Chapter 3
RESULTS AND DISCUSSION
3.1 EFFECT OF THE DELAY BETWEEN SHOTS QUINCE AND FIG
_ The original plan was to make this fallout study during Shot Quince, 6 August 1958.
;
it was decided to use the same
instrumentation array to measure fallout from Shot Fig.
Shot Fig occurred 18 August at the same ground zero that was used for Quince.
During
the time between shots, the buoy collector array suffered extensive damage due to high
winds and heavy seas. Although replacement buoys were manufactured from available material at EPG, they were not as rugged as the originals, and by 18 August one-third of the
buoy stations were missing. In addition, three buoy clusters were reduced from six to three
collectors; the remaining two clusters had only a single buoy each.
3.2 FISSION PRODUCT SOURCE STRENGTH
Relating to the gamma source strength of fission products at the reference time of 1 hour
after zero time (H+1 hour), the following will be assumed: (1) For 1 kt of fission products,
‘the gamma source strength is 5.8 x 10% Mev/hr. (2) For uniform distribution of 1 kt of
fission products on an area of 1 mi?, a dose rate of 2,650 r/hr will be recorded by instruments at a height of 3 feet above the ground surface.
References 4 and 5 provide the basis for thése numbers and show that the well-known
tote? decay approximation may be expected to apply reasonably well for the time period of
1 minute to a few thousand hours after zero time. That is, during this time period, a dose
calculated from a measured dose rate and the t~':? decay approximation would be expected
to differ from the actual dose delivered by no more than 50 percent, provided fractionation
effects are not more important than estimated in Reference 5 and discounting the importance
of weathering or translocation of debris by wind erosion.
3.3 CLOUD DEVELOPMENT
The Speed Graphic camera on Yvonne was intended to be the primary instrumentation
for cloud dimension data. However, low cumulus clouds partially obscured the detonation
cloud from the Yvonne station, making it difficult to obtain complete measurementsafter
H+4 minutes. The Wilma station served to provide the bulk of data for cloud dimensions.
Figure 3.1 shows a schematic of cloud development drawn from observations taken on Wilma.
The double-puff shape was also observed on the surface detonation of Operation Jangle and
may be an expected feature for a surface burst cloud.
Dimensions for general features of the cloud are indicated in Figure 3.2 by Diameters
A, B, and C, and by Heights h,, hy, and hj.
Figures 3.3 and 3.4 show the values of these
39
--