skiff team for those on the skiffs, all of which were anchored outside of the lagoon. The samples collected by these teams were returned to the sample-recovery center on Site Nan and processed there for shipment to the sample-distribution center on Site Elmer. Laboratory operations were conducted on the YAG 40 and on Site Elmer. One six-man team worked onthe YAG 40 during fallout, making the measurements of the SIC tray samples described in Section 2.2.3, while a second three-man team remained on Site Elmer to make the measurements of the IC trays as soon as they arrived. Decay measurements and other studies begun on the ship were sometimes continued by the same persons on Site Elmer and later at NRDL. Eniwetok operations consisted of the administrative activities of the project headquarters office located there, and the sample-processing activities of the sample-distribution center. All samples collected by ship, laboratory, and Bikini operations were recorded, decontaminated, monitored, packed, and placed on one of two early flights to NRDL by the four-man team assigned to this center. Thus, all samples were collected either aboard the project ships or by one of the Bikini stations; all, however, were routed through the sample-distribution center on Site Elmer before being shipped to NRDL. Charts removed from recorders and recordsof field-instrument readings were also processed through the center. Only SIC and IC trays were used for fieldlaboratory measurements, all others being counted and analyzed at NRDL. 2.4.2 Technical. Fallout information was required in three broad categories: buildup char- acteristics, including all time-dependent data associated with fallout arrival; physical, chemical, and radiochemical characteristics, including both single particles and total samples; and radio- nuclide composition and radiation characteristics, including fractionation and gammaionization decay. The operational procedures discussed in the preceding paragraphs, as well as the instrumentation described in Section 2.2, were designed around these requirements. The rate of fallout arrival and most other buildup characteristics were determined from TIR records and measurements of IC and SIC trays. Consequently, this information was obtained at all major-sampling-array locations and several additional places aboard the project ships. Time of arrival, however, was determined at all stations; wherever major arrays were located, it was derived from the TIR’s and IC’s, while the TOAD’s supplied it for the minor arrays. The way in which particle-size distributions changed with time was determined by sizing and counting IC tray collections, and mass-arrival rates were calculated from the same data. Ocean-penetration rates were derived from the probe (SIO-P) measurements made on the YAG 39 and YAG 40. Periodic TIR readings from the ships and selected SIC tray data were also reported to the con- trol center during each shot and used for preliminary fallout analyses. The majority of single-particle studies were performed on particles collected by the SIC on the YAG 40, although particles from IC and OCC trays, as well as two unscheduled samples from the YFNB 29, were also used. The sizes and gammaactivities of all particles were measured, diameter being defined and used as an index of size for solid particles and NaCl content for slurry particles. Solid particles were also classified as to type and used for a numberof special studies, including decay and gamma-energy-spectra measurements and radiochemical analyses. The total“amount of fallout, and all other properties requiring a total collection, were deter- mined from OCC and AOC samples. Asindicated in Section 2.2.4, all OCC and AOC, trays, as well as all AOC, bottles after the material in the funnel and tube had been washed into them with a dilute acid, were shipped directly to NRDL and gamma-counted. Following this, OCC tray samples from each station were removed and analyzed for their chemical and radiochemical compositions, so that the surface densities of various fallout components and the total amount of activity deposited per unit area could be calculated. Aliquots were withdrawn from the OCC-sample solutions at NRDL and measuredin the 4-7 ionization chamber along with aliquots of AOC, and sea-water samples in order to relate the different kinds of gamma measurements. Other aliquots and undissolved fractions of the original sample were used for gamma spectra and beta- and gamma-decay measurements, with gamma decay being followed both on crystal counters and in the 4-7 ionization chamber. Samples 26