ABSTRACT
Project 2.9 participated in Shot Quince and Shot Fig with the following objectives: (1) to document the initial gamma dose versus ground range and (2) to measure the total gamma dose received at a point as a function of time, at distances of military interest, for a fractional-
kiloton nuclear surface burst.
:
Project 2.12b participated in Shot Hamilton and Shot Humboldt with the following objectives:
(1) to provide gamma-dose measurements in support of the biomedical Project 4.2 and (2) to
document the initial gamma dose versus ground range.
In addition, secondary objectives of this
project were to document residual radiation intensities and to determine the field gamma-decay
rate.
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These objectives were accomplished by measuring the dose with film badges which were exposed at various ranges and azimuths, observing the dose on the film badges of the incrementalgamma-dose recorders (Emmett devices), and by field surveys with portable instruments.
Project 4.2 was furnished gamma-dose information for their stations.
The following conclusions are based on the results from Shots Fig, Hamilton, and Humboldt
and apply to fractional-kiloton-yield devices tested:
1. Initial gamma doses in the 300 to 900 yard range may be extrapolated from TM 23-200
data with confidence, for surface bursts.
2. Anair burst will deliver at least twice the initial gamma dose of a surface burst for the
same yield, at distances up to 300 yards from detonation. .At greater distances the difference
between the doses received from the air burst and the surface burst decreases, and the doses
become nearly equal to 1,000 yards.
.
3. Lethal doses (600 r) of initial gamma radiation are received at approximately 150 yards
from the point of detonation
the 7.8-ton Humboldt low air
burst, while the delivery crews, in the open, would receive 15 r of initial gamma radiation at
ranges
575 yards respectively.
.
4. The observed variation of gamma dose with azimuth for the surface burst is probably
caused by the contribution of dose from the transient cloud.
5. The residual gammafields produced by low air bursts detonated on wooden towers are
very small, less than 200 yards radius after 15 minutes, for the 10 r/hr isodose line. This
field is due to fission-product radiation, probably from contaminated tower materials.
;
6. The alpha-contamination levels from low air bursts at distances greater than 100 yards
are considered to be an insignificant hazard.