ma ionization dose. The AOC, consisted of a 7-inch-diameter funnel, a 4-inch-diameter tube, and a 2-gallon bottle, all of polyethylene, with a thin layer of fiberglass honeycomb in the mouth of the funnel. Collected samples were used to determine the activity deposited per unit area. 2.2.3 Special Sampling Facilities. The YAG 40 carried a shielded laboratory (Figure 2.3), which could commence studies shortly after the arrival of the fallout. This laboratory was independently served by the special incremental collector (SIC) and an Esterline-Angus recorder which continuously recorded the radiation field measured by TIR’s located on the king-post platform and main deck. The SIC consisted of two modified IC’s, located side by side and capable of being operated independently. Upon completion of whatever sampling period was desired, trays from either instrument could be lowered directly into the laboratory by means of an enclosed elevator. Both the trays and their collecting surfaces were identical to those employed in the unmodified IC’s. The samples were used first for early-time studies, which featured work on single particles and gamma decay and measurements of energy spectra. tailed physical, chemical, and radiochemical analyses. Later, the samples were used for de- Both the YAG 39 and YAG 40 carried water-sampling equipment (Figure 2.3). The YAG 39 was equipped with a penetration probe, a decay tank with probe, a surface- monitoring device, and surface-sampling equipment. The YAG 40 was similarly equipped except that it had no decay tank with probe. The penetration probe (SIO-P), which was furnished by Project 2.62a, contained a multiple GM tube sensing element and a depth gage. It was supported on an outrigger projecting about 25 feet over the side of the ship at the bow and was raised and lowered by a winch operated from the secondary control room. Its output was automatically recorded on an X-Y recorder located inthe same room. The instrument was used during and after fallout to obtain successive vertical profiles of apparent miliroentgens per hour versus depth. The tank containing the decay probe (SIO-D) was located on the main deck of the YAG 39 and was, in effect, a large always-open total collector with a windshield similar to that on the standard platform secured to its upper edge. It was approximately 6 feet in diameter and 6%, feet deep. The probe was identical to the SIO-P described above. Except in the case of Shot Zuni, the sea water with which it was filled afresh before each event, was treated with nitric acid to retard plating out of the radioactivity and stirred continuously by a rotor located at the bottom of the tank. : The surface-monitoring device (NYO-M), which was provided by Project 2.64, contained a Plastic phosphor and photomultiplier sensing element. The instrument was mountedin a fixed PoSition at the end af the bow outnigger and its output was recorded automatically on an Esterline- Angus recorder located in the secondary control room of the ship. tected by a polyethylene bag. During fallout, it was pro- This was later removed while the device was operating. The Purpose of the device was to estimate the contribution of surface contamination to the total reading. The instrument was essentially unshielded, exhibiting a nonuniform 4-7 response. It was intended to measure the changing gamma-radiation field close above the surface of the ocean for Purposes of correlation with readings of similar instruments carried by the survey aircraft. The surface-sampling equipment consisted of a 5-gallon polyethylene bucket with a hand line and a numberof '4-gallon polyethylene bottles. This equipment was used to collect water sam- Ples after the cessation of fallout. A supplementary sampling facility was established on Site How near the tower of the major Sampling array (Figure 2.8). It consisted of twelve AOC,’s without liners or inserts (AOC,-B), each with an adjacent survey stake, 3 feet high. The trays were filled with earth and buried in Such a way that their collecting surfaces were flush with the ground. Every location marked with a stake was monitored with a hand survey meter at about 1-day intervals for 5 or 6 days after each event. Samples from the trays were used in assessing the collection bias of the major Sampling array by providing an absolute value of the number of fissions deposited per unit area. 21