64 MILLER AND SARTOR I, at each station contributed by each particle-size group was calcu- lated from activity measurements on sieved fractions of the fallout samples. The constructed fallout patterns for several of the particlesize ranges and for the total fallout pattern are shownin Figs. 5 to 8. The activity—size distribution derived from this analysis is shown in Fig. 9. The median particle diameter for the distribution is 210 u. The derived distribution is not lognormal. The f, values from which the distribution was determined are summarized in Table 9; also given in the table are the f,r, and f,K), values leading to the estimates of Tf and K, for the whole fallout pattern. The sum of the intensity—area integrals, Jp, of the fallout patterns for the different particle groups is 580 r/hr at 1 hr per square mile; the value of J, for the pattern of the gross I, contours is 640 r/hr at 1 hr per square mile, about 11% larger. Theyield of the Small Boy shot has not been reported, except that the yield was small.? With the use of the intensity—area integral for the I, contours and the yield, the value of Jp/BW for the pattern thus could be estimated, With a Ky value of 1070 r/hr at 1 hr per kiloton per square mile, the value of C could be estimated; and the fraction of device, F,, accounted for within the estimated. The constructed fallout pattern of Fig. fallout patterns 8 could similarly be constructed for the various particle-size fractions do not include contributions from the regions of high I, values near ground zero nor from the large area of low-level fallout that was deposited in northern Utah. These contributions are not included in the analysis because fallout samples for determining the distribution of radioactivity among the fallout particles deposited in these regions were not available for analysis. For the total fallout pattern, including the contributions to I, from these areas, a Jp value of 1460 r/hr per square mile is obtained; this valueis a factor of about 2.3 larger than that calculated for the fallout pattern constructed from the I, values at the stations for which particle-size data are available. The fraction of the device, Fp, accounted for within the larger fallout pattern, would therefore be 2.3 times that for the smaller pattern mentioned earlier. The ratio of the contributions to the intensity—area integral for the high-intensity region to the lowintensity region, as determined from integrals, is about 3 tol. If an average r, value of 0.29 is assumed for thefallout in the highintensity region and an average r_ value of 1.5 for the low-intensity region, a value of K, can be estimated for the larger pattern from the data of Table 9, Allocation of appropriate fractions of the intensity— area integral to the three areas gives a weighted average value for Ky of 1400 r/hr at 1 hr per kiloton per square mile; the corresponding