-
~~ UNCLASSIFIED
of the fall-out comes from the stem,
‘The information available fram the
fall-out of T/S tower shots is not sufficiently detailed for this type
ef analysis, but it appears that for lesser KT tower shots (10 ET) the
soil in the stem remains relatively inactiv;, and most of the fall-ent
comes from the sand mixed in with the mustreom of the cleud. ‘Therefore
dein
for T/S Test Operation the Py/Ps rat’. may be 2 or 3.
If the ratio of
Py/P, continues to decrease with decreasing scaled height then fer a
we i
surface shot a large percentage of the activity will be in the soil
within the stem rather than the seil in the mushreom.
Attention is
invited to the relative constancy of the P,/P, ratio for 0/K towr
shota,
This type of constancy tends to increase ene's confidence in
the fall-out picture indicated in this report and in the air readings
utilized to delineate the centaminated area,
During T/3 tower shots
approximately 15% of the total residual activity of the bemb fell out
within six hours over an area ef 5000 te 10,000 square miles, 5% coming
from the stem and 10% from the mushroom.
During the tower shots of 0/K
the average percentage fall-sut appears to be 20%, 15% coming from the
stem, 5% from the mashroem,
According to Reference #9, 50% of the
total activity of Trinity was deposited immediately dowmwind (23 XT,
shot from a 200 ft tewer).
However, it is not clear how complete the
study ef fall-out was during the Trinity explosion.
There is sexe
evidence that altheugh an attempt was made to delineate the fall-~ent
quite accurately some years after the Trinity explosion, the fall-out
pattern was not studied in teo great a detail on the day of the shot
is
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UNCL
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