NDL-TR-4
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THE CONTRIBUTION OF SCATTERED RADIATION TO IMMEDIATE
THERMAL CASUALTIES IN OPEN FOXHOLES.
J. J. Mahoney, April 1961.
CONFIDENTIAL
. S
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Personnel in open foxholes are partly protected against the
zards of thermal, neutron, and gamma radiations and blast ftom nuclear
detonations.
A study was made of current data in order to develop a
method for predicting the distances at which troops in open foxholes may
be expected to become immediate casualties due to these hazards.
In
particular, calculations were made in order to predict the distances at
which immediate casualties, due to thermal radiation, would occur where
neither the initial nuclear radiation nor overpressure are sufficient to
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SarPrg caleulat ions were made for the cases of Heights of Burst
equal to 25Cw+/3 ana 650wl/3 feet, where Wis in kilotons.
It was assumed
in the sample calculations that the thermal radiation at certain representative
points in the "shaded" portion of the foxhole was equal to 9% of the aboveground thermal radiant exposure. Further, this 9% was assumed to be made
up of two parts, 5% diffusely reflected from the foxhole walls and the
remaining 4% which entered the foxhole as atmospherically scattered radiation.
These assured percentages are based on previously published experimental
works.
Seperate consideration for fission and thermonuclear types of
bombs was recessary due to difference in character of the initial nuclear
radiation in these two cases.
work:
Tre following conclusions were reached as a result of this
1.
The general formula for thermal radiation entering a foxhole,
as used in the UPSHOT-KNOTHOLE work, was modified to take account of air
scattered radiation.
2.
For air burst bombs of yields greater than about 7O KT
immediate thermal casualties are produced for troops in open foxholes at
significant distances, calculated using available experimental data, for
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which the initial nuclear radiation and overpressure hazards are only
nominal or negligible.
3.
Contrary to previous doctrine, the thermal radiation which
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enters a foxhole as & result of atmospheric scattering is significant and
should be considered in estimating casualties.
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