‘Sw wr c arennipanrer bPee Seyr L tte 0018933 by the device R~values convert them to fractions of the two nuclides in the fallout. Table 3.5 lists results obtained in this way based on the averaged composition for the fallout. Table DATA ON NUCLIDES IN FALLOUT R-Value(Average) Fraction Deposited sr%0 cst37 M07? sr7 ¢sl37 Koa 0.52 O.L4 0.98 0.66 0.48 Walnut 0.78 1.13 0.80 0.81 1.00 Oak 0.45 0.40 0.89 0.52 0.40 All the fallout samples from the land and reef shots ‘show depletion of both sr? and Cs!37 as compared to the detonation yields. earliest samples. This is most pronounced in the Material coming down at times later than 4 hours for the land shot, and 6 hours for the reef shot, is quite uniform in composition and exhibits - little evidence of fall rate-dependent fractionation. The 4-hour fallout from the water surface shot is depleted in both sr?? and C3137 | but the 10- and 13-hour semples show an enrichment. have nearly the same composition. The two latter senples The failure of the 6- and &-hour flight missions makes the data rather scanty in this case. These effects are brought out clearly by the numbers listed in Table 3.6. 3.1.3 Combined Cloud and Fallout Data. If alternative processes to fallout are not important, fission products with volatile predecessors can be as useful as gEeseous fission products for measuring the extent of fallout. Since it is incorrect to assume that the content of a volatile fission product in fallout is zero, the R