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Question Understanding of PhysListEmStandardNR physics constructor 

Forum: Physics List
Date: 30 Jan, 2013
From: Constantin Csato <Constantin Csato>

Dear Geant4 experts,

I’m simulating ions penetrating through a thin silicon foil (thickness of 3-10µm) with an energy in the range of 1-10 MeV. I’m using the “PhysListEmStandardNR” physics constructor from the Em Workgroup. I compared my results with SRIM and there are just small deviations. Now I’m trying to understand the physics list to see the difference between SRIM and Genat4. At that point I have some questions concerning the physics list.

In the physic list the following process for ions can be found:

  G4ScreenedNuclearRecoil* nucr = new G4ScreenedNuclearRecoil();
  G4double energyLimit = 100.*MeV;
  nucr->SetMaxEnergyForScattering(energyLimit);

else if (particleName == "GenericIon" ) {

     G4hMultipleScattering* msc = new G4hMultipleScattering();
      G4DummyModel* dm = new G4DummyModel();
      dm->SetLowEnergyLimit(0.0);
      dm->SetHighEnergyLimit(energyLimit);
      msc->AddEmModel(0, dm);

      pmanager->AddProcess(msc, -1, 1,1);

      G4ionIonisation* ion = new G4ionIonisation();
      ion->SetStepFunction(0.1, um);
      pmanager->AddProcess(ion, -1, 2, 2);

      pmanager->AddDiscreteProcess(nucr); 

From the source code you can see that 3 processes are implemented: G4ionIonisation, G4hMultipleScattering and G4ScreenedNuclearRecoil. G4ionIonisation process calculates the energy loss due to the ionization. G4ScreenedNuclearRecoil process the elastic scattering.

I’m not quite sure about the G4hMultipleScattering. According to the physics reference G4hMultipleScattering calculates the elastic scattering according to the MSC approach.

To me it seems that two processes for the elastic scattering are implemented, is that correct?

According to which approach is the scattering calculated, MSC or single scattering? In the description of the physics list it is written “multiple scattering processes for protons and ions are substituted by single scattering process”, but why there is the implementation of G4hMultipleScattering?

Furthermore I’m interest in sputtering. Generally G4ScreenedNuclearRecoil delivers recoil events and this almost everything that is needed for simulation of sputtering. However, has anyone of you some experience with simulation of sputtering or maybe some code which I could ‘recycle’.

I would be happy for any answer or some hint for some literature.

King regards, Constantin Csato

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1 Idea: Re: Understanding of PhysListEmStandardNR physics constructor   (Vladimir Ivanchenko - 05 Feb, 2013)
(_ Ok: Re: Understanding of PhysListEmStandardNR physics constructor   (Constantin Csato - 05 Mar, 2013)
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