principal objective was to attempt to confirm phenom-
to carry out their missions in the event of transit
through contaminated fallout, (2) significant attenuation is afforded by ships structures, (3) decontamination procedures require further development, and
ena observed in the F2 layer during Shot Mike of Ivy,
both in the general vicinity and st a great distance
from the shots, in order to learn more about the
ionosphere and to help determine possible military
applications such as long-range detection. .
Two ionosphere recorders were operated in the
Marshall Islands by project personnel: one at Parry
Island, approximately 200 miles west of the Bikini
shots (23 miles from the shot at Eniwetok), and one
at Rongerik Atoll, approximately 150 miles east of
the Bikini shots (350 miles east of the shot at Eni-
(4) there is negligible hazard contributed by boiler
air, or ventilation systems with fans turned off.
Project 6.5 “Decontamination and Protection”
(WT-928), Chemical and Radiological Laboratories,
Army Chemical Center; J. G. Maloney, Project”
.
Officer.
The primary objectives were to: (1) determine the
‘relative contaminability and decontaminability of con-
wetok).
ventional building construction materials when exposed to the type of wet-contaminant fallout which
would be characteristic of nuclear detonations in
harbors, (2) ascertain the relative effectiveness of
various decontamination techniques, and (3) determine the need for pre-attack protection measures
At Guam and Okinawa (about 1,400 and 2,600 miles
from Bikini, respectively), ionosphere stations,
regularly operating as part of the world-wide system,
furnished special data to this project at times bearing 2 specified relationship to each shot time.
When oscillograms from the ionosphere recorders
are properly analyzed, they give data on the height
and critical frequency (a function of the maximum
ion density) of each observable ionospheric layer.
On Castle, frequent records (up to four per minute)
were obtained with these recorders following each
detonation, the timing program varying according
to the location and operational conditions. Throughout the operation, regular recordings were made
five times an hour to establish normal conditions for
comparison.
in reducing contaminability and/or facilitating decon-
tamination.
Fourteen 4-foot-square panels with different types
of outside construction surfaces were mounted on
both a drone, washdown-protected Liberty ship
(YAG~-39) and an unprotected drone Liberty ship
(YAG~-40) which were operated through the fallout
area following Shot 2. For Shot 4, an identical set
of panels was mounted on board the unprotected ship
(YAG~-40).
For Shot 6, another identical set of panels
was roounted on board a barge moored in the fallout
area.
A tremendous amountof absorption (and possibly
Subsequent to contamination, the panels were
removed to shore, monitored for contamination intensity, and then subjected to decontamination efforts
utilizing a variety of hosing and scrubbing techniques.
The salt water washdown appeared to be effective
in minimizing contamination of construction surfaces
under the conditions of Shet 2.
The contamination resulting from Shots 2 and4
&
was very tenacious in nature and was much more
difficult to remove than the contamination encountered
in Jangle.
A great difference existed among the construction
surfaces with regard to initial contamination levels.
and ease of removal; of the methods employed, the
hand-scrubbing technique was the most effective.
Under the conditions of those shots contaminating
the YAG's, vertical surfaces became generally more
highly contaminated than horizontal and sloped surfaces. this was probably caused by the horizontal
wind components across the deck.
Project 6.6 “Effects of Nuclear Detonation on the
Ionosphere” (WT-929), Evans Signal Laboratory,
Signal Corps Engineering Laboratories; Fred B.
Daniels, Project Officer.
Ionosphere recorders were operated both in the
scattering) followed all shots, particularly those of
higher yields, causing obscuration of the F2 layer
for several hours at the Rongerik station and longer
at the Parry island station. However, enough data
were obtained at Rongerik to indicate that for shots
of megaton yield range an effect occurred which was
similar to the rising-F2-layer phenomenon observed
after Shot Mike of Ivy. Variations were noted between resulta of one shot and another which may have
been due to different yields or different ionospheric
conditions.
The Parry Island operation, though hampered, resulted in a new hypothesis to explain the protracted
absorption that may prove significant. It suggests
that the absorption occurring at Parry Island several
hours after the shots at Bikini (200 miles to the east)
was a rest of copious ionization overhead, caused
by beta particles and radioactive particles carried
westward by winds at 60,000- to 120,000-foot levels.
Records from distant stations indicated that ionospheric disturbance resulted from megaton detonations at ranges up to 2,600 miles.
These disturbances
apparently propagated outward from their origin at a
velocity of 8 to 16 km/min.
Marshall Islands and at distant locations to study
PROGRAM 7: LONG RANGE DETECTION
PROGRAM
the effects of the test detonations on the ionosphere,
Particularly on the F2 layer (the highest portion of
the ionosphere, from about 200 km upwards). The
Project 7.1 “Electromagnetic Radiation Calibra-
115