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// $Id: G4PolarizedPairProductionCrossSection.hh,v 1.3 2007/11/01 17:32:34 schaelic Exp $
// GEANT4 tag $Name: geant4-09-02-ref-02 $
//
// GEANT4 Class file
//
//
// File name:     G4PolarizedPairProductionCrossSection
//
// Author:        Karim Laihem
//
// Creation date: 15.05.2005
//
// Modifications:
// 20-08-06  updated interface to geant4.8.1 (A.Schaelicke)
// 15-10-07 introduced a more general framework for cross sections (AS)
//
// Class Description:
//   determine the  polarization of the final state 
//   in a Bremsstrahlung scattering process employing the differential 
//   cross section by Olsen and Maximon
//
#ifndef G4PolarizedPairProductionCrossSection_h
#define G4PolarizedPairProductionCrossSection_h 1

#include "G4StokesVector.hh"
#include "G4VPolarizedCrossSection.hh"


class G4PolarizedPairProductionCrossSection : public G4VPolarizedCrossSection
{
 public:
  G4PolarizedPairProductionCrossSection();
  virtual void Initialize(G4double eps, G4double X, G4double phi,
			  const G4StokesVector & p0,
			  const G4StokesVector & p1,
			  G4int flag=0); 
  virtual G4double XSection(const G4StokesVector & pol2,
			    const G4StokesVector & pol3); 

  // return expected mean polarisation
  G4StokesVector GetPol2();  // electron/positron
  G4StokesVector GetPol3();  // photon
 private:

  G4StokesVector  theFinalElectronPolarization;
  G4StokesVector  theFinalPositronPolarization;

  void InitializeMe();

  static G4bool scrnInitialized;
  static G4double SCRN [3][20];  // screening function lookup table;
};

#endif
