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// $Id: G4VDNAProcessInWater.icc,v 1.4 2006/06/29 19:37:05 gunter Exp $
// GEANT4 tag $Name: geant4-09-00 $

#ifdef    G4VDNAPROCESSINWATER_HH
 template<typename TotalCrossSectionPolicy, typename FinalStatesPolicy> 
 G4VParticleChange *                      G4VDNAProcessInWater<TotalCrossSectionPolicy, FinalStatesPolicy> :: PostStepDoIt(const G4Track & aTrack, const G4Step & aStep)
 {
  ValidateInWater(aTrack);
  
  G4double k=aTrack.GetDynamicParticle()->GetKineticEnergy();

  if (FinalStatesPolicy::KillIncomingParticle(k))
  {
   G4int n(aParticleChange.GetNumberOfSecondaries());
   while (n>0)
   {
    n--;
    delete aParticleChange.GetSecondary(n);
   }
   aParticleChange.Clear();
 
   aParticleChange.Initialize(aTrack);

   aParticleChange.ProposeLocalEnergyDeposit(k);
   aParticleChange.ProposeTrackStatus(fStopAndKill);
   aParticleChange.ProposeEnergy(0.); 
  }

  return G4VLowEnergyTestableDiscreteProcess::PostStepDoIt(aTrack, aStep);
 }

 template<typename TotalCrossSectionPolicy, typename FinalStatesPolicy> 
 void                                     G4VDNAProcessInWater<TotalCrossSectionPolicy, FinalStatesPolicy> :: BuildPhysicsTable(const G4ParticleDefinition & /* aParticleDefinition */)
 {
  TotalCrossSectionPolicy::BuildTotalCrossSection();
  FinalStatesPolicy::BuildFinalStatesData();
 }
 
 template<typename TotalCrossSectionPolicy, typename FinalStatesPolicy> 
 G4bool                                   G4VDNAProcessInWater<TotalCrossSectionPolicy, FinalStatesPolicy> :: IsApplicable(const G4ParticleDefinition & aParticleDefinition)
 {
  return (&aParticleDefinition)==TotalCrossSectionPolicy::IncomingParticleDefinition();
 }

 template<typename TotalCrossSectionPolicy, typename FinalStatesPolicy> 
 void                                     G4VDNAProcessInWater<TotalCrossSectionPolicy, FinalStatesPolicy> :: ValidateInWater(const G4Track & aTrack) const
 {
  G4Material * theMaterial(aTrack.GetMaterial());
  
  // Water validation consists in checking that density is 1. and that Oxigen and Hydrogen are the only two elements of the material

  if (std::fabs(theMaterial->GetDensity()*cm3/g-1.)<0.1)
   if (theMaterial->GetNumberOfElements()==2)
   {
    const G4Element * element1(theMaterial->GetElement(0));
    const G4Element * element2(theMaterial->GetElement(1));

    if ((element1->GetZ()==1. && element2->GetZ()==8.) ||
        (element1->GetZ()==8. && element2->GetZ()==1.))
     return;
   }
   
  G4String message;
  message="G4VDNAProcessInWater::ValidateInWater - Process ";
  message+=GetProcessName();
  message+=" happened in material ";
  message+=theMaterial->GetName();
   
  G4Exception(message);
 }

 template<typename TotalCrossSectionPolicy, typename FinalStatesPolicy> 
 G4double                                 G4VDNAProcessInWater<TotalCrossSectionPolicy, FinalStatesPolicy> :: GetMeanFreePath(const G4Track & aTrack, G4double /* previousStepSize */, G4ForceCondition * /* condition */)
 {
  const G4int z(10); // H2O number of electrons
  G4double k=aTrack.GetDynamicParticle()->GetKineticEnergy();

  // We suppose we are in water, one of the elements must be oxygen
  G4Material * theMaterial(aTrack.GetMaterial());
  size_t i(theMaterial->GetNumberOfElements());   
  while (i>0)
  { 
   i--;

   const G4Element * element(theMaterial->GetElement(i));
  
   if (element->GetZ()==8.)
   {
    // Number of oxigens per volume = number of water molecules per volume
    G4double density;
    density=theMaterial->GetAtomicNumDensityVector()[i];
  
    if (density<=0.)
     return DBL_MAX;

    G4double sigma_el;
    sigma_el=TotalCrossSectionPolicy::TotalCrossSection(k, z);
    
    if (sigma_el<=0.)
     return DBL_MAX;
  
    return 1./(density*sigma_el);
   }
  }
  
  G4String message;
  message="G4VDNAProcessInWater::GetMeanFreePath - ";
  message+=theMaterial->GetName();
  message+=" is not a water material";
    
  G4Exception(message);
  
  return DBL_MAX;
 }
#endif /* G4VDNAPROCESSINWATER_HH */