Chapter 3 RESULTS AND DISCUSSION 3.1 GENERAL DESCRIPTION OF THE DATA In any consideration of the resuits presented in this and following chapters, a number of points should be borne in mind. Because of the nature of weapon-effect tests, investigations in the field must be conducted for single shots fired at a time that may not be convenientto the individual project. This condition is not conducive to precise work, particularly in situations requiring the maintenance of numerous stations over large areas of deep water, a situation peculiar to this project. These difficulties were further augmented by the fact that little concrete information on the complex gamma fields associated with underwater nuclear detonations existed during the planning and operative stages of the project. Nevertheless, the data obtained and reported here, when taken as a whole, exhibits a degree of internal consistency that is surprising considering the conditions under which it was collected. This consistency suggests greater reliability than that indicated by the stated limits of accuracy that were established on the basis of maximum possible experimental error. Since, however, so little is currently known about gamma fields associated with underwater nuclear detonations, some data that might otherwise have been omitted has been purposely included. To interpret such data, the treatment has in some instances been carried beyond that warranted by statistical reliability. Special corrections have been applied, and certain portions . have been emphasized on the basis of an intimate knowledge of conditions existing in the field. This extended treatment is based on the assumption that an estimate by persons completely familiar with the project is better than no information whatever. In all such cases, the uncertainties and assumptions are fully stated in the body of the report. The unmodified data is presented in Appendix D. It should be reiterated that in most instances the data contained in this report is considered sufficient and presents a consistent and logical picture of both shots. All materia! contained. in this report was obtained at fixed locations within the specific radiological environments g* erated by the two underwater nuclear detonations documented; therefore, its extension to other devices and particularly to moving objects must be performed with Special caution. During Shot Wahoo, the project recovered an estimated 60 percent of the maximum possible coracle data. This genera) index of success was arrived at by weighting each instrument according to the relative importance of the data it obtained. Using the same arbitrary system of evaluation, the project also recovered about 60 percent of the maximum possible data from the target ships. These low figures are primarily due to the accidental firing of all coracles on D—1 day, to the limited number of FFP’s recovered, and to a power failure on the DD-474 and DD-592 prior to the shot—all of which were beyond project control. Nine out of the 12 critical Stations re-armed the night of D-—1 showed a high percentage of proper instrument operation, thus, a fairly complete gamma-field history can be reconstructed with the help of photographic data. Although essentially no significant data was recovered from FFP’s on this shot, the project at least demonstrated that it was operationally feasible to obtain Supplementary data in this manner. All correlation between free-field radiation and that occurring aboard ships must be based on the EC-2 and DD-593 records supported by film pack information from the DD-474 and DD-592. An eStimated 80 percent of the maximum possible data from the coracle and FFP array was recovered during Shot Umbrella. Although some project instrumentation aboard the DD-474 76