As discussed in Section 3.1.2, the distribution of gamma energies was estimated from the

visual observations of a meter on the gamma spectrometer. Observations at 500 and 800 feet
above Site Sally on Mohawk D + 2 showed a general response where the predominant portion of
the energy spectrum fell between 350 and 600 kev.

3.3 DISTRIBUTION OF FALLOUT
The tsodose charts contalned In this section have been referred to B ¢ 24 bours and gamma
dose rate at 3 feet above the surface. The decay correction is based ont—*-{ The flight altitude
was 300 feet for all surveys, so the altitude correction is based on a factor of 2.5.

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Figure 3.5 Flight pattera, Shot Cherokee D-day.

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The EOB is based on a minimum detectable limit by the detector of 0.01 mr/br. This converts to 0.025 mr/br at the surface. Where there are no fight legs in a position to close an
isodose plot, dotted lines indicate the estimated position. The estimates are based on previous

days’ results wherever possible. Contamination enclosed within an isodose bounded area is

calculated on the basis of the average gamma intensity between consecutive isodose lines, and a

,

contamination density of 0.4 megacurie/naut mi’ for 1 mr/br of gamma dose rate (Section 1.3.1). 3.3.1 Shot Cherokee. The D-day flight encountered no radiation intensities above the detectable limit. The flight pattern is included to show the area searched (Figure 3.5). The D<¢1
flight was used for instrument check, because ao contamination was found on the previous day.
3.3.2 Shot Zunt. The D-day Might examined the region in the vicinity of the atoll (Figure
3.¢). Because there was not enough data to develop tsodose Plots, radiation profiles have been

plotted along the flight legs.

38

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