Notes on Mtg, 25 Aug '51
Reines suggested there are other factors to consider, e.g,
the time the plane remained in the cloud, where it was, etc. Piank
said that they have correlations on other shots--there 1s possibly a
factor of 10, perhape 100, to be gained by altitude, i.e., the nearer
the plane is to the puff the better samples obtained (this is not to
gay the plane should go through the puff). Drone aircraft are difficult
to control, and it 4s hoped to improve the situation a great deal by
using manned aircraft and sampling for longer time intervals. It is
also hoped topick up a factor of e© by usingbetterandlarger collec-
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tore.
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It was suggested that, in view of the difficulties, the work
on rockets should be resumed, Plank explained that the fact that super
testa were contemplated was a large reason for discontinuing work on
both the rockets and the filter-bomb idea:
the problem of landing and
recovering such devices inconnection with an island or underwater shct
is quite serious and waterproofing them very difficult. In addition,
the temperature of the ball of fire in the early states is so high as
to burn up the rockets. For example, on @ 20-kiloton bomb the rockets
might have been shot through the cloud successfully at 20-3 seconds;
on George, they would not have survived.
C.
Neutron Measurements:
“External Threshold Detectors
Buclear Emilsion Plates
Both these experiments have difficulties which may preclude
their being done:
(a) the requirement for real estate and stations,
(b) the intensity is @ problem due to the high attemuation of the bomb
parts and the fact that the detectors must be out at a great distance
because of the crater size, adding en additional problem of air attenuation. Thus, the interpretation of the data, if any are obtained, vill
be extremely difficult.
The number of li-Mev neutrons which come out is estimated to
be somewhere between that of Item and George, which is rather small,
and therefore the measurement would have to be done under the same
conditions but with a mich larger blast problem.
(Rosen obtained good
plates at 1200 yds on the George shot, but this was about the maxima
distance.) Delayed neutrons should not be too mich of @ problem; Hall
etated that 1 Mev is about the highest energy observed in delayed
neutrons. Teller raised the question of delayed fisaions, vhich might
play havoc with this experiment. However, since the Phonex experiment
uses collimation, it would not see a very large proportion of the bomb
materials.
Another difficulty is the problem of recovery, especially in
the case of the muclear emulsion plates which mist be recovered soon
because of pealing in a vacuum.
~13-
!