# RE: [fluka-discuss]: Fluka lattice

From: Alberto Fasso <fasso_at_mail.cern.ch>
Date: Mon, 8 Sep 2014 17:00:59 +0200

Dear Sanjay,

my friend Anna Ferrari has suggested to me a nice way to do your geometry
without too much trouble.
Divide your drum into several smaller identical volumes. Make one of those
volumes your lattice prototype and fill it by hand with a reasonable
number (perhaps a few dozen) of cylindrical chunks, randomly positioned
and oriented. When doing that, make sure that they are closely packed but
not overlapping.
Then, use the command LATTICE to build the whole drum by repeating the
prototype as many times as necessary.

It will be up to you to define a prototype volume small enough to allow
positioning all the chunks by hand, and large enough that the resulting
drum be filled in a way that looks sufficiently random to the incident
neutrons

Alberto

> From: Fasso, Alberto <fasso_at_slac.stanford.edu>
> Date: Mon, 8 Sep 2014 07:46:06 +0000
>
>
> 2 cm is not very small compared to the likely attenuation length, therefore
> the approximation I suggested (a material of average density) is not acceptable.
> Of course you can use the LATTICE option: but if each cylinder has a random
> position and orientation it is probably difficult to avoid overlapping them with
> each other. In MCNP, I guess, you would have a similar problem.
>
> Alberto
>
> From: sanjay andola <andolas.007_at_gmail.com>
> Sent: Sunday, September 7, 2014 10:27 PM
> To: Fasso, Alberto
> Subject: Re: [fluka-discuss]: Fluka lattice
>
> 1 mts long 40 cm dia drum is half filled with the small 2 cm cylindrical
chunks of SS. chunks can be taken as cylinders. can it be done like in
MCNP in with lattice card or i have to take individual chunk geometry?
>
> thanks
>
> On Sat, Sep 6, 2014 at 2:33 PM, Fasso, Alberto
<fasso_at_slac.stanford.edu<mailto:fasso_at_slac.stanford.edu>> wrote:
> ________________________________
> Dear Sanjay,
>
> can you be a little more specific?
> - How large is the "large number of chunks"? Hundreds? Thousands?
Millions?
> - Have they all the same shape? Is it a simple shape?
> - How small are the "small pieces?", with respect to the size of the
drum?
> If the number of the pieces is very large, and they are much smaller
than the drum, and if the only thing you are interested in is the neutron
attenuation, you can define a material of average density, for instance by
defining a COMPOUND made of air and metal.
>
> Alberto
>
> From:
owner-fluka-discuss_at_mi.infn.it<mailto:owner-fluka-discuss_at_mi.infn.it>
<owner-fluka-discuss_at_mi.infn.it<mailto:owner-fluka-discuss_at_mi.infn.it>>
on behalf of sanjay andola
<andolas.007_at_gmail.com<mailto:andolas.007_at_gmail.com>>
> Sent: Friday, September 5, 2014 11:16 PM
> To: fluka-discuss_at_fluka.org<mailto:fluka-discuss_at_fluka.org>
> Subject: [fluka-discuss]: Fluka lattice
>
> Dear all
> I want to simulate a number of small pieces of metal chunks
enclosed in a drum. the Drum is half filled with such type of material,
this geometry to see the neutron attenuation due to this material.
> do i have to create such large number of chunks or i can do this with
the lattice card?
>
>
> Thanks in advance
> Sanjay
>
>
>
> --
> Thank & Regards
> Sanjay C Andola
> Scientific Officer C
> Applied Physics Division
> BARC Trombay
> Mumbai 400085
Received on Mon Sep 08 2014 - 18:27:24 CEST

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