A very similar question has been submitted recently. See:
http://www.fluka.org/web_archive/earchive/new-fluka-discuss/6774.html
See the answer to that question. In short: you need a LAM-BIAS
command to enhance the probability of a neutron interacting in
such a thin layer.
Alberto
On Tue, 3 Jun 2014, James Ryan wrote:
>
> Dear experts,
>
>
> I'm trying to run a simulation involving a thin target of Uranium (50nm
> thin) and investigating fissions in the target when incident with a white
> neutron source (sampled from a collision tape produced by proton-lead
> spallation).
>
>
> I have attached a simple input file which I'm using, but no fissions are
> occurring.
>
>
> When I increase the thickness of the uranium to 5um I can see fissions in
> the output, but none at 50nm or 500nm thick. Is there anything I can do to
> encourage fissions in the 50nm version?
>
>
> Thanks very much,
>
>
> James Ryan Nuclear FiRST DTC
> University of Manchester
> james.ryan-4_at_postgrad.manchester.ac.uk
> +447890 486 709
>
>
>
Received on Tue Jun 03 2014 - 16:06:45 CEST