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

From: <me_at_marychin.org>
Date: Fri, 4 Oct 2013 13:44:44 +0100 (BST)

Dear YuanChen,

> But,what is the meaning "at boundaries"?
*At boundaries in the geometry.

> What is the step on earth?
*Particle steps. Monte Carlo simulations consist of particle steps: some are
artificial, others are physical.

> So,I suspect the method of dealing with single scattering and multiple
> scattering is different
*That's the whole purpose of doing multiple scattering. The rationale behind
multiple scattering is the same for different Monte Carlo codes; standard Monte
Carlo texts therefore apply and you might wish to refer to them for better
understanding. The algorithm and implementation differ from code to code, but
under normal circumstances I don't think one needs to dig into such details.

It is a compromise between speed and accuracy. On the one hand, we don't want
artefacts. On the other hand, without multiple scattering many simulations would
become prohibitive even with present-day CPU capability. How bad can artefacts
be? That depends on the geometry and transport setup as well as the scoring.

:) mary


On 03 October 2013 at 05:11 yyc2011_at_mail.ustc.edu.cn wrote:
> Dear Fluka experts,
>
> I'm very confused when I use the card MULSOPT.The followings are my problems.
>
> First,for sudm=GLOBAL,GLOBEMF,when I set what(4)>0,I activate single
> scattering at boundaries or for too short steps.But,what is the meaning "at
> boundaries"?Are the boundaries the target boundaries?On the other hand,what is
> the meaning "too short steps"?
> What is the step on earth?Why we must set single scattering at boundaries or
> for too short steps?
>
> Second,When what(6)>0,according to the Fluka manual,I can set the number of
> single scatterings to be performed when crossing a boundary.Since this is a
> single scattering,Why can I set the number of single scattering?In my
> eyes,when a particle cross a boundary,if I activate single scattering,the
> particle cross the boundary one-time.So,I feel confused about the meaning of
> the number of single scattering.How should I understand the number of single
> scatterings?
>
> Third,when I add the card MULSOPT in my input file,the run time is very
> long.What cause this?So,I suspect the method of dealing with single scattering
> and multiple scattering is different.If you can,Could you explain the method
> of dealing with single scattering and multiple scattering?
>
> Best Wishes
> YuanChen
>
>
>
Received on Fri Oct 04 2013 - 15:34:18 CEST