Menorandum For Dr. Libty, Commissioner, United States Atomic “nergy
Commission,
Operations
Sutj; (U) Measurenent of Local Fal2-Out in Atomic Test
fall-out in the Pacific Test Site le so complicated that the only
answer to the question is to mae e
use of a large number of ships such
or yags, etc. Certainly we can not
the lagoon. We must decide thet if
brute force measurem2nt by the
as the 99 ton fishing vessels
use rafts except possibly in
we want to go into such a measure-
ment, the price of the minimum project may be in the order of 15 to 30
million dollars depending on where we start the cash register and what
type of cost accounting is involved. The density of stations must be
at least one station every 10 miles in a direction normal to the long
axis of fall-out and one station every 25 to 50 miles in a direction
parellel to the long axis. This would involve a minimm of 40 to 120
sampling stations which I call ships.
Obviously such a proposal is out
of the question at this time for HAFDTACK. If such a proposal is taken
seriously at all, it is atsolutely mandatory that the shot or series of
shots in which it is scheduled to measure fall-out, be fired at the
command of the program director of the fall-out projects and he must
base his decision primarily on the meteorology of the day. He may heve
to wait several weeks to several months to get the right kind of surface
and upper air winds to increase the possibility of placing the downwind
fall-out pattern upon the proposed ship measuring stations. It is also
the meteorologist who will determine the magnitude of the time and space
variability of the winds aloft that have plagued practicelly all of the
measurements of fall-out in the PPG to date. There are days when the
atmosphere is most suitable toward producing a finely defined, quite
sharp, cigar shaped fall-out plot. There are other days where the fall-
out plot is scattered all over a 90° quadrant thus making the total
measurement job next to impossible.
c. It appears to me thet the determination of the total
percentage of local fall-out within the limitations of our present two
test sites is difficult, if not insurmountable. If the problems is es
important as I believe it is, perhaps it may even be worthwhile to
consider the development of new test sites in order to determine the
local fall-out.
d. When I look upon the difficulties of measuring local fallout, I wonder whether it is not worthwhile to sample the rest of the
planet in order to find out the true atmospheric burden of fission
products rather than try to determine this fror local fall-out. On the
other hand, I need not tell you of the many more problems associated
with the world-wide sampling fall-out.
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