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