Re: [VMC] VMC: Hadron generation

From: Rene Brun (Rene.Brun@cern.ch)
Date: Tue Oct 28 2003 - 09:40:57 MET


Hi Paolo,

The VMC does not provide a general interface to decide between Fluka or Gheisha
models. When using the Geant3 implementation, you have to provide
functions guhadr/guphad to make this choice.

TrackTime returns the time in the lab frame since the primary interaction
defined by the primary vertex.

Rene Brun

Paolo MAESTRO wrote:
> 
> Hi,
> in a previous mail I asked which is the default hadronic package
> used by geant3 and this was the answer:
> 
> Rene Brun wrote:
> > Hi Paolo
> > I will answer your geant3 related questions:
> > the default hadronic package is defined by guhadr in the guser
> > subdirectory. This routine calls Gheisha. you can redefine this routine
> > to call Fluka instead. For example in the gexam4 example, we have
> >  SUBROUTINE GUHADR
> > #include <gcphys.h>
> > C
> > C
> > C   GHEISHA only if IHADR<3 (default)
> >
> > IF(IHADR.NE.4) THEN
> >  CALL GHEISH
> > ELSE
> >   CALL FLUFIN
> > ENDIF
> > END
> 
> This is clear to me if I use fortran code or I run geant3 from ROOT.
> But if I use VMC how can I call Fluka?
> Is there some option I can set to switch from Gheisha to
> Fluka (for instance: IHADR=4 has already this effect?)
> or this requires to
> modify some code in the BuildPhysics method of TVirtualMC?
> 
> I would have also another question: does the method TrackTime() of
> TVirtualMC class give the time of a certain track calculated in the
> laboratory frame and starting from t=0 corresponding to the primary
> particle generation?
> Thanks.
> Best regards
> 
>                 Paolo



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