00339361.pdf

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Two qualitative features“o? d2ae8e&& &$ Prhaps wrth commenting
upon. It is seen that the U*38 fission rate falls off more sharply as a
function of radius in the tuballoy tamper than it does in the nickel tamper.
This behavior would seem to show that tuballoy more effectively shifts the
neutron spectrum toward lower energies than does nickel. With this in mind,
it might be expected that gold detectors should show activities which fall
off more sharply In nickel than in tuballoy. Just the opposite of this is
observed, however$ in the first few inches outside of th core. Such a response
is probably indicative of the fact that the low
of neutrons emerging from the core has a longer capture mean free path in
nickel than in tuballoy~
energy portion of the spectrum
Aside from such qualitative considerations, however, the main value
of these measurements lies in the opportunity offered for comparing
observed detector responses with those predicted on the basis of Monte
Carlo calculations, as a means of checking the assumed values of cross
sections for elastic and
calculations.
APPROVED FOR PUBLIC RELEASE
Inelastic scattering processes that go into such
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APPROVED FOR PUBLIC RELEASE