constant except for a few cases which showsignificant increases at later times. These in creases in dose ratios at late times occur only for stations Which are among those listed in
Table 3.2 as being probably affected by ingress of contaminants into the Ships.
As compared to the ratios of dose shown in Figures 3.6 through 3.18, the ratios of dose rate
shown in Figures 3.19 through 3.36 show considerably more variation. This is to be expected
because, once most of the dose has already been received, relatively large instantaneous
changes in the dose rate mayhave little effect on the accumulated dose.
For many of the compartments listed in Table 3.2, the dose-rate ratios show significant
peaks during-the time period following the last major-peak dose rate for both shots and during
the time period between the two major-peak dose rates for Shot Umbrella. Most of the abovementioned effect is attributed to the presence of contaminants inside the ship. Other variations
in the dose-rate ratios for all compartments were probably due to changing remote-radiationsource geometries and possibly due to effects from contaminated water Surrounding the ships
during periods when radiation from other sources was low (see Figure 3.31 for dose-rate ratios
based upon the data from the underwater Station 15).
3.1.3 Film-Badge Data. Averages of the 24-hour gamma doses aboard the target ships are
shown in Table 3.3. Film-pack data from Project 2.3 (Reference 7) are included in the table.
The locations of the various compartments are shown in Figure 2.8. The locations and data
from individual film-badge stations are presented in Appendix C. In general. the Project 2.3
film-pack doses are significantly lower than the Project 2.1 film-badge doses for the weatherdeck areas. ThiS maybe due to differences in film, in processing control, and possibly in
calibration and read-out technique. Some of the Project 2.1 film-badge data from Shot Umbrella
for the DD 474 appears to be anomalously low when compared to the data for DD 592; the GITR
data indicates that the doses on DD 474 should be significantly higher than the doses on DD 592.
The data was rechecked and the badges were reexamined, but no reasons for the anomalies
could be determined.
For Shot Wahoo, most of the film-badge stations were exposed to doses in excess of 500 r
apoard DD 474, 200 r aboard DD 592, and 90 r aboard DD 593. For Shot Umbrella, the doses
vere lower although the ships were from 1,000 to 2,000 feet closer to surface zero; but DD 474
and DD 592 were still exposed to doses in excess of 200 r in many compartments, whereas
aboard DD 593 the doses in all compartments were less than 45 r.
Ratios of averaged gamma dose in various compartments to the averaged dose on the weather
decks of DD 592 and DD 593 are presented in Table 3.4.
Ratios for DD 474 are not presented,
because the average dose on the weather decks could not be determined for Shot Wahoo, and because the film-badge data for Shot Umbrella was considered to be unreliable. For each compartment, the several dose ratios are in very good agreement So that reliable averages could
be determined. The film-badge dose ratios range between 0.36 and 0.56 for compartments on
or above the main deck, 0.14 and 0.46 for nonmachinery compartments belowthe main deck,
0.11 and 0.20 for machinery spaces above the waterline, and 0.019 and 0.068 for machinery
spaces below the waterline. Note that the possible limitations of the GITR dose ratios that were
discussed in Section 3.1.2 should also apply to the film-badge dose ratios.
AS a rough indication of dose distribution, the doses observed in each athwartship, i.e.,
transverse, third of various compartments were averaged and presented in Tables 3.5 through
3.7. In wide compartments there was a tendency to have lower doses in the center, presumably
because of shielding afforded by the superstructure. Another indication of nonuniform dose distribution in some compartments is the location-bias factor presented in Table 3.1 and discussed
in Section 3.1.2.
The available comparisons of GITR and film-badge doses at the GITR stations are presented
in Table 3.8.
The ratios of GITR dose to fiim-badge dose range between 0.72 and 1.46 and have
an average value of 0.96 witn a standard deviation of 0.14.
Comparisons of GITR and film-badge
ratios of dose at GITR stations to average dose on the weather decks are presented in Table 3.9.
The ratios of GITR dose ratio to film~badge dose ratio range between 0.76 and 1.21 and have ar
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