SLIDE Ll Ratio of nuclide to total fallout activity. The ratio of 1297 activity to total fallout activity would help in determining if the archival soil analysis for radioiodine corresponded to other measured or hypothetical ratios. The surface~soil activity of each nuclide measured by Brauer was estimated for 0.5 days post detonation. This was the assumed time of cessation of fallout at Rongelap. The value for the nuclide activty per unit mass of soil at the cessation of fallout was estimated from the best fit of archival soil results. The value of the denominator used in the ratio was based on measured gross beta activity. Gross beta analysis was done on soil samples taken on March 8, 1954 (0C68) from Rongelap Atoll. Hypothetical nuclide activity relative to total, fission product activity was estimated from data on thermonuclear fission of U given by Crocker (Cr65). Total activity values given by Crocker do not account for chemical and physical deletion or enhancement of fission products, production of activation products or production of transuranics. Total acitivity per 10,000 fissions at 0.5 days was taken from Table 3 of Crocker's report (Cr65). Individual nuclide activities were calculated by Crocker's methods and the original inupt data (Cr63). The ratio derived from BRAVO fallout measurements was based on Bikini Ash activity. For iE er 1295p) phe ratios were not similar however sample size was small. Eu and Cs, results were in accord at both Rongelap and Utirik. archival soil results for I at Rongelap and Utirik were distinctly different from the thermonuclear fission results and Bikini Ash results. The . SURFACE ACTIVITY RATIOS 0.5 DAYS POST DETONATION Archival Soil BRAVO Fallout Measurements Thermonuclear Fission “*U Nuclide Activity Nuclide Activity Nuclide Activity Gross Beta Activity Bikini Ash Beta Activity Fission Product Activity Measurements Nuclide 125 Sb al acs Eu 1.8X10 -7 6 Hypothetical 2.6X10_9 4.5X10 3.5X10--? 8.310 7T.1X10 9.6X10 7.6X10"° 7.1X10-4 16 4.610 -6 3.5X10 5.5X10-°