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///////////////////////////////////////////////////////////////////////////
// 
// Rough model describing a gamma function distributed radiator of X-ray 
// transition radiation. XTR is considered to flux after radiator!  
// Thicknesses of plates and gas gaps are distributed according to gamma 
// distribution. x are thicknesses of plates or gas gaps:
//
// p(x) = (alpha/<x>)^alpha * x^(alpha-1) * std::exp(-alpha*x/<x>) / G(alpha)
//
// G(alpha) is Euler's gamma function.
// Plates have mean <x> = fPlateThick > 0 and power alpha = fAlphaPlate > 0 :
// Gas gaps have mean <x> = fGasThick > 0 and power alpha = fAlphaGas > 0 :
// We suppose that:
// formation zone ~ mean thickness << absorption length
// for each material and in the range 1-100 keV. This allows us to simplify
// interference effects in radiator stack (GetStackFactor method).
// 
// 
// History:
//
// 03.10.05 V. Grichine, first version 
//

#ifndef G4XTRGammaRadModel_h
#define G4XTRGammaRadModel_h 1

#include "G4VXTRenergyLoss.hh"

class G4XTRGammaRadModel : public G4VXTRenergyLoss
{
public:

  explicit G4XTRGammaRadModel (G4LogicalVolume *anEnvelope,
		      G4double,G4double,
		      G4Material*,G4Material*,
		      G4double,G4double,G4int,
		      const G4String & processName = "XTRgammaRadiator"   );
  virtual ~G4XTRGammaRadModel ();

  // Pure virtual function from base class

  G4double GetStackFactor(G4double energy, G4double gamma, 
                          G4double varAngle) override;

private:

  //  G4double fAlphaPlate, fAlphaGas ;
};

#endif
