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// $Id: G4eBremsstrahlungModel.hh,v 1.26 2009/02/20 12:06:37 vnivanch Exp $
// GEANT4 tag $Name: geant4-09-03 $
//
// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:     G4eBremsstrahlungModel
//
// Author:        Vladimir Ivanchenko on base of Laszlo Urban code
//
// Creation date: 07.01.2002
//
// Modifications:
//
// 23-12-02 Change interface in order to move to cut per region (V.Ivanchenko)
// 24-01-03 Make models region aware (V.Ivanchenko)
// 13-02-03 Add name (V.Ivanchenko)
// 08-04-05 Major optimisation of internal interfaces (V.Ivantchenko)
// 07-02-06  public function ComputeCrossSectionPerAtom() (mma)
//
//
// Class Description:
//
// Implementation of energy loss for gamma emission by electrons and
// positrons

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

#ifndef G4eBremsstrahlungModel_h
#define G4eBremsstrahlungModel_h 1

#include "G4VEmModel.hh"

class G4Element;
class G4ParticleChangeForLoss;

class G4eBremsstrahlungModel : public G4VEmModel
{

public:

  G4eBremsstrahlungModel(const G4ParticleDefinition* p = 0, 
			 const G4String& nam = "eBrem");

  virtual ~G4eBremsstrahlungModel();

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

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

  virtual G4double ComputeDEDXPerVolume(const G4Material*,
					const G4ParticleDefinition*,
					G4double kineticEnergy,
					G4double cutEnergy);
					
  virtual G4double ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
                                                  G4double tkin, 
                                                  G4double Z,   G4double,
                                                  G4double cut,
						  G4double maxE = DBL_MAX);
  
  virtual G4double CrossSectionPerVolume(const G4Material*,
					 const G4ParticleDefinition*,
					 G4double kineticEnergy,
					 G4double cutEnergy,
					 G4double maxEnergy);

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

protected:

  const G4Element* SelectRandomAtom(const G4MaterialCutsCouple* couple);

private:

  void SetParticle(const G4ParticleDefinition* p);

  G4double ComputeBremLoss(G4double Z, G4double tkin, G4double cut);

  G4double PositronCorrFactorLoss(G4double Z, G4double tkin, G4double cut);

  G4double PositronCorrFactorSigma(G4double Z, G4double tkin, G4double cut);

  G4DataVector* ComputePartialSumSigma(const G4Material* material,
                                             G4double tkin, G4double cut);

  G4double SupressionFunction(const G4Material* material, G4double tkin,
                                    G4double gammaEnergy);

  inline G4double ScreenFunction1(G4double ScreenVariable);

  inline G4double ScreenFunction2(G4double ScreenVariable);

  // hide assignment operator
  G4eBremsstrahlungModel & operator=(const  G4eBremsstrahlungModel &right);
  G4eBremsstrahlungModel(const  G4eBremsstrahlungModel&);

protected:

  const G4ParticleDefinition* particle;
  G4ParticleDefinition*       theGamma;
  G4ParticleChangeForLoss*    fParticleChange;

  G4double minThreshold;
  G4bool   isElectron;

private:

  G4double highKinEnergy;
  G4double lowKinEnergy;
  G4double probsup;
  G4double MigdalConstant;
  G4double LPMconstant;
  G4bool   isInitialised;

  std::vector<G4DataVector*> partialSumSigma;

};

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

inline G4double G4eBremsstrahlungModel::ScreenFunction1(G4double ScreenVariable)

// compute the value of the screening function 3*PHI1 - PHI2

{
  G4double screenVal;

  if (ScreenVariable > 1.)
    screenVal = 42.24 - 8.368*std::log(ScreenVariable+0.952);
  else
    screenVal = 42.392 - ScreenVariable* (7.796 - 1.961*ScreenVariable);

  return screenVal;
} 

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

inline
G4double G4eBremsstrahlungModel::ScreenFunction2(G4double ScreenVariable)

// compute the value of the screening function 1.5*PHI1 - 0.5*PHI2

{
  G4double screenVal;

  if (ScreenVariable > 1.)
    screenVal = 42.24 - 8.368*std::log(ScreenVariable+0.952);
  else
    screenVal = 41.734 - ScreenVariable* (6.484 - 1.250*ScreenVariable);

  return screenVal;
} 

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

#endif
