for Shots 4 and 5, this barge was 62,200 tcet from the
shot barge for each of these shots. For Shot 6, the
bolometer was mounted on a power house un Yvonne
Istand, 77,522 feet from the shot barge.
The modulated bolometer consisted! of two black-
Mountain Laboratory, and the terrestrial backup
ground photography was made by EG&G in conjunction
with Project 13.2.
Analysis and reporting of the data were the responsibility of EG&G. One RB-36 and three C-54 aircraft
participated in the aerial photography and flew a total
of six missions per aircraft.
ened platinum wires whose resistance changed with
temperature.
Usable results were
One wire was in cuch ¢f two arms of a
obtained from two or more aircraft on all events ex-
Wheatstone bridge, which with a mechanically driven
cept for Shot 3, where photo results were negative
chopper alternately exposed first onc wire and then
due to natural cloud cover obscuring ground zero.
Preliminary analysis of the Castle cloud data indicated
the other wire to the thermal radiation. The application of a de voltage at one end of the bridge resulted
exccllent results for the period of H + 10 minutes.
Aerial oblique photography supporting Project 3.2,
in an ac output at the other end that was ampliticd
and recorded on magnetic tape.
Crater Survey, was flown by Lookout Mountain Laboratory personnel. This mission consisted of a
serics of acrial photographs tracking an LCU during
the period of time fathometer readings were being
Total tuermal energy was measured by use of
Epply thermopiles faced toward the detonation site.
The output of tne thermor!ics was recorded on Brown
recording potentiometers. These thermopiles were
made in the Shot 1 crater.
located on Tare, How, and George Islands for Shots
flown on Shots 1 and 3 by Strategic Air Command
barge near How Island for Shots 4 and 5; for Shot 6,
they were located on Fred and Yvonne I{slands.
Preshot and postshot crater vertical acrials were
reconnaissance personnel.
iand 2.
Analysis of the crater
dimensions was made from this photography by the
Army Map Service for Project 3.2.
Technical still photography requirements in support
of DOD projects were met entirely by Los Alamos
Scientific Laboratory photographic personnel. All
They were located on Nan Island and on 2
Project 18.3 “High-Resolution Spectroscopy”
(W'T-350), Naval Research Laboratory, H Stewart,
Project Officer.
For Shots 1, 2, 4, and 5, spectrographs of various
dispersions and in selected wave-lengih ranges werc
located in a concrete bunker at the hase of a 200-fovtower on the gouth end of Nan Island
Mbrrors on the
project requirements were coordinated and program-
med through Program %, including preshot and postshot photography.
tower re‘lected light from the detonations «» the viewing slits of the spectrographs.
PROGRAM 18: THERMAL RADIATION
MEASUREMENTS!
For Shot 6, spectro-
graph installations were established on Fred and
Janet Istands.
Project 18.2, Project 18.5 “Thermal Radiation”
Project 18.4 “Atmospheric Transmission of Light”
Naval Research Laboratory; H. Stewart, Project
Officer.
Naval Research Laboratory; H. Stewart, Project
Officer.
Atmospheric trangmissicn was measured over
Power-versus-time mcasurements were made by
employment of modulated bolometers.
These bolom-
ed on photo towers on How and Tare Islands for Shots
selected paths. To make these measurements, a
searchlight of known luminous intensity was mounted
1 and 2. The How tower was 97,975 feet and the Tare
tower 77,765 feet from ground zero of these shots.
near each zero site for cach selected path and trained
on a photocell receiver at the other end of the path.
The bolometers were mounted on a barge near How
The searchlight beam was modulated by a mechanical
chopper (60 cps) and the receiver system was ar-
eters were located in 8-by-2-by-8-foot coffins mount-
'Not a formal DOD program.
These thermal-radiation
projects of DOD interest were sponsored by LASL
(see Chapter 8). Publication information for Projects
18.2, 18.5, and 18.4 is as yet uncertain; information
on their availability and the availability of the Project 18.3 final (WT) report maybe obtained from
LASL.
ranged s0 that only light at this modulated frequency
was received, thus making the system independent of
daylight.
The paths for each shot were: Shot 1, from
zero site to George, Tare, and Deita Islands (Delta
is an artificial island near Able); Shot 2, from zero
site to George and Tare Islands; Shots 4 and 5, from
zero site to How and Nan Islands; and Shot 6, from
zero site to Fred and JanetIslands.
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