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// $Id: G4BetheBlochModel.hh,v 1.5 2005/05/12 11:06:42 vnivanch Exp $
// GEANT4 tag $Name: geant4-07-01 $
//
// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:     G4BetheBlochModel
//
// Author:        Vladimir Ivanchenko on base of Laszlo Urban code
//
// Creation date: 03.01.2002
//
// Modifications:
//
// 23-12-02 V.Ivanchenko change interface in order to moveto cut per region
// 24-01-03 Make models region aware (V.Ivanchenko)
// 13-02-03 Add name (V.Ivanchenko)
// 12-11-03 Fix for GenericIons (V.Ivanchenko)
// 24-03-05 Add G4EmCorrections (V.Ivanchenko)
// 11-04-05 Major optimisation of internal interfaces (V.Ivantchenko)
// 11-04-04 Move MaxSecondaryEnergy to models (V.Ivanchenko)
//
// Class Description:
//
// Implementation of Bethe-Bloch model of energy loss and
// delta-electron production by heavy charged particles

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

#ifndef G4BetheBlochModel_h
#define G4BetheBlochModel_h 1

#include "G4VEmModel.hh"

class G4EmCorrections;
class G4ParticleChangeForLoss;

class G4BetheBlochModel : public G4VEmModel
{

public:

  G4BetheBlochModel(const G4ParticleDefinition* p = 0, const G4String& nam = "BetheBloch");

  virtual ~G4BetheBlochModel();

  virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&);

  G4double MinEnergyCut(const G4ParticleDefinition*,
			const G4MaterialCutsCouple*);

  virtual G4double ComputeDEDXPerVolume(const G4Material*,
					const G4ParticleDefinition*,
					G4double kineticEnergy,
					G4double cutEnergy);

  virtual G4double CrossSectionPerVolume(const G4Material*,
					 const G4ParticleDefinition*,
					 G4double kineticEnergy,
					 G4double cutEnergy,
					 G4double maxEnergy);

  virtual std::vector<G4DynamicParticle*>* SampleSecondaries(
                                const G4MaterialCutsCouple*,
                                const G4DynamicParticle*,
                                      G4double tmin,
                                      G4double maxEnergy);

protected:

  G4double MaxSecondaryEnergy(const G4ParticleDefinition*,
			      G4double kinEnergy);

private:

  void SetParticle(const G4ParticleDefinition* p);

  // hide assignment operator
  G4BetheBlochModel & operator=(const  G4BetheBlochModel &right);
  G4BetheBlochModel(const  G4BetheBlochModel&);

  const G4ParticleDefinition* particle;
  G4ParticleDefinition*       theElectron;
  G4EmCorrections*            corr;
  G4ParticleChangeForLoss*    fParticleChange;

  G4double mass;
  G4double tlimit;
  G4double spin;
  G4double chargeSquare;
  G4double ratio;
  G4double twoln10;
  G4double bg2lim;
  G4double taulim;
  G4bool   isIon;
};

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

inline G4double G4BetheBlochModel::MaxSecondaryEnergy(
          const G4ParticleDefinition* pd,
                G4double kinEnergy) 
{
  if(isIon) SetParticle(pd);
  G4double tau  = kinEnergy/mass;
  G4double tmax = 2.0*electron_mass_c2*tau*(tau + 2.) /
                  (1. + 2.0*(tau + 1.)*ratio + ratio*ratio);
  return std::min(tmax,tlimit);
}

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

inline void G4BetheBlochModel::SetParticle(const G4ParticleDefinition* p)
{
  if(particle != p) {
    particle = p;
    mass = particle->GetPDGMass();
    spin = particle->GetPDGSpin();
    G4double q = particle->GetPDGCharge()/eplus;
    chargeSquare = q*q;
    ratio = electron_mass_c2/mass;
    tlimit = 51.2*GeV*std::pow(proton_mass_c2/mass,0.66667);
  }
}

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

#endif