rower
UNCLASSIFIED
Source
Height above plane
Dose rate
—:
feet
Cobalt-60
Cesium-137
NDL-TR-3
(vu)
-
mr/hr/curie/sq ft
1
614,000
6
430,000
3
1
3
6
497,000
i
|
!
|
|
ii
!
169,000
138,000
118,000
GROUND PENETRATING RADIATION (LIP CONTRIBUTION) IN A FOXHOLE
FROM A FALLOUT FIELD SIMULATED BY COBALTOO,
M. J. Schumchyk and H. J. Tiller, December 1960.
.
UNCLASSIFIED
my
The purpose of this work was fo determine dose rates in a
foxhole due to gamma radiation contamination on the area adjoining the
foxhole (lip contribution) located in a residual fallout field.
A cobalt-60 gamma source was used to simulate the fallout field.
The dose rate versus depth in a foxhole, 4 ft in diameter and 4 ft in
depth, resuiting from lip contamination was measured with 1- and 10-mr
stray radiation chambers.
The lip contribution, i.e., the ground scattered dose rate from
radiation that penetrates any finite amount of earth, to the total
radiation received in a cylindrical foxhole, was calculated and compared
with the measured results.
Also calculated is the skyshine or air
scattered dcse rate obtained at different levels in the foxhole.
The conclusions established were:
1.
The dose rate contribution from the lip of a 4-ft-diameter
foxhole, located in an infinite contaminated field, averages 68% of the
total dose received in the foxhole for the case where the lip contribution
is measured and skyshine is calculated.
2.
In the case where both are calculated from theory, the dose
3.
Clearing an annulus 2 ft wide around the edge of the foxhole
rate average is 4% lower.
removes about 99% of the lip contribution; therefore, removing about 644
to 68% of the total radiation received in the foxhole.
UNCLASSIFIED
i