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 calcyhated 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 besgactivity of the
activation products
Ss,
Ca and the GRgnsuranic 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 (§g6!). 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 patios
for 13270. P27. Bf Payce, [BeeuRh and Teacape (ratioed to measure 957 END
beta activity) did not differ by a
tor greater than abgut 1.5
from the
unfractionated ratios. Ratios for 186gata, th at, 885 Y, rods? and 1435,
differed by about a factor of 2, and 8 Sr and I Bre, 29T 6 differed by about
actor
3 re
ive
the
rac
nated
fos.
T
nuclides
Y,
tobeer, Pare 185oe° 182ne° Y38r° ee teee, Cee and sae were in greater
abundance relative to unfractionated debris.
DAY 26 COMPOSITION OF BRAVO
-
Nuclide
Xy
ty
Bs
ca
v3 0
Pu (a)
FALLOUT
% Bikini Aah
Beta Activity
Hypothetical Thermonuclear
Neutron Fission, %
Total Beta Activity
0.013
8.0
0.05
0.031
4.1
_
20
0.0004
—
—
0.20
_
Greater Than Hypothetical
Less Than Hypothetical
12am NS py Mintg
MB, 14 La
*y, Ry, ieRh Te,
nee SE eyey tT,
19
Approximately
Same As Hypothetical
P7r Nb, MTe, Sy,
Ce, 144 Pr