/home/cern/BDSIM_new/include/BDSGammaConversionToMuons.hh

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// $Id: BDSGammaConversionToMuons.hh,v 1.1 2006/04/09 17:59:43 agapov Exp $
// GEANT4 tag $Name:  $
//
//         ------------ G4GammaConversionToMuons physics process ------
//         by H.Burkhardt, S. Kelner and R. Kokoulin, April 2002
// -----------------------------------------------------------------------------
//
// 05-08-04: suppression of .icc file (mma)
// 13-08-04, public ComputeCrossSectionPerAtom() and ComputeMeanFreePath() (mma) 
//
// class description
//
// gamma ---> mu+ mu-
// inherit from G4VDiscreteProcess
//

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#ifndef BDSGammaConversionToMuons_h
#define BDSGammaConversionToMuons_h 1

#include "G4ios.hh"
#include "globals.hh"
#include "Randomize.hh"
#include "G4VDiscreteProcess.hh"
#include "G4PhysicsTable.hh"
#include "G4PhysicsLogVector.hh"
#include "G4Element.hh"
#include "G4Gamma.hh"
#include "G4Electron.hh"
#include "G4Positron.hh"
#include "G4Step.hh"

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class BDSGammaConversionToMuons : public G4VDiscreteProcess

{
  public:  // with description

     BDSGammaConversionToMuons(const G4String& processName ="BDS-GammaToMuPair",
                                    G4ProcessType type = fElectromagnetic);

    ~BDSGammaConversionToMuons();

     G4bool IsApplicable(const G4ParticleDefinition&);
       // true for Gamma only.

     void BuildPhysicsTable(const G4ParticleDefinition&);
       // here dummy, the total cross section parametrization is used rather
       // than tables,  just calling PrintInfoDefinition

     void PrintInfoDefinition();
       // Print few lines of informations about the process: validity range,
       // origine ..etc..
       // Invoked by BuildThePhysicsTable().

     void SetCrossSecFactor(G4double fac);
       // Set the factor to artificially increase the crossSection (default 1)

     G4double GetCrossSecFactor() { return CrossSecFactor;}
       // Get the factor to artificially increase the cross section

     G4double GetMeanFreePath(const G4Track& aTrack,
                              G4double previousStepSize,
                              G4ForceCondition* condition);
       // It returns the MeanFreePath of the process for the current track :
       // (energy, material)
       // The previousStepSize and G4ForceCondition* are not used.
       // This function overloads a virtual function of the base class.
       // It is invoked by the ProcessManager of the Particle.

     G4double GetCrossSectionPerAtom(const G4DynamicParticle* aDynamicGamma,
                                           G4Element*         anElement);
       // It returns the total CrossSectionPerAtom of the process,
       // for the current DynamicGamma (energy), in anElement.

     G4VParticleChange* PostStepDoIt(const G4Track& aTrack,
                                    const G4Step& aStep);
       // It computes the final state of the process (at end of step),
       // returned as a ParticleChange object.
       // This function overloads a virtual function of the base class.
       // It is invoked by the ProcessManager of the Particle.

     virtual
     G4double ComputeCrossSectionPerAtom(G4double GammaEnergy,
                                         G4double AtomicZ,G4double AtomicA);

     G4double ComputeMeanFreePath (G4double GammaEnergy,
                                   G4Material* aMaterial);

  private:

     G4Element* SelectRandomAtom(const G4DynamicParticle* aDynamicGamma,
                                 G4Material* aMaterial);

  private:

     // hide assignment operator as private
     BDSGammaConversionToMuons& operator=(const BDSGammaConversionToMuons &right);
     BDSGammaConversionToMuons(const BDSGammaConversionToMuons& );

  private:

     G4double LowestEnergyLimit ;     // low  energy limit of the tables
     G4double HighestEnergyLimit ;    // high energy limit of the tables

     G4double fminimalEnergy;         // minimalEnergy of produced particles

     G4double MeanFreePath;           // actual MeanFreePath (current medium)
     G4double CrossSecFactor;         // factor to artificially increase
                                      // the cross section

};

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#endif

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