the gross effects of such large scale nuclear excavation events. (auth)
The performance of pressure-pulse transducers in determining distances of installed gages from small H.E. detonations by measuring seismic wave travel times was evaluated. Because of the superiority of the system time resolution as compared with conventional geophysical exploration equipment, improved accuracy was anticipated as well as an opportunity to dry-run the installed system in the operational environment. Also, a requirement for seismic velocity measurements in situ was fulfilled. Travel time measurements used satellite-hole gage placements, 5-pound C-4 detonations near the planned location of the device in the device hole, and operational diagnostic facilities. The results verified the original premise of the suitability of Plowshare instrumentation to determine with superior accuracy installed gage distances from the small H.E. detonations. Agreement of within 1% between surveyed distances and calculated distances was obtained for the three gage locations reporting. Seismic velocities obtained fell between 3825 amd 3875 feet per second. Also, the experiment demonstrated the integrity of the Plowshare instrumentation system as installed. (auth)
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