dilution of radioactive fallout material in the ocean and Bikini Lagoon. The difficult job of deep-mooring 14 to 17 skiffs in the open ocean to the north of Bikini Atoll was accomplished. The skiff stations were used for fallout collection. . Collecting stations were instrumented on islands of Bikini Atoll, two YFNB's and three rafts anchored in the lagoon, and on three manned ships. Samples collected and studied from early times with respect to gamma and beta activity were also analyzed for chemical and radiochemical composition, and determinations were made of certain of their physical properties, in- cluding distribution of particle size. -It is certain that this effort will pro- vide a basis for the improvement of theories describing the formation, dis- persion, and over-all characteristics of fallout. Four P2V-5 aircraft were used to survey gamma radiation from fallout- . contaminated ocean areas. The data were used to direct survey vessels and for determining contours in producing land~-equivalent fallout patterns. Fallout samples collected from a number of land stations were subjected to radiophysical and radiochemical measurements to determine better the characteristics of in-close fallout material. A gamma-rate meter sus-~ pended from a helicopter was successfully used to measure dose-rate contours. A few stations were. instrumented in an effort to evaluate the roll of the base surge in transport of radioactive material. Five B-57B aircraft were used to collect data on radiation dose and aircraft contamination resulting from early penetrations into the clouds and stems of thermonuclear detonations. Twenty-seven penetrations of radiation clouds from megaton-range detonations were made at tim from 20 to 78 min after detonation and at altitudes from 20,000 to 50,000 ft. The dose rate in the stem was found to be less than the dose rate in the cloud by a factor of 5 to 10. Important information for operational ng usage was obtained. Sufficient data on gamma exposure as a function of distance from the point of detonation of various high-yield devices were obtained go that it will eventually be possible to conclude dosage contours and the validity of scaling laws. ; ET oe te A reasonable picture of the initia] and the residual gamma intensities as a function of time after the detonation of high-yield devices should be obtained upon postoperational data analysis. Several types of building surfaces were exposed at various orientations to fallout on the bows of two of the collection ships. Contamination on all events waa so low that it was not possible to make good decontamination studies. Surfaces exposed to high fallout eldsSTi223 ended with very little contamination; however, 8 in itself may give data for the radiological recovery of military installations constructed from such - 30 - —-~