ABSTRACT
Soil samples were exposed to neutron radiation from Shot Cherokee to help establish
the importance of neutron-induced residual gamma radiation
_ After exposure and recovery, the samples had no detectable
activity because the slant range to the nearest sample was nearly 3.5 miles, due to
an error in bomb drop. After this failure, an experiment was designedin the field
for Shot Yuma in order that induced-activity data could be obtained for a soil other
than Nevada Test Site (NTS) soil. Samples of sodium, manganese, and coral sand
from Site Sally were exposed above and below the surface at a slant range of 120 yards.
At this same station, gamma dose rates were measured and neutron detectors were
exposed by Project 2.51.
The full-field gamma radiation measured was due to a combination of fission-product
and neutron-induced activities, the only important induced activity being due to Nain, Y)
Na, at 1.1, 3.4, and 10.9 hours after zero time, neutron-induced gamma radiation ac-
counted for 1.2, 1.1, and 0.8 r/hr of the measured 6.0, 2.2, and 1.2 r/hr.
These values
were found to be within 50 percent of neutron-induced dose rates predicted by the method
of Reference 4.