A comparison of the LCT-332 (5,700 feet, bearing 089° T from surface zero) reco-d with that from the CR 4.0 shows that the first peak dose rates were at 0.9 minute and at 1.0 minute, respectively. The peak dose rates for the two shots appear, on the basis of this limited data, to be about the Same order of magnitude; however, the total dose registered by film packs on the weather decks of the target ships for Baker are one or two orders of magni- tude larger than total doses registered at similar locations for Umbrella (References 7 and 101). A detailed description of the film packs employed for Baker has not been located; however, it is probable that they were packets of Eastman Kodabromide G-3 and Eastman 548-0 double and Single coat film shielded with a lead cross approximately 1 mm thick. Although the increased Sensitivity of this type of film pack to beta and soft gamma radiation and the effects of heat prior to recovery may have tncreased the recorded total dose, neither effect could cause the large differences observed. It appears, therefore, that a very much heavier deposition of radioactive material occurred during Baker. The large deposit dose from Baker is thought to be due to fallout from the cumuliform cloud, which contained large amounts of radioactive coral from the lagoon bottom. Bottom material, however, does not appear to have been important during Um- brella even though this shot was fired on the bottom. A satisfactory explanation of this difference between Baker and Umbrella has not yet been advanced; however, it should be noted that the column was observed to vent to the atmosphere on the former shot, while no such observation exists for the latter. 3.3.5 Estimated Waterborne Radioactivity. The contribution to the free-field gamma dose rate from radioactive material falling inte the ocean is negligibly small in comparisonto the other radiation sources. Since only small amounts of radioactive material appear to have fallen from the base surge at distances greater than 3,500 feet (assumed maximum distance of heavy rain, see Section 3.3.1), the relative insignificance of radiation due to material suspended in the * water is not surprising. This statement, however, is definitely not true of the other sources of waterborne activity discussed later in this section. The relative unimportance of radioactive material deposited from the base surge and remaining suspended in the surface waters is indicated intwo ways. First, in all instances where the gamma record is not complicated by other waterborne sources, the underwater gamma records drop abruptly after registering passage of the airborne material, without showing any appreciable residual radiation. Second, FFP’s dropped into the downwind array after the event do not register any dose significantly above the background. These FFP’s were dropped 120 minutes after Wahoo and 60 minutes after Umbrella; therefore, the film pack data certainly indicates that no significant contribution for suspended material exists after these times. This data cannot be considered conclusive, since if all suspended material is assumed to sink at a rate of 0.96 m/hr (discussed later in this section), the postshot FFP drops are too late to register any significant dose from suspended material. The data dose imply either that the dose from suspended material remaining near the surface is inSignificant or that, because of the sinking rate of this material, all important radiation ceases Shortly after passage of the base surge (for the stated sinking rate, this time would be approxiMately 30 mimites}. Table 3.21. The doses obtained from these postshot FFP drops are summarized in Records from the underwater GITR (UW-GITR), described in Section 2.2.2, are subject to the same Mmitations set forth in Section 3.1. Unfortunately, a great deal of difficulty was ex- Perienced with the underwater detector cables and with the probe-dropping mechanism; therefore, only seven underwater records were obtained for Shot Wahoo and four for Shot Umbrella (Figures 3.143 through 3.153). The majority of the underwater records show a high dose rate peak at a time roughly corresponding to the peak registered by the std-GITR upon passage of the airborne radioactive material (compare Tables 3.8 and 3.22). The fact that the underwater detectors frequently produce records similar to those of the std-GITR leads to the suspicion that these detectors were much closer to the surface than the planned 6 feet. — Accordingly, tn all cases where both a standard and an underwater record exists, the two records are compared. Since peak dose rates do not provide a reliable basis for comparison, 244 Pages 245 and 246 were deleted.