G4GammaXTRadiator.cc

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// $Id$
//

#include <complex>

#include "G4GammaXTRadiator.hh"
#include "Randomize.hh"

#include "G4Gamma.hh"

//
// Constructor, destructor

G4GammaXTRadiator::G4GammaXTRadiator(G4LogicalVolume* anEnvelope, 
                     G4double alphaPlate,
                     G4double alphaGas,
                                     G4Material* foilMat,G4Material* gasMat, 
                                     G4double a, G4double b, G4int n,
                                     const G4String& processName) :
  G4VXTRenergyLoss(anEnvelope,foilMat,gasMat,a,b,n,processName)
{
  G4cout<<"Gammma distributed X-ray TR radiator model is called"<<G4endl ;

  // Build energy and angular integral spectra of X-ray TR photons from
  // a radiator

  fAlphaPlate = alphaPlate ;
  fAlphaGas   = alphaGas   ;
  G4cout<<"fAlphaPlate = "<<fAlphaPlate<<" ; fAlphaGas = "<<fAlphaGas<<G4endl ;

  // BuildTable() ;
}


G4GammaXTRadiator::~G4GammaXTRadiator()
{
  ;
}



//
// Rough approximation for radiator interference factor for the case of
// fully GamDistr radiator. The plate and gas gap thicknesses are distributed 
// according to exponent. The mean values of the plate and gas gap thicknesses 
// are supposed to be about XTR formation zones but much less than 
// mean absorption length of XTR photons in coresponding material.

G4double 
G4GammaXTRadiator::GetStackFactor( G4double energy, 
                                         G4double gamma, G4double varAngle )
{
  G4double result, Za, Zb, Ma, Mb ;
  
  Za = GetPlateFormationZone(energy,gamma,varAngle) ;
  Zb = GetGasFormationZone(energy,gamma,varAngle) ;

  Ma = GetPlateLinearPhotoAbs(energy) ;
  Mb = GetGasLinearPhotoAbs(energy) ;


  G4complex Ca(1.0+0.5*fPlateThick*Ma/fAlphaPlate,fPlateThick/Za/fAlphaPlate) ; 
  G4complex Cb(1.0+0.5*fGasThick*Mb/fAlphaGas,fGasThick/Zb/fAlphaGas) ; 

  G4complex Ha = std::pow(Ca,-fAlphaPlate) ;  
  G4complex Hb = std::pow(Cb,-fAlphaGas) ;
  G4complex H  = Ha*Hb ;

  G4complex F1 =   (1.0 - Ha)*(1.0 - Hb )/(1.0 - H)
                 * G4double(fPlateNumber) ;

  G4complex F2 =   (1.0-Ha)*(1.0-Ha)*Hb/(1.0-H)/(1.0-H)
                 * (1.0 - std::pow(H,fPlateNumber)) ;

  G4complex R  = (F1 + F2)*OneInterfaceXTRdEdx(energy,gamma,varAngle) ;

  result       = 2.0*std::real(R) ;
  
  return      result ;
}


//
//