Military Application
.
ed
ose
At ten to fifteen seconds efter shot time, a dense black
cloud began iseuing from the ground zero area. This black
fifty seconds until the underground cavity collapsed. At
H plus 2 minutes, the maximum telemetry reading at 300 feet
from ground zero was greater then 1,000 roentgens per hour
with a reprezentative deciine occurring down to a reading of
0.50 r/hr at E plee 28 hours.
Following the initiel release, the radioactive air mass rose
to about 10,500 feet mean sea level (MSL) end moved to the
southeast toward Cactus Springs and Indian Springs, Nev.
The highest recorded reading st any populated off-site
locality was Cactus Springs, Nev. (about 34 miles from ground
zero) where ground monitors reccrded 6.0 milliroentgens per
hour at zbout two houre after the detonation. The radiation
levels essentially returned to tackground values the following
day.
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DOE ARCHIVES
Late on March 13, the leeding edge of this redioactive air
mass wes shout 25 miles east of Needles, Calif., and extended
to the weet stout 50 miles.
ctivity wes detectable only
bstween 7,000 and 10,000 tect MSL and no ectivity was detected
below 4,000 feet MSL. Near Blythe, Talif., the radioactive
ait mass started co bresk up ints serail pockets. From that
point south towarc Yums, Ariz., tne clou2 wee discontinuous
end pecketse were decsiztad only et altitudes between 2,600 and
7,000 M5, Irom Serurday “Merch. Lf afcernson on, all tracking aircrafc reported intornation to the effect chat the
radioactive eiz mess had dispereed to the point of being no
longer detectable, Suheequently, the Air Force concentrated
its efforts on checking etr masses
coring out of Mexico to
determine the existence of radioactive detris with negative
:
results,
III - 56
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effluent continued to epew cut of the ground for about
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