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// $Id$
// GEANT4 tag $Name:  $
//
// ------------------------------------------------------------
//      GEANT 4 class header file
//      CERN Geneva Switzerland
//

// --------- G4LowEnergyPolarizedCompton class -----
//
//           by G.Depaola & F.Longo (21 may 2001)
// 24 May 2001 - MGP      Modified to inherit from G4VDiscreteProcess
// 25 May 2001 - MGP      Added protections to avoid crashes
//
// 17 October 2001 - F.Longo  Major revision according to design iteration
//
// 21 February 2002 - F.Longo Revisions with A.Zoglauer and G.Depaola
//                            - better description of parallelism
//                            - system of ref change method improved
//
//
// Class description:
// Low Energy electromagnetic process, Polarised Compton scattering
// Further documentation available from http://www.ge.infn.it/geant4/lowE

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

#ifndef G4RDLOWENERGYPOLARIZEDCOMPTON_H
#define G4RDLOWENERGYPOLARIZEDCOMPTON_H 1

#include "globals.hh"
#include "G4VDiscreteProcess.hh"

// Doppler Broadening

#include "G4RDShellData.hh"
#include "G4RDDopplerProfile.hh"


class G4Track;
class G4Step;
class G4ParticleDefinition;
class G4VParticleChange;
class G4RDVEMDataSet;
class G4RDVCrossSectionHandler;
class G4RDVRangeTest;

class G4LowEnergyPolarizedCompton : public  G4VDiscreteProcess
{  
public:  
  
  G4LowEnergyPolarizedCompton(const G4String& processName = "polarLowEnCompt");
  
  ~G4LowEnergyPolarizedCompton();

  G4bool IsApplicable(const G4ParticleDefinition& definition);
  
  void BuildPhysicsTable(const G4ParticleDefinition& photon);
  G4VParticleChange* PostStepDoIt(const G4Track& aTrack, const G4Step& aStep);
  
  
  // For testing purpose only
  G4double DumpMeanFreePath(const G4Track& aTrack, 
			    G4double previousStepSize, 
			    G4ForceCondition* condition) 
  { return GetMeanFreePath(aTrack, previousStepSize, condition); }
  
  
protected:
  
  G4double GetMeanFreePath(const G4Track& aTrack, 
			   G4double previousStepSize, 
			   G4ForceCondition* condition);
private:

  // Hide copy constructor and assignment operator as private 

  G4LowEnergyPolarizedCompton& operator=(const G4LowEnergyPolarizedCompton& 
					 right);
  G4LowEnergyPolarizedCompton(const G4LowEnergyPolarizedCompton& );
  
  G4double lowEnergyLimit;  // low energy limit  applied to the process
  G4double highEnergyLimit; // high energy limit applied to the process
  
  G4RDVEMDataSet* meanFreePathTable;
  G4RDVEMDataSet* scatterFunctionData;

  G4RDVCrossSectionHandler* crossSectionHandler;
  G4RDVRangeTest* rangeTest;

  const G4double intrinsicLowEnergyLimit; // intrinsic validity range
  const G4double intrinsicHighEnergyLimit;

  // specific methods for polarization 
  
  G4ThreeVector GetRandomPolarization(G4ThreeVector& direction0); // Random Polarization
  G4ThreeVector GetPerpendicularPolarization(const G4ThreeVector& direction0, const G4ThreeVector& polarization0) const;
  
  G4ThreeVector SetPerpendicularVector(G4ThreeVector& a); // temporary
  G4ThreeVector SetNewPolarization(G4double epsilon, G4double sinSqrTheta, 
				   G4double phi, G4double cosTheta);
  G4double SetPhi(G4double, G4double);
  
  void SystemOfRefChange(G4ThreeVector& direction0, G4ThreeVector& direction1, 
			 G4ThreeVector& polarization0, G4ThreeVector& polarization1);
  
  // Doppler Broadening
 
  G4RDShellData shellData;
  G4RDDopplerProfile profileData;


};

#endif
 








