SLIDE Ll
Ratio of nuclide to total fallout activity. The ratio of 1297 activity to
total fallout activity would help in determining if the archival soil analysis
for radioiodine corresponded to other measured or hypothetical ratios. The
surface~soil activity of each nuclide measured by Brauer was estimated for 0.5
days post detonation.
This was the assumed time of cessation of fallout at
Rongelap.
The value for the nuclide activty per unit mass of soil at the
cessation of fallout was estimated from the best fit of archival soil
results.
The value of the denominator used in the ratio was based on measured
gross beta activity.
Gross beta analysis was done on soil samples taken on
March 8, 1954 (0C68) from Rongelap Atoll.
Hypothetical nuclide activity relative to total, fission product activity
was estimated from data on thermonuclear fission of
U given by Crocker
(Cr65). Total activity values given by Crocker do not account for chemical
and physical deletion or enhancement of fission products, production of
activation products or production of transuranics.
Total acitivity per 10,000
fissions at 0.5 days was taken from Table 3 of Crocker's report (Cr65).
Individual nuclide activities were calculated by Crocker's methods and the
original inupt data (Cr63).
The ratio derived from BRAVO fallout measurements was based on Bikini Ash
activity.
For
iE er 1295p) phe ratios were not similar however sample size was small.
Eu and
Cs, results were in accord at both Rongelap and Utirik.
archival soil results for
I at Rongelap and Utirik were distinctly
different from the thermonuclear fission results and Bikini Ash results.
The
.
SURFACE ACTIVITY RATIOS 0.5 DAYS
POST DETONATION
Archival Soil
BRAVO Fallout
Measurements
Thermonuclear Fission “*U
Nuclide Activity
Nuclide Activity
Nuclide Activity
Gross Beta Activity
Bikini Ash Beta Activity
Fission Product Activity
Measurements
Nuclide
125
Sb
al
acs
Eu
1.8X10
-7
6
Hypothetical
2.6X10_9
4.5X10
3.5X10--?
8.310
7T.1X10
9.6X10
7.6X10"°
7.1X10-4
16
4.610
-6
3.5X10
5.5X10-°