Re: [VMC] VMC and Ion definition

From: Ivana Hrivnacova (Ivana.Hrivnacova@cern.ch)
Date: Wed Jan 14 2004 - 18:56:46 MET


 Hi Denis,

 To enable delta rays in Geant3, you have to
 set flags in g3Config.C
    gMC->SetProcess("DRAY",1);
    gMC->SetProcess("LOSS",1);
 In Geant4, delta rays are produced by default.

 To get comparable results, you should run both
 G3 and G4 with the same cuts. This is a bit tricky,
 as G4 uses cuts in range per particle while
 G3 cuts in energy per tracking medium.
 In VMC, you can set cuts in energy via
 TVirtualMC::Gstpar() function
 (have a look at Ex03DetectorConstruction class in
  E03 example)

 To take these cuts setting into account by Geant4,
 you have to activate the TG4SpecialCuts process,
 by adding:
  /mcPhysics/setSpecialCuts true
 in Geant4 configuration macro (g4config.in).
 (This command is defined via Geant4 VMC default 
 physics list; if you use your own G4 physics list
 this command is not available;
 then you will have to register the
 TG4PhysicsConstructorSpecialCuts physics in it.)

 Best regards,

 Ivana

==============================================================
e-mail:  Ivana.Hrivnacova@cern.ch
address: Institut Physique Nucleaire, 91406 Orsay, France
phone:   (33) 01 69 15 65 94
==============================================================

On Wed, 14 Jan 2004, Denis Bertini wrote:

> Hi
> I would like to study the production of delta-electrons when shooting a
> AU gold ion beam through
>  an AU thin target.
> I  am using VMC for that. and the new functionality DefineIon(...);
>  Now i would like to know what should be my setup (G3_G4Config.C) for
> Geant3 and Geant4 in order to be able to
>  compare what VMC_Geant3 and VMC_Geant4  gives ?
>   Thanks,
>                                                         Denis Bertini
> 
> 
> 
> 

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