tained by F-84 and B-36 aircraft penetrating the cloud
from each detonation. Air Weather Service WB~29
aircraft equipped with particulate and gas-sampling
devices collected samples at remcie distances from
the nuclear detonation.
Five F-84G aircraft utilized the method of snap
gas-sampling. This consisted of un exterior stainlesssteel probe in the nose of the aircraft that fed into a
deflated polyethelene bag. Samples were taken by
activating a valve andfilling the ;.olyethelene bag by
ram pressure.
Ten F-84G aircraft were eq.ipped with a dual elec~
to produce a response tu rate of change of pressure
down to very-low frequencies. £ sitivity was approximately 50 mm/ (dyne/em*)
an EsterlineAngus recorder operating at 0.7 .n/min.
The AFCRC operated modific T-21-B equipment
developed by NEL Tape speeds and sensitivities
were approximately the same as those used by NEL.
The Air Weather Service (AWS) operated crossed-
loop goniometers at distant stations to record azismuths. These were similar to their standard sferics
low-frequency (10-kc) narrow-band (about 0.5-kc)
direction-finding stations used for locating thunderstormareas as an aid to weather forecasting. The
AR
trical compressor system feeding into two 500-in*
operational stations had a slightly wider
bandwidth (8 to 12 ke).
Distant stations for the most part utilizedlocagions
a.ready in use by NBS, DRL, AWS, or A
Insofar as possible, sites were chosen on east-west
anc north-south orientations in an attempt to get
some idea of differences due to a daylight path, a
Castle provided the first full-scale operational test
of this system. In addition, several B-36 aircraft
were equipped with the squeegee system; for these,
the intake air was bied from the upstream side of the
large cabin pressurization filter and fed through com-
dark path, and auroral-zone transmission.
Somedistant stations were located in proximity to
stations transmitting low-frequency carriers.
In
order to avoid interference from these stations, their
cooperaticn was enlisted and they were shut down at
critical times.
Project 7.2 “Detection of Airborne Low-Frequency
Soundfrom Nuclear Explosions” (WT-931), A
G. 8. Olmsted, Project Officer.
Measurements of the airborne low-frequency sound
from the Castle detonations were made at fifteen re~
mcte locations at a variety of distances and directions
from the Eniwetok Proving Ground to study the relation between signal characteristics and the energy
released over a range of yields up to 15 Mt.
Beth standard and very-low-frequency soundrecording equipment responsive to smal! atmospheric pressure variations in the frequency range from
).00z to 1 cps were employed
Project 7.4 “Calibration Analysis ofClase-in
Atomic Device Debris” (WT-932), AFi
compression cylinders (3,000 psi). All of the air
sampled was bled from an intermediate stage of the
axial compressorof the aircraft and fed into the dual
compressors— the squeegee method. Operation
pressorsinto 900-in® (3,000 psi) cylinders.
Longer-tange sampics were obtained using WB-29
aircraft with associated C-1 foils for particulate
samples and a 8-31 gas-sampling device for gaseous
debris.
The collection of all close-in particulate samples
was under the technical direction of the Los Alamos
Scientific Laboratory (LASL); the collection of gas
samples was supervised by AFOAT-1.
The University
of California Radiation Laboratory (UCRL) was responsible for gas separation and analyses of some
samples at the test site.
Instrumentation, techniques, and procedures in
the processing, separation, and assay of the nuclear
particulate and gaseous debris are included in detailed
LASL and UCRL reports.
Close-in gas samples were collected at altitudes
in the range of 35,000 to 50,000 feet MSL. Gaseous
debris sample sizes collected varied from 107'5 to
107"' bomb fructions. Representative sections of
7D. L.
Northrop, Project Officer.
each test cloud were sampled, but due to extreme
The work of this project was a continuation of a
pregramcstablished to monitor all U. S. nuclear
detonations, in order to determine calibration reference points for the analysis of airborne nuclear
debris. These data were obtained by the application
of chemical, radiochemical, physical, and nuclear
analyses to the debris collected by specialized sampling devices. The calibration da:a were further cxanded by making similar measurements on nuclear
debris collected at great distances from the detona-
cloud heights obtained on high-yield detonations, only
the lower portions of these clouds were sampled.
Long-range samples were collected from approximately sea level to 20,000 feet.
PROGRAM 9: TECHNICAL PHOTOGRAPHY
Project 9.4 “Cloud Photography” (WT-933),
tion
Nuclear-debris samples close-in to the detonation
were obtained utilizing sampling devices on F-84,
WB-29, and B-26 aircraft. Similarly equipped WB-29
aircraft operated out of Hawaii for the long-range
calibration samples.
Close-in particulate and gaseous samples were ob-
117
Edgerton, Germeshausen and Grier, Inc.; JackG.
James, Lt Col, USAF, Project Officer.
Project 3.1 was established for the purpose of recording photographically cloud formation phenomena
that would satisfactorily supply data for use in study-
ing the aircraft delivery problem and correlation of
fallout studies in relation to cloud drift. The technical aerial photography was conducted by Lookout