0018933
S
{nitially, the curves shown for Oak and Koa may be only the relatively flat
.
part which appears for Walnut at a later time,
.
This seems to be consis-
tent with what is surmised about the cloud particle size distribution for
land and water shots,
In addition to the samples from the light and variable wind layer,
there were also a number of collections made on‘each shot at lower altitudes,
Although not of direct application to the project objectives, the
radiochemical data for these samples is instructive since it shows how the
nuclide composition of the particulate matter varied with altitude,
Some
of the samples came from the bottom portions of the clouds, but those
collected at the lowest altitudes may have been below the base of the mushroom and would perhaps be considered as fallout,
Table 3,3 gives a summary
of the Sr99 and Cs!37 R-values for the three shots.as related to altitude and
time of collection,
The R-values for the samples marked with an asterisk
were calculated as gross figures from the R-values for the size-separated
t
fractions, For the land surface shot the R-values show a general increase
with altitude, attaining values at 60,000 feet which are 10 (Sr?9) to 40 (Cs137)
times those expected for the detonation,
The water shot R-values are rela-
tively insensitive to altitude, and the enrichment factor is not more than 2
for either nuclide,
Samples collected below 45,000 feet may be from the