G4ePairProduction.cc

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// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:     G4ePairProduction
//
// Author:        Vladimir Ivanchenko
//
// Creation date: 17.03.2016
//
// Modifications:
//
// -------------------------------------------------------------------
//
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#include "G4ePairProduction.hh"
#include "G4SystemOfUnits.hh"
#include "G4Electron.hh"
#include "G4Positron.hh"
#include "G4VEmModel.hh"
#include "G4VEmFluctuationModel.hh"
#include "G4MuPairProductionModel.hh"
#include "G4ElementData.hh"
#include "G4EmParameters.hh"
 
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using namespace std;
 
G4ePairProduction::G4ePairProduction(const G4String& name)
  : G4VEnergyLossProcess(name),
    theParticle(nullptr),
    lowestKinEnergy(100.*MeV),
    isInitialised(false)
{
  SetProcessSubType(fPairProdByCharged);
  SetSecondaryParticle(G4Positron::Positron());
  SetIonisation(false);
}
 
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G4bool G4ePairProduction::IsApplicable(const G4ParticleDefinition& p)
{
  return (G4Electron::Electron() == &p || G4Positron::Positron() == &p);
}
 
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G4double G4ePairProduction::MinPrimaryEnergy(const G4ParticleDefinition*,
                         const G4Material*,
                         G4double)
{
  return lowestKinEnergy;
}
 
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void G4ePairProduction::InitialiseEnergyLossProcess(
                         const G4ParticleDefinition* part,
             const G4ParticleDefinition*)
{
  if (!isInitialised) {
    isInitialised = true;
 
    theParticle = part;
 
    G4MuPairProductionModel* mod = new G4MuPairProductionModel(part, "ePairProd"); 
    SetEmModel(mod);
 
    lowestKinEnergy = std::max(lowestKinEnergy, part->GetPDGMass()*8.0);
    mod->SetLowestKineticEnergy(lowestKinEnergy);
 
    G4VEmFluctuationModel* fm = nullptr;
    G4EmParameters* param = G4EmParameters::Instance();
    mod->SetLowEnergyLimit(param->MinKinEnergy());
    mod->SetHighEnergyLimit(param->MaxKinEnergy());
    AddEmModel(1, mod, fm);
  }
}
 
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void G4ePairProduction::StreamProcessInfo(std::ostream& out) const
{
  G4ElementData* ed = EmModel(0)->GetElementData();
  if(ed) {
    for(G4int Z=1; Z<93; ++Z) {
      G4Physics2DVector* pv = ed->GetElement2DData(Z);
      if(pv) {
        out << "      Sampling table " << pv->GetLengthY()
        << "x" << pv->GetLengthX() << "; from "
        << G4Exp(pv->GetY(0))/GeV << " GeV to " 
        << G4Exp(pv->GetY(pv->GetLengthY()-1))/TeV 
        << " TeV " << G4endl;
    break;
      }
    }
  }
}
 
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void G4ePairProduction::ProcessDescription(std::ostream& out) const
{
  out << "  Pair production";
  G4VEnergyLossProcess::ProcessDescription(out);
}
 
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