TABLE 4.] ACTIVITY PER UNIT AREA FOR SKIFF STATIONS, SHOT CHEROKEE No fallout was collected on the skiffs omitted from the table. Station TABLE 4.2 I. fissions/f2 AA BB cc DD 3,094 3,094 4,459 9,885 196.6 196.6 150.3 214.2 2.5 2.5 2.8 8.7 x 10" x 104 x 10 x 104 GG HH MM vv 5,720 858 8,783 452 196.2 196.1 214.0 432.0 4.6 6.9 7.7 8.0 x x x x 10% 10° 10 10° EVALUATION OF MEASUREMENT AND DATA RELIABILITY Instrument Measurement Station location, ships Station location, skiffs Time of arrival —_ A A-C A-C Time of arrival 1c A-D Time of arrival TOAD A Time of peak ionization rate Time of peak fallout arrival rate Ic D Time of cessation TR B-D Time of cessation Ic c Tonization rate, in situ TR A-C Approximate Field Measurements and Deposition Properties Class A Dip counts/min at H + br _ TIR TIR Comments £500 to 1,000 yards. +1,000 yards. Arbitrary selection of significant increase above background. Uncertainty in first tray significantly above background; arrival uncertain within time interval tray exposed. Uncertain for initially low rates of field increase; malfunctions on skiffs; clockreading difficulties. _ Uncertain for protracted fallout duration and sharp deposition rate peaks. Depends on knowledge of decay rate of residual material. Rate plot for protracted fallout and fallout with sharp deposition-rate peaks may continue to end of exposure period; cumulative activity slope approaches 1. Poor directional-energy response (Appendix A.2); variations in calibration; poor inter- Cc c N B Apparent ionization rate, in ocean Apparent ionization rate, in tank lonization rate, above sea surface Tonization rate, in situ SIO-P SsIO-D NYO-M TB, Cutie Pie c N D Total dose Total dose Weight of fallout/area TR ESL film pack occ D Fraction of device/area (Fe, U) . , occ D Original coral-sea-water constituents occ c Fissions and fraction of occ D Fiasions /area SIO-P, dip device/area (Mo™) chamber agreement. Calibration variable, mechanical difficulties. Calibration variable, electrical difficulties. High self-contamination observed. Calibration for point source in calibration direction; readings ~ 20 percent low above extended source. See above: Ionization rate, TIR. Assumed + 20 percent. Bias uncertainty (Section 4.3.2); variability of background collections; see below: Elemental composition, fallout. Bias uncertainty(Section 4.3.2); uncertainty of indicator abundance in device surround- ings; see below: Elemental composition, fallout. Variations in atoll, reef, and lagoon bottom composition; see below: Elemental composition, fallout. Bias uncertainty (Section 4.3.2); device fission yield uncertainty. Uncertainties in dip to fission conversion factor, ocean backgrounds, fractionation of radionuclides, motion of water; see above: Apparent ionization rate, in ocean.