A

n

.

=

isn

j=n-l

izl

jel

I

T

LK:
J

f:

+4]

“JJ

jan
j=i

a2

Ast

J

m

p=i

(4)

(Ay = r

p#j

where

A, = the number of atoms of the nth member of an isobaric chain at time
t post detonation per unit fission,
Aj = the independent yield at t = 0 of the ith isobar in the An
isobaric chain per unit fission,

Xs = decay constant of the jth isobar,
= branching fraction of the jt} isobar leading to the
creation of the ch + 1 isobar,
t = time post BRAVO detonation.

The use of Eqs. 3 and 4 led to the inclusion in Table 5 of all
fission products with the exclusion of only’ a few of the dosimetrically insignificant ones.

A few important transuranics and activation products were ine luded

in Table 5 based on the Tsuzuki measurements on day 26 fallout (Ts55) and use of

parent-daughter transformation equations given by Bateman (Bal0).
d.

Non-Fission Fragment Nuclides Not Accounted For
The nuclides which may have been present at some level but re-

main unaccounted for are Be-7, Na-24, Mn-56, Fe-55, Fe-59, Co-57, Co-58, Co-60,
Cu-64, Cu-67, U-240, Np240m, Np-240, Am-241 and Cm-242.

Two short lived activa-

tion products, Na-24 and Mn-56, might have accounted for some of the exposure
rate measured at day 2.2 at Rongelap Island.

Borg (Du56) tabulated the photon

energy spectrum from a BRAVO fallout sample collected at Rongelap Island.
fallout sample was reported to be analyzed at 4 days post detonation.
trum showed a significant peak energy at 850 keV.

The

The spec-

Mn-56 has a characteristic

photon at 847 keV but so do about 30 other nuclides that were present in fallout
at that time (RSIC73).

Mather (Du56) indicated that short-lived neutron activa19

Select target paragraph3