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// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:     G4PolarizedCompton
//
// Author:        Andreas Schaelicke
//                based on code by Michel Maire / Vladimir IVANTCHENKO
// Class description
//
// modified version respecting media and beam polarization
//     using the stokes formalism
//
// Creation date: 01.05.2005
//
// Modifications:
//
// 01-01-05, include polarization description (A.Stahl)
// 01-01-05, create asymmetry table and determine interactionlength (A.Stahl)
// 01-05-05, update handling of media polarization (A.Schalicke)
// 01-05-05, update polarized differential cross section (A.Schalicke)
// 26-07-06, cross section recalculated (P.Starovoitov)
// 09-08-06, make it work under current geant4 release (A.Schalicke)
// 11-06-07, add PostStepGetPhysicalInteractionLength (A.Schalicke)
//
// -----------------------------------------------------------------------------

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#ifndef PolarizedComptonScattering_h
#define PolarizedComptonScattering_h 1

#include "globals.hh"
#include "G4VEmProcess.hh"
#include "G4Gamma.hh"

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class G4ParticleDefinition;
class G4VEmModel;
class G4MaterialCutsCouple;
class G4DynamicParticle;

class G4PolarizedComptonModel;

class G4PolarizedCompton : public G4VEmProcess

{
public:  // with description

  G4PolarizedCompton(const G4String& processName ="pol-compt",
		      G4ProcessType type = fElectromagnetic);

  virtual ~G4PolarizedCompton();

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

  // Print few lines of informations about the process: validity range,
  virtual void PrintInfo();

  void SetModel(const G4String& name);

protected:

  virtual void InitialiseProcess(const G4ParticleDefinition*);

  // added for polarization treatment of polarized media:
  virtual void BuildPhysicsTable(const G4ParticleDefinition&);
  virtual void PreparePhysicsTable(const G4ParticleDefinition&);
  void BuildAsymmetryTable(const G4ParticleDefinition& part);
  G4double ComputeAsymmetry(G4double energy,
			    const G4MaterialCutsCouple* couple,
			    const G4ParticleDefinition& particle,
			    G4double cut,
			    G4double & tAsymmetry);

  virtual G4double GetMeanFreePath(const G4Track& aTrack,     
				   G4double   previousStepSize,
				   G4ForceCondition* condition);
  virtual G4double PostStepGetPhysicalInteractionLength(
                             const G4Track& track,
                             G4double   previousStepSize,
                             G4ForceCondition* condition
                            );

  // can be removed as soon as G4PolarizationChangeForGamma is fixed!
  //  virtual G4VParticleChange* PostStepDoIt(const G4Track&, const G4Step&);

private:
  
  G4PolarizedCompton& operator=(const G4PolarizedCompton &right);
  G4PolarizedCompton(const G4PolarizedCompton& );
     
  G4bool          buildAsymmetryTable;
  G4bool          useAsymmetryTable;

  G4bool          isInitialised;
  G4VEmModel*     selectedModel;
  G4int           mType;

  // added for polarization treatment:
  G4PolarizedComptonModel* emModel;
  G4PhysicsTable* theAsymmetryTable;  // table for crosssection assymmetry
  G4ThreeVector targetPolarization;
};

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inline G4bool G4PolarizedCompton::IsApplicable(const G4ParticleDefinition& p)
{
  return (&p == G4Gamma::Gamma());
}

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#endif