Re: Dose point kernel and electron ranges

Alfredo,

Thank you so much for your quick answer.
Forcing single scattering with MULSOPT option seems to give very good
results, even if the boundaries are very narrow.

Ciao,
Jean-Emmanuel

-- 
_______________________________________________
Jean-Emmanuel Groetz
Laboratoire Chrono-Environnement UMR CNRS 6249
Chimie-Physique & Rayonnements
Université de Franche-Comté
16 route de Gray
25030 Besançon Cedex
France
mailto : jegroetz_at_univ-fcomte.fr
tel : +33 (0) 3 81 66 65 07
fax : +33 (0) 3 81 66 65 22
_______________________________________________
Le mardi 11 décembre 2012 à 16:18 +0100, Alfredo Ferrari a écrit :
> Dear Jean-Emmanuel
>
> surely the  boundaries between the shells are disturbing the correct
> elctron propagation if the shells are very narrow. One obvious
> solution is to force single scattering everywhere with the MULSOPT
> option, or (it should be enough) to force single scattering every time
> the conditions for multiple scattering are not met
> (eg MULSOPT with what(4)=1, what(5)=1, what(6)=1, or 2000 for single
> scattering everywhere, sdum=GLOBEMF)
>
> In general one should avoid to introduce fictitiouos boundaries
> particularly if they are very close one to another.
>
> However the lack of a spherical user binning makes it hard to do
> otherwise...
>
>                      Ciao
>                     Alfredo
>
>
>
> +----------------------------------------------------------------------+
> |  Alfredo Ferrari                ||  Tel.: +41.22.76.76119            |
> |  CERN-EN/STI                    ||  Fax.: +41.22.76.69474            |
> |  1211 Geneva 23                 ||  e-mail: Alfredo.Ferrari_at_cern.ch  |
> |  Switzerland                    ||                                   |
> +----------------------------------------------------------------------+
>
> On Tue, 11 Dec 2012, Jean-Emmanuel Groetz wrote:
>
> > Dear Fluka experts,
> >
> > I would like to calculate the dose point kernel (DPK) around an
> > isotropic electron point source in concentric water shells. We have
> > chosen four energies: 10, 30, 50 and 100 keV. Radial binning is quite
> > small, ie 1/120 of the RCSDA (continuous slowing down approximation
> > range).
> > Results at 50 and 100 keV seem to be good, compared to others codes, but
> > at 10 and 30 keV, large discrepancies can be observed. Due to the very
> > small thickness of the concentric shells of water, I am wondering if
> > some options like MULSOPT or STEPSIZE must be activated or not.
> > This kind of problem is most certainly addressed in the paper in Medical
> > Physics (2011) with fluka authors, but I could not get it in due time.
> >
> > Thank you in advance for your help.
> > Jean-Emmanuel
> >
> > --
> > _______________________________________________
> > Jean-Emmanuel Groetz
> > Laboratoire Chrono-Environnement UMR CNRS 6249
> > Chimie-Physique & Rayonnements
> > Universit?? de Franche-Comt??
> > 16 route de Gray
> > 25030 Besan??on Cedex
> > France
> >
> > mailto : jegroetz_at_univ-fcomte.fr
> > tel : +33 (0) 3 81 66 65 07
> > fax : +33 (0) 3 81 66 65 22
> > _______________________________________________
> >
> >
> >
> >