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//
//
// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:     G4ionIonisation
//
// Author:        Vladimir Ivanchenko
//
// Creation date: 07.05.2002
//
// Modifications:
//
// 26-12-02 Secondary production moved to derived classes (VI)
// 24-01-03 Make models region aware (V.Ivanchenko)
// 05-02-03 Fix compilation warnings (V.Ivanchenko)
// 13-02-03 SubCutoff regime is assigned to a region (V.Ivanchenko)
// 15-02-03 Add control on delta pointer (V.Ivanchenko)
// 23-05-03 Add fluctuation model as a member function (V.Ivanchenko)
//
// Class Description:
//
// This class manages the ionisation process for ions.
// it inherites from G4VContinuousDiscreteProcess via G4VEnergyLoss.
//

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

#ifndef G4ionIonisation_h
#define G4ionIonisation_h 1

#include "G4VEnergyLossSTD.hh"

class G4Material;
class G4VEmFluctuationModel;

class G4ionIonisation : public G4VEnergyLossSTD
{

public:

  G4ionIonisation(const G4String& name = "ionIoni");

  ~G4ionIonisation();

  G4bool IsApplicable(const G4ParticleDefinition& p);

  virtual G4double MinPrimaryEnergy(const G4ParticleDefinition* p,
                                    const G4Material*, G4double cut);

  virtual std::vector<G4Track*>* SecondariesAlongStep(
                             const G4Step&,
			           G4double&,
			           G4double&,
                                   G4double&);

  virtual void SecondariesPostStep(
                                   G4VEmModel*,
                             const G4MaterialCutsCouple*,
                             const G4DynamicParticle*,
                                   G4double&,
                                   G4double&);

  void SetSubCutoff(G4bool val);

  void PrintInfoDefinition();
  // Print out of the class parameters

protected:

  const G4ParticleDefinition* DefineBaseParticle(const G4ParticleDefinition* p);

  virtual G4double GetMeanFreePath(const G4Track& track,
                                         G4double previousStepSize,
                                         G4ForceCondition* condition);

  virtual G4double MaxSecondaryEnergy(const G4DynamicParticle* dynParticle);

private:

  void InitialiseProcess();

  // hide assignment operator
  G4ionIonisation & operator=(const G4ionIonisation &right);
  G4ionIonisation(const G4ionIonisation&);

  const G4ParticleDefinition* theParticle;
  const G4ParticleDefinition* theBaseParticle;
  G4VEmFluctuationModel*      flucModel;
  G4bool                      subCutoff;
};

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

inline G4bool G4ionIonisation::IsApplicable(const G4ParticleDefinition& p)
{
  return (p.GetPDGCharge() != 0.0 && p.GetParticleType() == "nucleus");
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

inline G4double G4ionIonisation::MinPrimaryEnergy(
          const G4ParticleDefinition* p, const G4Material*, G4double cut)
{
  G4double mass = p->GetPDGMass();
  G4double x = 0.5*cut/electron_mass_c2;
  //  G4double y = electron_mass_c2/mass;
  //  G4double g = x*y + sqrt((1. + x)*(1. + x*y*y));
  G4double g = sqrt(1. + x);
  return mass*(g - 1.0);
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

inline G4double G4ionIonisation::MaxSecondaryEnergy(const G4DynamicParticle* dynParticle)
{
  G4double mass  = dynParticle->GetMass();
  G4double gamma = dynParticle->GetKineticEnergy()/mass + 1.0;
  G4double ratio = electron_mass_c2/mass;
  G4double tmax = 2.0*electron_mass_c2*(gamma*gamma - 1.) /
                  (1. + 2.0*gamma*ratio + ratio*ratio);
  return tmax;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....


inline G4double G4ionIonisation::GetMeanFreePath(const G4Track& track,
                                                       G4double step,
                                                       G4ForceCondition* cond)
{
  const G4DynamicParticle* dp = track.GetDynamicParticle();
  G4double mRatio    = proton_mass_c2/dp->GetMass();
  G4double q         = dp->GetCharge()/eplus;
  G4double q_2       = q*q;
  SetMassRatio(mRatio);
  SetReduceFactor(1.0/(q_2*mRatio));
  SetChargeSquare(q_2);
  SetChargeSquareRatio(q_2);

  return G4VEnergyLossSTD::GetMeanFreePath(track, step, cond);
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

#include "G4VSubCutoffProcessor.hh"

inline std::vector<G4Track*>*  G4ionIonisation::SecondariesAlongStep(
                           const G4Step&   step,
	             	         G4double& tmax,
			         G4double& eloss,
                                 G4double& kinEnergy)
{
  std::vector<G4Track*>* newp = 0;
  if(subCutoff) {
    G4VSubCutoffProcessor* sp = SubCutoffProcessor(CurrentMaterialCutsCoupleIndex());
    if (sp) {
      G4VEmModel* model = SelectModel(kinEnergy);
      newp = sp->SampleSecondaries(step,tmax,eloss,model);
    }
  }
  return newp;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

#include "G4VEmModel.hh"

inline void G4ionIonisation::SecondariesPostStep(
                                                 G4VEmModel* model,
                                           const G4MaterialCutsCouple* couple,
                                           const G4DynamicParticle* dp,
                                                 G4double& tcut,
                                                 G4double& kinEnergy)
{
  G4DynamicParticle* delta = model->SampleSecondary(couple, dp, tcut, kinEnergy);
  if(delta) {
    aParticleChange.SetNumberOfSecondaries(1);
    aParticleChange.AddSecondary(delta);
    G4ThreeVector finalP = dp->GetMomentum();
    kinEnergy -= delta->GetKineticEnergy();
    finalP -= delta->GetMomentum();
    finalP = finalP.unit();
    aParticleChange.SetMomentumDirectionChange(finalP);
  }
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

#endif