EXPOSURE RATES CALCULATED FROM SOIL SAMPLE DATA 87 Gs °°Co +25 sb Clearing Experiment Area Total activity per em” 4200 pec 90 pe 600 pe Calculated from concentration in soil sample Inferred from field spectrum 240 uwr/hr 19 pr/hr 24 ur/hr 52 ur/hr 6 ur/hr 9 ur/hr Percentage of total exposure 84% 8% 6% 77% 9% 14% rate based on soil analysis (see p. 11) Percentage of total exposure rate from field spectrom-~ eter and ionization chamber data 74 251 OO 10 feet north of center 30 feet north of center WA Core activity (pc/gm) 74 26 The percentages of the total exposure rate due to each isotope were calculated as discussed in Section II (p. 11) and agree reasonably well with the field spectrometric data in contrast to the calculated exposure rates which are quite high, much higher than could be explained by the excess activity from 3 - 5 inches. The core data also given in the table illustrate the large local variation in the total activity which is probably the main reason for the high values for the calculated exposure rates. This cleared area was resurveyed two weeks later upon return to Bikini Island. The exposure rate measured at the center of the area was essentially the same as before (59.6 ux/hr). Additional measurements were made around the edges