(4) Although the cloud tracking plan included 10,000-f0ct
aerial sweeps upswing of populated areas cashot day and lowelevel precision
aerial sweepe on shot day plus one, it was found desirable to make low-level
passee over the northern MARSHALL Islands on shot day, For this purfose,
WE=29 cloud trackers were divertdd to dverefly these islands at approximately
200 feet from about H plus 10 to H plus 12 hours fora gmeral estinste of the

existing conditions, Since majof fall-out could cecur within 10 to 12 heures
after shot tim, the data obtained by these Mlighte gave reasonable ati tine=
ly assurance £q operational decisions relative to the existence cf 4 teal

hasard at the atells involved.

“=

(5) Considerable progress was made by scientific projects.in

defining the fall-out pattern cver-water by sampling the water itself sod
by lowelevel aerial survey of the contamineted water using sensitive scin—

tilistion-type gums rate meters. The use of rift of bucyfall-out collec
tors to measure the overmall patter was generally unsuecessful, due to cperational difficulties ta locating the eollectcrs, and due to losses of collec
tors arising from failure to locate and from shot delays.

The new methods,

using a few rafts-or bucye to tie in actual sumerieal values of intensity
shows great. premise:in solving the mjor fall-out documentation problem for
future operations ithe: FPG.
ft.

-

Perecamel.

(1) The-shot phase of an operation of the magnitudes of CASTLE
requires at least two Radsafe trained officers, at the Task Porce level

preferably three, and at least three clerical assistants. A fulltime assistant Radsafé Officer available during the 2,-hour period immediately preceding
and immediately following each shot would have precluded the requirement for
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