ATTACHMENT "B"
As a final subject,
I would
like
to discuss some of the
measurements we will make of the low-yield shot you will see.
The efficiency of a
fission device may be expressed as the
ratio of the actual number of nuclei undergoing fission to
the total number of fissile,
i.e., uranium-235 or plutonium
239, nuclei present in the weapon,
If this is multiplied by
the energy which would be obtained by the fission of all the
fissile nuclei,
Something
the result would give the total energy yield.
like
ten or more different methods,
degrees of accuracy,
nuclear explosion,
can be used
to determine
of varying
the yield of a
A radiochemical procedure and a ball of
fire method have been generally employed for diagnostic
purposes,
the others being available in special cases,
One of
She procedures used for a rapid, but approximate, determination
of yleld has theaivantage of giving yield value within a few
minutes of the explosion.
Various other methods of yield
determination do not appear to possess any special advantages
in most instances, although they may be valuable in special
cases,
Their main interest lies in the fact that they relate
the yield
to certain phenomena accompanying the explosion.
In order that nuclear weapons may be used most effectively,
it is necessary to study various properties of the shock wave
and related phenomena.
can also be utilized
The
information obtained
in this manner
for the development of defensive procedures,
For these and other reasons,
various measurements of shock wave
phenomena are undertaken in connection with nuclear weapons
tests.
One method used for observing shock arrival times was to
attach blast switches
to a number of cables held by ballo-ns,
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Attachment "B"