(NNDC82), and 3) branching fractions and decay schemes fromtheseventh edition
of the Table of Isotopes (Le78).
Since each “nug$ide which’"we accapnted for was
the n> member of an isobaric chain, the sumber “of ¢atoms at time& would “ine.
crease or decrease relative to the number_Present. at time of detonation -because
of decay and in-ggewth phenomega of precufsor. isobars. Decay and in-growth
phenomena were aécounted for using the fal lowing equation which was originally
described by Bateman (Balé) and later recgst in a more ‘general form by Skrable
(Sk75).
-"
ee
A
n
2
i=n °
E
ist
jzn-1
(3
Aa,
=n
A; Fj, a)
|\jeis
is3¢ joi
.
"ome
>
~-. 2.5%
where
=
_
“oo
=:
40
~r;
t
Fe
a2
JU
Aie
us}, #
44)
Pom.
TT ( Pp
pi
>
a
pn
ee
A, = the number of atoms ofthentb meaber af an jsobaric chain at time
> .¢ post-detonation per oni. fisaion,: i.
s.
ay # theindependent yield= 0 oftthe ith sf|in the AD
Lsobaric chain per unit fission,
a
X; = decay constant of the jth isobar,
og
. ¢,
ae
.
oa
f5, je Lagtxbranching fraction of the jt isobar ‘leading to the.
_ecreation of the 3°th _t 1 isobar,
.
- oe = time post-BRAVO detonation.
“=
my
we
”
ORE,
“te
“hii”maeof Eqs. (3) and 5allowed us to calculate ait fission products present:“g¥the time of exposure:{ see Table 13). We also
ficluded
in Table 13,
the importan£é precursor transuganics and activation products which
were based on the.Tauzyki measurements on d#¥26 (Ts55) and the useof parent-
daughter transformation. equations given by Bateman (Bal0).
—™/
od
=
a: ‘Ron-Fission-Fragment Nuc tides Not Accounted. for.“fhe nuclides
which may have been
aye,Ste at some level but which remain unaccounted ‘forare
7 Be, 24Na,- es‘
Se, 57¢o, 580, 68¢q, 64cy, 67c¢u, 240Np, . 24lam, and
283m, The
eS
“otte
>dhort-Llived_ac iy, ‘i wproducts, 2hn aiid 56un, might
have accounted‘for
“7one.
arét the_expogur syete .
mured at 2.2 days atRongelap Is-
land. Botg tabulated. he ohotda-energy
cteunfrom a BRAVO fallou€ sample col-
lected at RongelapIsfgndz(BoS6).: The:falteutsample was reported ‘to be
analyzed at 4 days post-detonation. We determined that the spectrum has a minor
peak energy’ around 850 keV. The.santedbity of* the“peek wadabout 5 *g.7% of the
total photonTinieThe nuektde HMivin has 4 tharacterifstic photon at 847 keV
but so da”
ther oucljges” whict:may have been present (RSIC73},. ‘Mather
indicated: EeHiese shiet-lived-activation products.-m sacqgunt=for setguch as
20 to 50%Ea
oapton“intensdky ‘luring the first dayiiipa “detonat ions. howaver,
most Zana aad: WMo*activity would be.observed close to
@-potor of creation
(Ma56). tethe
rcateofBRAY0 this.yas near Namy Island,Bikini.Atoll.-:
Therefore, we: owe, that. tia ant 2ON. contributed much Bhotohtexposure at
Ronge lap“Ieland.
-
vt
be ky
ek. .
_
3 Be
cess
a
<
=,
We‘spprdkiuated” the?exposure rate contribution from all notaccounted-for nuclides -at distances fer from the detonation site on the basis of
- 37 -