G4MuPairProductionModel.hh

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// $Id$
//
// -------------------------------------------------------------------
//
// 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
//

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

#ifndef G4MuPairProductionModel_h
#define G4MuPairProductionModel_h 1

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

class G4Element;
class G4ParticleChangeForLoss;
class G4ParticleChangeForGamma;

class G4MuPairProductionModel : public G4VEmModel
{
public:

  G4MuPairProductionModel(const G4ParticleDefinition* p = 0,
                          const G4String& nam = "muPairProd");

  virtual ~G4MuPairProductionModel();

  virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&);
            
  virtual G4double ComputeCrossSectionPerAtom(
                 const G4ParticleDefinition*,
                 G4double kineticEnergy,
                 G4double Z, G4double A,
                 G4double cutEnergy,
                 G4double maxEnergy);
                 
  virtual G4double ComputeDEDXPerVolume(const G4Material*,
                                const G4ParticleDefinition*,
                                G4double kineticEnergy,
                                G4double cutEnergy);

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

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

  inline void SetLowestKineticEnergy(G4double e);

  inline void SetParticle(const G4ParticleDefinition*);

protected:

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

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

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

  virtual G4double MaxSecondaryEnergy(const G4ParticleDefinition*,
                      G4double kineticEnergy);

  inline void SetCurrentElement(G4double Z);

private:

  const G4Element* SelectRandomAtom(G4double kinEnergy, 
                    G4double dt, 
                    G4int it,
                    const G4MaterialCutsCouple* couple, 
                    G4double tmin);

  void MakeSamplingTables();

  inline G4double InterpolatedIntegralCrossSection(
             G4double dt, G4double dz, G4int iz,
             G4int it, G4int iy, G4double z);

  // hide assignment operator
  G4MuPairProductionModel & operator=(const  G4MuPairProductionModel &right);
  G4MuPairProductionModel(const  G4MuPairProductionModel&);

protected:

  const G4ParticleDefinition* particle;
  G4NistManager*              nist;

  G4double factorForCross;
  G4double sqrte;
  G4double particleMass;
  G4double currentZ;
  G4double z13;
  G4double z23;
  G4double lnZ;

  static G4double xgi[8],wgi[8];

private:

  G4ParticleDefinition*       theElectron;
  G4ParticleDefinition*       thePositron;
  G4ParticleChangeForLoss*    fParticleChange;

  G4double minPairEnergy;
  G4double lowestKinEnergy;

  // tables for sampling
  G4int nzdat;
  G4int ntdat;
  G4int nbiny;
  size_t nmaxElements;
  static G4double zdat[5], adat[5], tdat[8];
  G4double ya[1001], proba[5][8][1001];

  G4double ymin;
  G4double ymax;
  G4double dy;

  G4bool  samplingTablesAreFilled;
  std::vector<G4double> partialSum;
};

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

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

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

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

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

inline void G4MuPairProductionModel::SetCurrentElement(G4double Z)
{
  if(Z != currentZ) {
    currentZ = Z;
    G4int iz = G4int(Z);
    z13 = nist->GetZ13(iz);
    z23 = z13*z13;
    lnZ = nist->GetLOGZ(iz);
  }
}

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

inline G4double G4MuPairProductionModel::InterpolatedIntegralCrossSection(
            G4double dt, G4double dz,
                G4int iz, G4int it, G4int iy, G4double z)
{
  G4double fac =  1./(zdat[iz]  *(zdat[iz]  +1.));
  G4double fac1 = 1./(zdat[iz-1]*(zdat[iz-1]+1.));
  G4double f0 = fac1*proba[iz-1][it-1][iy] + 
                (fac*proba[iz][it-1][iy]-fac1*proba[iz-1][it-1][iy])*dz;
  G4double f1 = fac1*proba[iz-1][it  ][iy] + 
                (fac*proba[iz][it  ][iy]-fac1*proba[iz-1][it  ][iy])*dz;
  return (f0 + (f1-f0)*dt)*z*(z+1.);
}

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

#endif