SLIDE 14
Comparison of Bikini Ash to unfractionated fallout. The per cent of fallout
beta activity due to fission products present on day 26 after formation was
tabulated. The hypothetical beta activity was based on a fallout composition
which was unaltered due to chemical or physical mechanisms which affected
certain fission product nuclides.
This unaltered composition was referred to
as unfractionated.
This unfractionated fallout was calcylated from
thermonuclear neutron fission data given by Crocker for
U (Cr65).
The comparison between per cents, based on the measured values of Bikini
Ash beta activity and unfractionated fission product beta activity, required
conversion of the Yamatera and Tsuzuki data sets (Ya56, Ts55) into percent
fission product beta,actiyity. That is, we exclude the befg_activity of the
activation products
S,
Ca and the 5ygnsuranic nuclide
U for comparison
purposes.
It was assumped by us that
U, which represented 20% of the beta
activity on day 26 in the Tsuzuki results represented 20% of the beta activity
in the Yamatera data.
As previously implied, the term fractionation indicated alterations of
nuclide composition in fallout debris.
The ratio of two nuclides in fallout
was often used to describe fractionation quantitatively (§r61)- The
denominator of the ratio was taken to be the activity of
“~Zr (Fr61).
quantify fractionation between two nuclides,
To
the beta activity ratios were
compared by Freiling (Fr61). The term “degree of fractionation” was used by
him and represented the range of variability of the nuclide ratio.
revi
of
Ja
ese
ults indi
d to us that the activity ratios
for 13270 132 Bf Pay Ce, ToerRh and Teacape (ratioed to measure 95 Nt
beta activity) did not differ by a
tor greater than abeut 1.5
from the
unfractionated ratios.
Ratios for 186 > er fy, BBecy, ro8s
d 1435,
differed by about a factor of 2, and
Sr and 1
re,
29n6 differed, by about
actor
3 re
ive
the
rac
nated
fos.
nuclides
Y,
tober Pane 185° 18200 ¥35r° Heecepe, [eae tnd17x 4 were in greater
abundance relative to unfractionated debris.
DAY 26 COMPOSITION OF BRAVO
FALLOUT
Nuclide
ey
ms
Ss
“Ca
271
22 Du (a)
Greater Than Hypothetical
"ty
Ru, Rh, Te,
129mm MSD WINg
Hypothetical Thermonuclear
% Bikini Ash
Neutron Fission, %
Beta Activity
Total Beta Activity
0.013
8.0
0.031
4.1
0.20
_
0.0004
_
_
0.05
20
—
Less ThanHypothetical
Sr,
Sr, MY,
Ba, M4073
Ru,
19
1,
Approximately
Same As Hypothetical
7,
Nb,Te, MT,
Ce, M4 Pr