G4RToEConvForProton.cc

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//
// G4RToEConvForProton class implementation
//
// Author: H.Kurashige, 05 October 2002 - First implementation
// --------------------------------------------------------------------
 
#include "G4RToEConvForProton.hh"
#include "G4ParticleTable.hh"
#include "G4Material.hh"
#include "G4PhysicsLogVector.hh"
 
#include "G4ios.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
 
// --------------------------------------------------------------------
G4RToEConvForProton::G4RToEConvForProton() 
  : G4VRangeToEnergyConverter()
{    
  theParticle = G4ParticleTable::GetParticleTable()->FindParticle("proton");
  if (theParticle == nullptr)
  {
#ifdef G4VERBOSE
    if (GetVerboseLevel()>0)
    {
      G4cout << "G4RToEConvForProton::G4RToEConvForProton() - ";
      G4cout << "Proton is not defined !!" << G4endl;
    }
#endif
  }
  else
  {
    Mass = theParticle->GetPDGMass();
  } 
}
 
// --------------------------------------------------------------------
G4RToEConvForProton::~G4RToEConvForProton()
{ 
}
 
// --------------------------------------------------------------------
G4double G4RToEConvForProton::Convert(G4double rangeCut, const G4Material* )
{
  // Simple formula - range = Ekin/(100*keV)*(1*mm);
 
  return (rangeCut/(1.0*mm)) * (100.0*keV); 
}
 
// **********************************************************************
// ************************* ComputeLoss ********************************
// **********************************************************************
G4double G4RToEConvForProton::ComputeLoss(G4double AtomicNumber,
                                          G4double KineticEnergy) 
{
  //  calculate dE/dx
  const G4double z2Particle = 1.0;
 
  if( std::fabs(AtomicNumber-Z)>0.1 )
  {
    // recalculate constants
    Z = AtomicNumber;
    G4double Z13 = std::exp(std::log(Z)/3.);
    tau0 = 0.1*Z13*MeV/proton_mass_c2;
    taum = 0.035*Z13*MeV/proton_mass_c2;
    taul = 2.*MeV/proton_mass_c2;
    ionpot = 1.6e-5*MeV*std::exp(0.9*std::log(Z));
    cc = (taul+1.)*(taul+1.)*std::log(2.*electron_mass_c2*taul*(taul+2.)/ionpot)
       / (taul*(taul+2.))-1.;
    cc = 2.*twopi_mc2_rcl2*Z*cc*std::sqrt(taul);
    ca = cc/((1.-0.5*std::sqrt(tau0/taum))*tau0);
    cba = -0.5/std::sqrt(taum);
  }
 
  G4double tau = KineticEnergy/Mass;
  G4double dEdx;
  if ( tau <= tau0 )
  {
    dEdx = ca*(std::sqrt(tau)+cba*tau);
  }
  else
  {
    if( tau <= taul )
    {
      dEdx = cc/std::sqrt(tau);
    }
    else
    {
      dEdx = (tau+1.)*(tau+1.)
           * std::log(2.*electron_mass_c2*tau*(tau+2.)/ionpot)
           / (tau*(tau+2.))-1.;
      dEdx = 2.*twopi_mc2_rcl2*Z*dEdx;
    }
  }
  return dEdx*z2Particle ;
}
 
// **********************************************************************
// ************************* Reset       ********************************
// **********************************************************************
void G4RToEConvForProton::Reset()
{
  // do nothing because loss tables and range vectors are not used 
 
  return;
}