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of the radiomeclide composition of local fallout as determined from the rocket
samplese
The influence of the enviroment on fallout partition was to be inves-
tigated by participation in events over land and water surfacese
The basic hypothesis on which the determination of fallout partition by
the measurement of relative enrichment is based is that the increase of a
volatile material with respect to a refractory material (eoges Kr 88 with respect
to Mo?9) occurs principally as a result of fallout of the refractory material
(i.e., the only force producing separation is gravitation).
If this hypothesis
is correct, then the Mo?9 left in the cloud region sampled compared to the Kr 88
nay be interpreted as the fraction of refractory debris which will be distributed
in"world-wide™ fallout. This fraction is given by
_ fR°°(e8)] 5
[n°9(e8)] c
If, however, other forces operate on the particles, particularly centrifugal forces which exist during the initial phase of cloud rise or turbulent
forces which may exist for several hours due to temperature inequalities, the
possibility exists that separation of gases or small particles from large particles
‘may cccur without requiring real fallout of refractory materiale
It is also possible
that separation of the more volatile products from the less volatile may occur in
the gas phase. as a function of altitude in the cloud without requiring separation
of large particles from small particles or particles from permanent gasese
If these
processes occur, even a large enrichment of volatile material near the top of the
cloud would not necessarily be attributable principally to fallout.
To help determine whether these elternative processes are important, it is
considered necessary to obtain very early data for R values of relatively volatile