the surface to 20,000 feet
(6.10 km), for each 5,000-foot
ment from 20,000 to 70,000 feet
and 90,000-foot
(1.52-4km)
incre=-
(6.10 to 21.30 km), and for the [80,000-
(24.40- and 27.40—-km)
levels.
Radex Areas
Radiological exclusion
fice.
(radex)
areas were determined by the
These were usually defined as locations where significan
could occur within 6 hours after detonation.
adsafe Offallout
The plots were delfineated by
50-R (10-R for some shots) contours based upon the predicted inffinite dose.*
The radex areas were used to define dangerous areas and to deny
ntry to
task force units into certain areas except by specific authoriz
ion.
The surface radex area was constructed using the basic fore
st hodo-
graph limiting bearings of resultant winds to all significant lefels.
An
additional 15° sector was added to each side of these limiting bBarings
to allow for diffusion, changes in the forecast wind pattern, an
tion from a point-source origin of fallout.
sisted of two sectors.
Usually, the radex
deviarea
con-
One defined the low-level trade wind porfion of
the cloud, and the other defined the midlevels.
For all surface] radex
areas, the radial distance of the sectors was taken as that aver ge distance representing 6 hours of particle fall at 5,000 ft/hr
(1.52 km/hr).
This established outer limits of surface contamination that cons dered the
fall of particles of all sizes during the 6-hour period.
The su fface ra-
dex was valid from H-hour to H+6 and revised as necessary when fprecast
winds changed.
The forecast air radex areas were constructed in two regions describ-
ing the volumes of contaminated air above 10,000 feet (3.05 km)
40,000 feet (12.20 km).
The first volume was needed for test an
nd above
service
aircraft operating in the shot area to assist them in avoiding cq ntaminated regions.
The second volume was primarily for use in cloud; sampling
* The infinite dose is the dose from external sources that a per on would
receive by remaining within fallout contamination until it nat rally
decayed (that is, infinitely long).
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