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// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:     G4MuPairProductionModel
//
// Author:        Vladimir Ivanchenko on base of Laszlo Urban code
//
// Creation date: 18.05.2002
//
// Modifications:
//
// 23-12-02 Change interface in order to move to cut per region (V.Ivanchenko)
// 27-01-03 Make models region aware (V.Ivanchenko)
// 13-02-03 Add name (V.Ivanchenko)
// 10-02-04 Update parameterisation using R.Kokoulin model (V.Ivanchenko)
// 10-02-04 Add lowestKinEnergy (V.Ivanchenko)
// 13-02-06 Add ComputeCrossSectionPerAtom (mma)
// 12-05-06 Add parameter to SelectRandomAtom (A.Bogdanov) 
// 11-10-07 Add ignoreCut flag (V.Ivanchenko) 
// 28-02-08 Reorganized protected methods and members (V.Ivanchenko) 
//
// Class Description:
//
// Implementation of e+e- pair production by muons
// A.G. Bogdanov et al., IEEE Trans. Nuc. Sci., Vol.53, No.2, 2006
// Base class for all pair production models for muons and hadrons.
//
// -------------------------------------------------------------------
//

#ifndef G4MuPairProductionModel_h
#define G4MuPairProductionModel_h 1

#include "G4VEmModel.hh"
#include "G4NistManager.hh"
#include "G4ElementData.hh"
#include "G4Physics2DVector.hh"
#include <vector>

class G4Element;
class G4ParticleChangeForLoss;
class G4ParticleChangeForGamma;

class G4MuPairProductionModel : public G4VEmModel
{
public:

  explicit G4MuPairProductionModel(const G4ParticleDefinition* p = nullptr,
                                   const G4String& nam = "muPairProd");

  ~G4MuPairProductionModel() override = default;

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

  void InitialiseLocal(const G4ParticleDefinition*,
                       G4VEmModel* masterModel) override;
			
  G4double ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
				      G4double kineticEnergy,
				      G4double Z, G4double A,
				      G4double cutEnergy,
				      G4double maxEnergy) override;
				 
  G4double ComputeDEDXPerVolume(const G4Material*,
                                const G4ParticleDefinition*,
                                G4double kineticEnergy,
                                G4double cutEnergy) override;

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

  G4double MinPrimaryEnergy(const G4Material*,
                            const G4ParticleDefinition*,
                            G4double) override;

  virtual G4double 
  ComputeDMicroscopicCrossSection(G4double tkin, G4double Z,
				  G4double pairEnergy);

  inline void SetLowestKineticEnergy(G4double e);

  inline void SetParticle(const G4ParticleDefinition*);

  // hide assignment operator and copy constructor
  G4MuPairProductionModel & operator=
  (const G4MuPairProductionModel &right) = delete;
  G4MuPairProductionModel(const  G4MuPairProductionModel&) = delete;

protected:

  G4double ComputMuPairLoss(G4double Z, G4double tkin, G4double cut,
                            G4double tmax);

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

  G4double FindScaledEnergy(G4int Z, G4double rand, G4double logTkin,
			    G4double yymin, G4double yymax); 

  inline G4double MaxSecondaryEnergyForElement(G4double kineticEnergy,
					       G4double Z);

  void MakeSamplingTables();

  void StoreTables() const;

  G4bool RetrieveTables();

  virtual void DataCorrupted(G4int Z, G4double logTkin) const;

  G4ParticleChangeForLoss* fParticleChange = nullptr;
  const G4ParticleDefinition* particle = nullptr;
  G4NistManager* nist = nullptr;

  G4double factorForCross;
  G4double sqrte;
  G4double particleMass = 0.0;
  G4double z13 = 0.0;
  G4double z23 = 0.0;
  G4double lnZ = 0.0;

  G4double minPairEnergy;
  G4double lowestKinEnergy;

  G4double emin;
  G4double emax;
  G4double ymin = -5.0;
  G4double dy = 0.005;

  G4int currentZ = 0;
  G4int nYBinPerDecade = 4;
  std::size_t nbiny = 1000;
  std::size_t nbine = 0;

  G4bool fTableToFile = false;

  // static members
  static const G4int NZDATPAIR = 5;
  static const G4int NINTPAIR = 8;
  static const G4int ZDATPAIR[NZDATPAIR];
  static const G4double xgi[NINTPAIR];
  static const G4double wgi[NINTPAIR];

private:

  G4ParticleDefinition* theElectron;
  G4ParticleDefinition* thePositron;
  G4String dataName{""};
};

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

inline void G4MuPairProductionModel::SetLowestKineticEnergy(G4double e) 
{
  lowestKinEnergy = e;
}

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

inline
void G4MuPairProductionModel::SetParticle(const G4ParticleDefinition* p)
{
  if(nullptr == particle) {
    particle = p;
    particleMass = particle->GetPDGMass();
  }
}

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

inline G4double 
G4MuPairProductionModel::MaxSecondaryEnergyForElement(G4double kineticEnergy,
						      G4double ZZ)
{
  G4int Z = G4lrint(ZZ);
  if(Z != currentZ) {
    currentZ = Z;
    z13 = nist->GetZ13(Z);
    z23 = z13*z13;
    lnZ = nist->GetLOGZ(Z);
  }
  return kineticEnergy + particleMass*(1.0 - 0.75*sqrte*z13);
}

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

#endif