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////////////////////////////////////////////////////////////////////////
//
// File G4OpMieHG.hh
// Description: Discrete Process -- Mie Scattering of Optical Photons
// Created: 2010-07-03
// Author: Xin Qian
// Based on work from Vlasios Vasileiou
//
// This subroutine will mimic the Mie scattering based on 
// Henyey-Greenstein phase function
// Forward and backward angles are treated separately.
//
// mail: gum@triumf.ca
//
////////////////////////////////////////////////////////////////////////

#ifndef G4OpMieHG_h
#define G4OpMieHG_h 1

#include "G4VDiscreteProcess.hh"
#include "G4OpticalPhoton.hh"

class G4OpMieHG : public G4VDiscreteProcess
{

public:

  G4OpMieHG(const G4String& processName = "OpMieHG",
                     G4ProcessType type = fOptical);
  ~G4OpMieHG();

  ////////////
  // Methods
  ////////////

  G4bool IsApplicable(const G4ParticleDefinition& aParticleType);  
  // Returns true -> 'is applicable' only for an optical photon.

  G4double GetMeanFreePath(const G4Track& aTrack,
                           G4double,
                           G4ForceCondition* );
  // Return the mean free path of Mie scattering

  G4VParticleChange* PostStepDoIt(const G4Track& aTrack,
                                  const G4Step&  aStep);
  // This is the method implementing Mie scattering.

};
  

inline
G4bool G4OpMieHG::IsApplicable(const G4ParticleDefinition& aParticleType)
{
  return ( &aParticleType == G4OpticalPhoton::OpticalPhoton() );
}

#endif /* G4OpMieHG_h */