When to use self-shielding materials?

From: George Kharashvili <georgek_at_jlab.org>
Date: Thu, 11 Oct 2012 15:19:54 -0400 (EDT)

Dear FLUKA experts,

Could you please explain (again!) what is the disadvantage of using a self-shielded neutron cross section?
One of the advanced course lectures has general guidelines on this issue. It says to use self-shielded materials with
  "Bulky (huge) pieces that are very pure
(containing only one isotope)" and not to use with "small iron, copper, lead, aluminum pieces and diluted materials".
-What is considered small and what happens if one uses self-shielded material with small objects?

FLUKA manual also says that the presence of even small amounts of impurities
is generally sufficient to smooth out the effect of self-shielding and, if I understood
it correctly, it should only be used with very pure, single isotope materials.
-If so, when should we use self-shielded natural lead and natural tungsten?

I am modeling photon and neutron activation in thin foils (0.01-0.1 mm thick)
that are placed inside a 15x20x40 cm^3 beam dump. The dump is made of lead and
tungsten and is exposed to 3GeV electron beam. Should I use self-shielded
lead and tungsten for the bulk of the dump and non-self-shielded lead for thin lead samples?

Thank you in advance for your answer(s).

Received on Fri Oct 12 2012 - 10:08:36 CEST

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