[fluka-discuss]: Re: About the use of MULSOPT card

From: <me_at_marychin.org>
Date: Sat, 5 Oct 2013 08:08:49 +0100 (BST)

Dear Chenyuan,

> you said the boundaries were the geometry.Is the boundary the black hole?
*No! The boundary with black hole is only one among many boundaries. A boundary
is the 界线 between regions. During a simulation, particles must make a step at
the boundary so that the code can check the material (and hence the cross
section) of the next region, so that the code knows how to continue transporting
the particle. In physical reality, such a step doesn't take place. Such
artificial steps are common in all general-purpose radiation transport Monte
Carlo codes. Boundary crossing is a basic principle.

> So,there is no need to set the photon transport energy cutoff in the EMFCUT
> card,right?
*It is up to the user whether he wants to set cutoff energies for electrons, for
photons, or for both electrons and photons. Whether you explicitly set a cutoff
or not, a cutoff will be in operation anyway. Explicitly setting the cutoff
overwrites the default values. The effective cutoff is always reported in the
output file. If you run several short simulations (even with a single history)
with and without explicit requests of cutoff energies, then do a diff / xxdiff /
mgdiff (linux commands) of the output file, you will see a beautiful demo of
what I'm trying to say.

> Is it necessary to use the MULSOPT card for my problem?
> I don't know which is more reasonable for my problem?
*That depends on the application. It depends on what you want from the
simulation. The same beam and the same geometry can be run with or without
MULSOPT; the results can be equally robust -- depending on what you are looking
for. There is no blanket recommendation.

:) mary

On 05 October 2013 at 04:18 yyc2011_at_mail.ustc.edu.cn wrote:
> Dear Mary,
>
> Please forgive me for my bother.I have some problems to consult you.
>
> First,last time,you said the boundaries were the geometry.Is the boundary the
> black hole?
>
> Second,I give an example about my doubt.The attachments include two part
> files.The files which end with _109 consider energy transport cutoff and
> single scattering.The files which end with _112 don't consider energy
> transport cutoff and single scattering.The followings are my problems.
>
> 1."EMFCUT -0.000001 0.000001 target0 target5"
> I think in the input file we only involve the electron transport,not
> photon.So,there is no need to set the photon transport energy cutoff in the
> EMFCUT card,right?
>
> 2." MULSOPT 1.0 1. 1. 3.GLOBEMF"
> According to the Fluka manual,When electrons reach the boundaries,if the
> electron energy is too small to apply Moliere theory or the step is too
> short,we can activate the MULSOPT card to set single scattering of the
> electrons.In the MULSOPT card,I set the number of the electrons single
> scattering 3.Is my understanding right? On the other hand,Is it necessary to
> use the MULSOPT card for my problem?
>
> 3.Comparing the one-dimensional and two-dimensional electron distribution
> diagrams which end with _109 and _112 ,we can find they are so different.But,I
> don't know which is more reasonable for my problem? What is your opinion?
>
> Thanks for your time.Thanks for any suggestions.
>
> Best Wishes,
> Chenyuan
>
>
>
Received on Sat Oct 05 2013 - 09:56:56 CEST

This archive was generated by hypermail 2.3.0 : Sat Oct 05 2013 - 09:57:03 CEST