twice the dose of the surface burst. At greater distances this dose differential decreased until
the doses became very nearly equal at 1,000 yards.
The residual fields in the Hamilton and Humboldt ground-zero areas were much lower than
expected as the yields of these devices were much lower than expected. In both cases the contamination was apparently fission products from contaminated tower materials. No elongated
fallout pattern was observed although one survey team for each event hunted downwind fallout.
The alpha-contamination levels of Shot Hamilton, at 100 yards or more from ground zero, were
below 120 g/m? which is considered an insignificant hazard.
TABLE 8
The Hamilton ground-zero area
SHOT HAMILTON ALPHA-CONTAMINATION LEVELS, pg/m?
Slant
Alpha Contamination at Azimuths Shown, deg
Distance
yd
25
55
85
115
1445
175
205
235
265
295
325
355
100
200
62.4
20.5
116.6
112.0
15.0
1.6
2.2
0.5
1.8
0.8
1.9
0.9
72.4
0.9
2.6
6.5
23.0
19.5
24.0
0.4
27.4
0.9
66.7
0.7
300
2.4
91.44
14
0.4
0.02
0
0
1.6
2.9°-
1.8
1.6
1.6
400
0.9
30.9
0.5
0
—
_
0
1.9
3.6
1.0
2.2
0.5
500
2.4
29.2
0.4
_
—_
_—
0
2.5
3.8
1111
0.9
600
700
800
1.5
1.3
1.7
0.3
0
0
3.8
2.1
1.4
7.9
2.6
3.1
0.5
—
_-_
0.6
0.6
_
91
—_
1406
41
—
——
—
_-—
Ol
_—__
0.6
0.89
—
was visually observed to be strewn with tower debris, paraffin, etc. Since this debris probably
became embedded with fission products and alpha emitters, the absence of this debris (as would
be the case for a detonation in free air) would cause even lower ground-zero contamination levels.
Since the Emmett devices were not in the fallout area for Shot Fig, no data were obtained on
fallout arrival or decay. The activity detected for a few minutes at the closest stations was
probably crater shine.
CONCLUSIONS
The following conclusions are based on the results from Shots
TABLE 9
Time After
Detonation
min
Hamilton, and Humboldt
DISTANCE FROM GROUND ZERO TO 10 R/HR ISODOSE LINES,
SHOTS HAMILTON AND HUMBOLDT
Shot Hamilton
Minimum
Maximum
yd
yd
Shot Humboldt
Minimum
Maximum
yd
yd
10
40
90
140
205
15
30
75
120
180
30
15
65
85
150
60
5
55
30
100
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. For the same yield at distances up to 300 yards from detonation, an air burst will deliver
at least twice the initial gamma dose of a surface burst. At greater distances the difference between the doses received from the air burst and the surface burst decreases, and the doses become nearly equal at 1,000 yards. ,
3. Lethal doses (600 r) of initial gamma radiation are received at approximately 150 yards
from the point of detonation
Ja 7.8-ton low air burst
28