52

MILLER AND SARTOR

in the crater and crater lip would not be includedin the pattern summations. The intensity—area integral is defined mathematically by

Jp= J I,da
R

= f KA; da

(4)
(5)

R

where da is the incremental area, dx dy, and R is the region within the

lowest I, contour included in the integral. If K, is designated as the

weighted average value of the K,’s and C asthe ratio of intensity area

for the region R to the integral for the region enclosed by the contour
of I, equal to zero, then J,p can be represented by

Jp = CK,BW

(6)

where W is the total weapon yield and is the fraction of the total

yield due to fission. If the Ky value for the unfractionated mixture of
radionuclides produced in the detonation is designated as Kp (rs, = 1,
r,;= 1), then the fraction of the device deposited in the region, R, is
given by

Jp /BW
Fi = “Ki

(7)

p, = OKs

(8)

or

Kp

If K, is written in the form of Eq. 3, then Eq. 8 becomes
F

pk, + Ky]

In Eq. 9 the two bracketed terms refer to the intensities over an ideal
smooth plane on the assumption that the product Dq for K, is equal to

Dq for Kj.

The values of CK, and F, for a fallout pattern can be estimated
from the intensity—area integral and the values of Ky, k;, D, and q or
q. The value of C can be estimated if K, is evaluated separately, and Ky

can be evaluated if the variation of Ky with particle size and the fraction of the total radioactivity carried by particles of different sizes are
known. With these two types of data, Ky is calculated from

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