636
FERBER
-—~= SAMPLING TRACK
—_1______
0
10
20
STATUTE MILES
©
DATA POINT
Fig. 4—-Sampling track and radiation pattern in a nuclear cloud at
45,000ft. Values given are in milliroentgens per hour at H+ 3Y3hr.
tion. The cloud covered an area of 5200 square miles at the 45,000{t altitude.
The sampling track appears to have covered the cloud very well.
However, the pilot reported shine from higher portions of the cloud
during the last few minutes of sampling whenthe aircraft was outside
the visible cloud. The readings due to shine were about 100 mr/hr. It
is possible that a significant fraction of the in-cloud readings may also
have been due to shine from the upper portions of the cloud; therefore
the estimate of the amount of activity at 45,000 ft may be high,
COMPARISON WITH RADIOCHEMICAL RESULTS
The radiochemical analyses of the samples obtained on the three
extended sampling missions provide a check on the method of calculating the amount of debris present from the dose-rate readings in the
cloud. The total number of .fissions collected in each Sample has been
determined, ' based on the number of atoms of **Mo present corrected
for the fission yield of °*Mo for thermal fission of 7“°U. If the total
volume of air passing through the sampling tank and the average dose
rate along the sampling path are known, the fissions per sample can be
estimated by the same method that was used to estimate the fraction of