Re: Thermal neutrons in FLUKA

From: Alberto Fasso' <fasso_at_SLAC.Stanford.EDU>
Date: Fri, 12 Apr 2013 06:00:19 -0700 (PDT)

Dear Inesh,

first of all I would like to ask you to send your questions not to me
personally, but to the FLUKA discussion list, where you are more sure to find
somebody who can answer you. (I take the liberty to post this answer, together
with your question, on that list, so that other users can profit from it).

Now, about your question: light fragments such as tritons, when they are
produced in interactions of neutrons of energy lower than 20 MeV, are not
transported by FLUKA, as you can read in the FLUKA Manual, Sec. 10.3.3.
Only exceptions are recoil protons, protons from N(n,p) reactions, and
light fragments from neutron capture in 6-Li and 10-B, (the latter only if
pointwise transport has been requested by the user).
Therefore, you can never expect to get a fluence of tritons different from
zero, if the tritons are produced by 14 MeV neutrons.

Apart from this, I warn you against considering answers which were given on
the discussion list a too long time ago (the one you reported is from
six years ago). Several things have changed in FLUKA since 2007, especially
concerning low-energy neutrons (but the answer above is still valid).

Best regards,


On Fri, 12 Apr 2013, Inesh Kenzhina wrote:

> Dear Alberto,
> My name is Inesh Kenzhina, I am from Al-Farabi Kazakh National University,
> I have found your answers at FLUKA discussion
> page
> I have such kind of problem - I need to irradiate Be target by neutrons of
> 14Mev. But fluence of tritons is always appeared to be zero. Energy cut-offs
> are set, Low-Neut and Low-Bias have been written to the input file. But,
> anyway, triton fluence is zero. If you are aware of any considerations how
> to cope with that, I will be very grateful to you.
> Thank you in advance,
> Inesh kenzhina
Received on Sat Apr 13 2013 - 14:09:39 CEST

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