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// $Id: G4FinalStateChargeDecrease.cc,v 1.2 2007/11/09 20:11:04 pia Exp $
// GEANT4 tag $Name:  $
// 
// Contact Author: Maria Grazia Pia (Maria.Grazia.Pia@cern.ch)
//
// Reference: TNS Geant4-DNA paper
// Reference for implementation model: NIM. 155, pp. 145-156, 1978

// History:
// -----------
// Date         Name              Modification
// 28 Apr 2007  M.G. Pia          Created in compliance with design described in TNS paper
//
// -------------------------------------------------------------------

// Class description:
// Reference: TNS Geant4-DNA paper
// S. Chauvie et al., Geant4 physics processes for microdosimetry simulation:
// design foundation and implementation of the first set of models,
// IEEE Trans. Nucl. Sci., vol. 54, no. 6, Dec. 2007.
// Further documentation available from http://www.ge.infn.it/geant4/dna

// -------------------------------------------------------------------


#include "G4FinalStateChargeDecrease.hh"
#include "G4Track.hh"
#include "G4Step.hh"
#include "G4DynamicParticle.hh"
//#include "Randomize.hh"

#include "G4ParticleTypes.hh"
#include "G4ParticleDefinition.hh"
#include "G4SystemOfUnits.hh"
//#include "G4ParticleMomentum.hh"
#include "G4DNAGenericIonsManager.hh"

G4FinalStateChargeDecrease::G4FinalStateChargeDecrease()
{
  name = "ChargeDecrease";
  lowEnergyLimit = 1 * keV;
  highEnergyLimit = 10 * MeV;
}


G4FinalStateChargeDecrease::~G4FinalStateChargeDecrease()
{}
 

const G4FinalStateProduct& G4FinalStateChargeDecrease::GenerateFinalState(const G4Track& track, const G4Step& /* step */)
{
  // Clear previous secondaries, energy deposit and particle kill status
  product.Clear();

  G4double inK = track.GetDynamicParticle()->GetKineticEnergy();

  G4ParticleDefinition* definition = track.GetDefinition();
  G4int finalStateIndex = cross.RandomSelect(inK,definition);
 
  G4int n = NumberOfFinalStates(definition, finalStateIndex);
  G4double waterBindingEnergy = WaterBindingEnergyConstant(definition, finalStateIndex);
  G4double outgoingParticleBindingEnergy = OutgoingParticleBindingEnergyConstant(definition, finalStateIndex);
  
  G4double outK = 0.;
  if (definition==G4Proton::Proton())
    outK = inK - n*(inK*electron_mass_c2/proton_mass_c2) - waterBindingEnergy + outgoingParticleBindingEnergy;
  else
    outK = inK - n*(inK*electron_mass_c2/(3728*MeV)) - waterBindingEnergy + outgoingParticleBindingEnergy;
  
  if (outK<0)
    {
      G4String message;
      message="ChargeDecreaseDingfelder::GenerateFinalState - Final kinetic energy is below 0! Process ";
      G4Exception(message);
    }
  
  // Primary particle
  product.KillPrimaryParticle();
  product.AddEnergyDeposit(waterBindingEnergy);
  
  //Secondary particle
  G4DynamicParticle* aSecondary = new G4DynamicParticle(OutgoingParticleDefinition(definition, finalStateIndex), 
							track.GetDynamicParticle()->GetMomentumDirection(), 
							outK);
  
  product.AddSecondary(aSecondary);
  
  return product;
}

G4int G4FinalStateChargeDecrease::NumberOfFinalStates(G4ParticleDefinition* particleDefinition, 
						      G4int finalStateIndex )
  
{
  if (particleDefinition == G4Proton::Proton()) return 1;
  
  G4DNAGenericIonsManager*instance;
  instance = G4DNAGenericIonsManager::Instance();
  
  if (particleDefinition == instance->GetIon("alpha++") ) 
    {
      if (finalStateIndex==0)  return 1;
      return 2;   
    }
  
  if (particleDefinition == instance->GetIon("alpha+") ) return 1;
  
  return 0;
}


G4ParticleDefinition* G4FinalStateChargeDecrease::OutgoingParticleDefinition (G4ParticleDefinition* particleDefinition, 
									      G4int finalStateIndex) 
{
  G4DNAGenericIonsManager * instance(G4DNAGenericIonsManager::Instance());
  
  if (particleDefinition == G4Proton::Proton()) return instance->GetIon("hydrogen"); 
  
  if (particleDefinition == instance->GetIon("alpha++") ) 
    {
      if (finalStateIndex == 0) return instance->GetIon("alpha+"); 

      return instance->GetIon("helium");    
    }
  
  if (particleDefinition == instance->GetIon("alpha+") ) return instance->GetIon("helium");    
  
  return 0;
}


G4double G4FinalStateChargeDecrease::WaterBindingEnergyConstant(G4ParticleDefinition* particleDefinition, 
								G4int finalStateIndex )
{
  // Ionization energy of first water shell
  // Rad. Phys. Chem. 59 p.267 by Dingf. et al.
  // W + 10.79 eV -> W+ + e-
  
  G4DNAGenericIonsManager * instance(G4DNAGenericIonsManager::Instance());
  
  if(particleDefinition == G4Proton::Proton()) return 10.79*eV;

  if (particleDefinition == instance->GetIon("alpha++") ) 
    {
      // Binding energy for    W+ -> W++ + e-    10.79 eV
      // Binding energy for    W  -> W+  + e-    10.79 eV
      //
      // Ionization energy of first water shell
      // Rad. Phys. Chem. 59 p.267 by Dingf. et al.

      if (finalStateIndex == 0) return 10.79*eV;
  
      return 10.79*2*eV;
    }

  if (particleDefinition == instance->GetIon("alpha+") ) 
    {
      // Binding energy for    W+ -> W++ + e-    10.79 eV
      // Binding energy for    W  -> W+  + e-    10.79 eV
      //
      // Ionization energy of first water shell
      // Rad. Phys. Chem. 59 p.267 by Dingf. et al.

      return 10.79*eV;
    }
  
  return 0;
}


G4double G4FinalStateChargeDecrease::OutgoingParticleBindingEnergyConstant(G4ParticleDefinition* particleDefinition, 
									   G4int finalStateIndex)
{
  G4DNAGenericIonsManager * instance(G4DNAGenericIonsManager::Instance());
  
  if(particleDefinition == G4Proton::Proton()) return 13.6*eV;

  if (particleDefinition == instance->GetIon("alpha++") ) 
    {
      // Binding energy for    He+ -> He++ + e-    54.509 eV
      // Binding energy for    He  -> He+  + e-    24.587 eV

      if (finalStateIndex==0)	return 54.509*eV;
      
      return (54.509 + 24.587)*eV;
    }
  
  if (particleDefinition == instance->GetIon("alpha+") ) 
    {
      // Binding energy for    He+ -> He++ + e-    54.509 eV
      // Binding energy for    He  -> He+  + e-    24.587 eV
      
      return 24.587*eV;
    }  
  
  return 0;
}