vehicles and foxholes were corrected for neutron and station-shielding effects.
Gamma dose versus distance, corrected toa relative air density of 0.9, is tabulated in Table
5 and plotted in Figure 12.
Gamma doses at all Project 4.2 stations are tabulated in Table 10
for the test-condition relative air density of 0.85.
The 10 r/hr isodose lines, as determined from field surveys, were roughly circular with
radii of 200 yards or less. There was no evidence of a downwind hot line. The minimum and
maximum distances that these curves extended from ground zero at various times are tabulated
in Table 9. Since field surveying had to be concluded by H+7 hours, only limited experimental
data was obtained on field decay. These data only suggest that the contamination decayed accordingto the fission-product law. Reference 13 contains all survey data obtained for this event.
DISCUSSION
*
Although the film badges were in all cases exposed for more than 1 minute, it is felt that the
data in Figure 12 represents initial gamma dose or a combination of initial dose and dose caused
by the passage of the low cloud. Some close-in stations for all three events were affected by
TABLE 6
EMMETT GAMMA DOSES
Time Interval
min
0 to 0.05
0 to 0.25
oto’
0 to 1
% to 1%
1to 2
14 to 24
59a, ga8 deg
r
Dose at Station
000 yd, 325 deg
r
3,200
3,500
4,100
2,700
390
280
700
450
580
89
120-
2to3
2%, to 34
3 to 4
3% to 44,
4 to 5
44, to sy
5 to 6
5.8
14
0
3.8
3.6
1.3
2.9
1.5
1.4
0
0
0
0
0
0
0
0
200 yd. 305 deg
r
360
.7 390
260
*
110
400 yd, 308 deg
r
19
79
54
11
0
5.3
0
0
0
0
0
0
0
0
0
0
0
0
0
o
0
1.8
0
* Defective film badge
.
residual fields.
;
_
.
the Hamilton and Humboldt low air bursts, the values
beyond100yardsapproximated straight lines. The best least-squaresfit for these lines was
calculated and extrapolated to.100.and-1,000- yards.
.
the open-
field results of Shots Hamilton andHimbdldt were adjusted to a I-tor.-yiéid for comparative purposes.
Predicted gamma doses were calculated from Equation 1 for.a 1-ton yield.
24
Gamma