WT-1678
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RESIDUAL RADIATION FROM A VERY-LOW-YIELD BURST (U).
Operation HARDTACK.
M. Morgenthau and M. Schumchyk, December 1960.
SECRET-RESTRICTED DATA
Surersedes ITR-1678).
Surveys were made
to determine the radiation intensities of contaminated areas
nce
resulting from a very-low-yield,
surface nuclear detonations,
The area
flux
prepared by substituting
‘soi
rom
e Nevada Test Site (NTS) for the Coral
soil within the expected crater volume and over areas that were expected
to contribute debris to the cloud.
the
, Dee
nation of a 30-degree sector
extending 3)
downwind from ground zero would have been necessary.
The
highest alpha air concentration was_less than 2 per cent of the 1-hour
emergency exposure of 2 X 107F ne /em®.
i
lton
lip and crater
xposure
res
om
The radiation intensities at the
ere above 10,000 r/hr at H + 26 minutes, a
level that would haVé necessitated avoidance of these areas by troops.
The fallout consisted of NTS soil and coral particles and the size
fractions ebove 420 microns contained most of the activity. However,
fused silicate particles in the 420-to 840-micron fraction contributed
95 per cent of the total activity, although they were only 9 per cent
of the total weight.
.
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BEST AVAILABLE COPY
mal
WIr-1679
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NEUTRON FLUX FROM VERY-LOW-YIELD BURSTS (U).
Operation HARDTACK.
D. L. Rigotti, J. W. Kinch, J. H. McNeilly, J. L. Tarbox,
N. Klein, P. A. Pankow, and T. R. Adams,
SECRET
ent
August 1960.
The objectives of these projects were to:
(1) measure neutron
flux and dcze vs ground range for very-low-yield nuclear devices;
(2) measure neutron, thermal, and gamma radiation up to an altitude of
1,500 ft; (=) provide dose measurements in support of a biomedical
project; ana (4) determine neutron flux and spectrum for induced-activity
rrine
nd
studies.
Tre threshold-detector technique was used to measure neutron
flux.
Wati:nal Bureau of Standards film badges were used to measure total
gamma dcse.
Chemical Warfare Laboratories thermistor calorimeters were
employed for thermal measurements,
an Aerocap balloon
was used tc support the instrument
line a
directly above ground zero.
For Bursts =amilton and Humboldt, in addition to the standard-foil systen,
a chemical-ccsimeter system was employed to measure neutron and
simultanecus yy
gamma dose
@sults indicate that the balloon
technique fcr instrument location is effective for free-air measurements.
ee nee ee a
at ground zero ay -: Eniwetok Proving Ground was