G4GEMCoulombBarrierHE.cc

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// $Id$
//
// Hadronic Process: Nuclear De-excitations
// by V. Lara (Dec 1999)

#include "G4GEMCoulombBarrierHE.hh"
#include "G4HadronicException.hh"
#include "G4Pow.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"

G4GEMCoulombBarrierHE::G4GEMCoulombBarrierHE(G4int anA, G4int aZ) :
  G4VCoulombBarrier(anA,aZ) 
{}

G4GEMCoulombBarrierHE::~G4GEMCoulombBarrierHE() 
{}

G4double G4GEMCoulombBarrierHE::GetCoulombBarrier(G4int ARes, G4int ZRes, G4double U) const 
  // Calculation of Coulomb potential energy (barrier) for outgoing fragment
{
  G4double Barrier = 0.0;
  if (ZRes > ARes || ARes < 1) {
    G4cout << "G4GEMCoulombBarrierHE::GetCoulombBarrier: "
           << "Wrong values for "
           << "residual nucleus A = " << ARes << " "
           << "and residual nucleus Z = " << ZRes << G4endl;
    throw G4HadronicException(__FILE__, __LINE__,"FATAL error");
  }
  if (GetZ() == 0) {
    Barrier = 0.0;   // If there is no charge there is neither barrier
  } else {
    G4double CompoundRadius = CalcCompoundRadius(ARes);
    Barrier = ( elm_coupling * GetZ() * ZRes)/(CompoundRadius+3.75*fermi);
    
    // Barrier penetration coeficient
    //    G4double K = BarrierPenetrationFactor(ZRes);
    //    Barrier *= K;
    
    Barrier /= (1.0 + std::sqrt(U/static_cast<G4double>(2*ARes)));
  }
  return Barrier;
}


G4double G4GEMCoulombBarrierHE::CalcCompoundRadius(G4int ARes) const
{
  G4Pow* g4pow = G4Pow::GetInstance();
  G4double AresOneThird = g4pow->Z13(ARes);
  G4double AejectOneThird = g4pow->Z13(GetA());

  G4double Result = 1.12*(AresOneThird + AejectOneThird) - 
    0.86*(AresOneThird+AejectOneThird)/(AresOneThird*AejectOneThird);

  return Result*fermi;
}

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