G4XTRTransparentRegRadModel.cc

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#include "G4XTRTransparentRegRadModel.hh"
 
#include "G4PhysicalConstants.hh"
 
////////////////////////////////////////////////////////////////////////////
// Constructor, destructor
G4XTRTransparentRegRadModel::G4XTRTransparentRegRadModel(
  G4LogicalVolume* anEnvelope, G4Material* foilMat, G4Material* gasMat,
  G4double a, G4double b, G4int n, const G4String& processName)
  : G4VXTRenergyLoss(anEnvelope, foilMat, gasMat, a, b, n, processName)
{
  G4cout << "Regular transparent X-ray TR  radiator EM process is called"
         << G4endl;
 
  fExitFlux   = true;
  fAlphaPlate = 10000;
  fAlphaGas   = 1000;
}
 
///////////////////////////////////////////////////////////////////////////
G4XTRTransparentRegRadModel::~G4XTRTransparentRegRadModel() = default;
 
///////////////////////////////////////////////////////////////////////////
void G4XTRTransparentRegRadModel::ProcessDescription(std::ostream& out) const
{
  out << "Process describing radiator of X-ray transition radiation.\n";
}
 
///////////////////////////////////////////////////////////////////////////
G4double G4XTRTransparentRegRadModel::SpectralXTRdEdx(G4double energy)
{
  static constexpr G4double cofPHC = 4. * pi * hbarc;
  G4double result, sum = 0., tmp, cof1, cof2, cofMin, aMa, bMb, sigma;
  G4int k, kMax, kMin;
 
  aMa = GetPlateLinearPhotoAbs(energy);
  bMb = GetGasLinearPhotoAbs(energy);
 
  if(fCompton)
  {
    aMa += GetPlateCompton(energy);
    bMb += GetGasCompton(energy);
  }
  aMa *= fPlateThick;
  bMb *= fGasThick;
 
  sigma = aMa + bMb;
 
  tmp  = (fSigma1 - fSigma2) / cofPHC / energy;
  cof1 = fPlateThick * tmp;
  cof2 = fGasThick * tmp;
 
  cofMin = energy * (fPlateThick + fGasThick) / fGamma / fGamma;
  cofMin += (fPlateThick * fSigma1 + fGasThick * fSigma2) / energy;
  cofMin /= cofPHC;
 
  kMin = G4int(cofMin);
  if(cofMin > kMin)
    kMin++;
 
  kMax = kMin + 19;
 
  for(k = kMin; k <= kMax; k++)
  {
    tmp    = pi * fPlateThick * (k + cof2) / (fPlateThick + fGasThick);
    result = (k - cof1) * (k - cof1) * (k + cof2) * (k + cof2);
 
    if(k == kMin && kMin == G4int(cofMin))
    {
      sum +=
        0.5 * std::sin(tmp) * std::sin(tmp) * std::abs(k - cofMin) / result;
    }
    else
    {
      sum += std::sin(tmp) * std::sin(tmp) * std::abs(k - cofMin) / result;
    }
  }
  result = 4. * (cof1 + cof2) * (cof1 + cof2) * sum / energy;
  result *= (1. - std::exp(-fPlateNumber * sigma)) / (1. - std::exp(-sigma));
  return result;
}
 
///////////////////////////////////////////////////////////////////////////
// Approximation for radiator interference factor for the case of
// fully Regular radiator. The plate and gas gap thicknesses are fixed.
// 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 corresponding material.
G4double G4XTRTransparentRegRadModel::GetStackFactor(G4double energy,
                                                     G4double gamma,
                                                     G4double varAngle)
{
  G4double aZa   = fPlateThick / GetPlateFormationZone(energy, gamma, varAngle);
  G4double bZb   = fGasThick / GetGasFormationZone(energy, gamma, varAngle);
  G4double aMa   = fPlateThick * GetPlateLinearPhotoAbs(energy);
  G4double bMb   = fGasThick * GetGasLinearPhotoAbs(energy);
  G4double sigma = aMa * fPlateThick + bMb * fGasThick;
  G4double Qa    = std::exp(-0.5 * aMa);
  G4double Qb    = std::exp(-0.5 * bMb);
  G4double Q     = Qa * Qb;
 
  G4complex Ha(Qa * std::cos(aZa), -Qa * std::sin(aZa));
  G4complex Hb(Qb * std::cos(bZb), -Qb * std::sin(bZb));
  G4complex H  = Ha * Hb;
  G4complex Hs = conj(H);
  G4double D =
    1.0 / ((1. - Q) * (1. - Q) +
           4. * Q * std::sin(0.5 * (aZa + bZb)) * std::sin(0.5 * (aZa + bZb)));
  G4complex F1 =
    (1.0 - Ha) * (1.0 - Hb) * (1.0 - Hs) * G4double(fPlateNumber) * D;
  G4complex F2 = (1.0 - Ha) * (1.0 - Ha) * Hb * (1.0 - Hs) * (1.0 - Hs) *
                 (1.0 - std::exp(-0.5 * fPlateNumber * sigma)) * D * D;
  G4complex R = (F1 + F2) * OneInterfaceXTRdEdx(energy, gamma, varAngle);
  return 2.0 * std::real(R);
}