EXPOSURE RATES CALCULATED FROM SOIL SAMPLE DATA 1188 127s 1, 386 1, 246 '. 286 nuclide ere not ill be &° Co +25 ch Clearing Experiment Area Total activity per em* 4200 pe 90 pe 600 pe Calculated from concentra- 240 ur/hr 19 wprf/hr 24 ur/hr tion in soil sample Inferred from field spectrum 52 wr/hr 6 uwr/hr 9 ur/hr Percentage of total exposure B4% 8% 6% 77% 9% 14% <.6 74 rate based on soil mmediate could ince ground athering out radiation analysis (see p. 11) Percentage of total exposure rate from field spectrometer and ionization chamber data Core activity (pc/gm) 10 feet north of center 30 feet north of center 74 251 3.4 26 2d from Long vals. 1 an sy of -buted st 3 ites ling a le, 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 Island. The exposure rate measured at the center of the area was essentially the same as before (59.6 wr/hr). Additional measurements were made around the edges return to Bikini wt: $ “egg NRE ™ Smee eg