CHAPTER 2
DIROUTTAY
In the spring of 195k, Operation Castle, s series of atomic
tests, wes conducted at the Atomic Energy Commission's Pacific
Proving Grounds in the Mershell Islands.
Again, as in other recent
test series (1, 2, 3), an extensive network of gummed cellulose
scetate file sampling stations wes established by the New York
Operations Office Health and Safety laboratory to monitor the
deposition of radioactive dust resulting from the detonations. For
the Castle tests, the gummed film network was expanded considerably
to inoluie a representative world-wide network of 122 stations
(Figures 1.1 and 1.2). The U, S, Weather Bureau operated 39 stations
in the continental United States and 1) at overseas locations; the
Air Weather Service operated 23 overseas stations, the State Depart-
ment 31, three were operated by the Navy and Coast Guard, and two by
the Atomic Bomb Casualty Commission. The Canadian Meteorological
Services cooperated by operating nine stations and the Canadian Atomic
Energy Commission one. All stations were scheduled to make two
simultaneous 22-hour collections starting at 1230 G.C.T. each day.
The mechanism of transvort of stomic debris and the representetiveness of gummed fils samies hsve been discussed in previous reports.
The only changes in technique involved in the present series of ©
observations concern the decay correction and the installation of snow
melting devices at certain northern stations.
.
The
ed gummed film stand for use in snowy climstes consisted
of 8 0.5 ft* plate warmed by a thermostatically-controlled electric
heating element. The melt water was allowed to run off the surface,
making the observations comarable to those of rainfall on 8 conventional gummed film stand.
To simplify the procedures used in correcting for decay and
assigning masured activity to particulsr bursts, a somewimt arbitrary
system of burst assignment was. used in those cases where the burst
responsible for the radioactive debris was uncertain,
All radio-
activity collected from Pacific Islands and from ships was assumed
to have come from the latest burst, activity elsewhere in the world,
from the burst prior to the latest. Where there were definite
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vty
In addition, single gummed film stands wre installed on mst
ships of the Military Sea Transport Service scheduled to be on routes
in tae Pacific Ocean. The ship collections were also made daily.