the fission fraction.
To normalize to the 5-Mt detonation, dose rates are assix.od to incresse
with the cube-root scaling taw and the areas, following the sanie law, are increased by the square
of the cube root.
Figure 2.45 presents the results, after normalizing the Redwing surveys. The H+1 hour
dose rate in roentgens per hour is shown plotted against the area in square miles, enclosed by
the contour of that dose rate. For comparison, the predicted contour areas for a 5-Mt detona-
tion have also been indicated (Reference 8).
From this presentation, several things become apparent.
The area of the highest radiation level for Zuni (1,180 r/hr after normalizing) ts considerably
less than for Shots Navajo and Tewa. This is further evidence of the loss of fallout material
below the assumed mixing depth in the region close to ground zero, where high radiation levels
are to be expected. The dropoff of area at the lower dose rates for Zuni results from the fact
that these are only minimum areas, since the survey contour lines could not be completed.
The straight-line plot for Tewa indicates that although this was considered a land shot, the
thin film of water approximately 20 feet beneath the barge must have had a modifying effect on
the type and size of particles in the close-in region.
No attempt was made to estimate the con-
paiementcn nee ie ie
tour areas below 10 r/hr for Tewa.
The good agreement of Navajo with Tewa indicates that the errors introduced by the oceanic
background were indeed negligible. This agreement also lends credence to the assumption that
dose rate increases in direct proportion to the fractional fission yield.
31