G4PEEffectModel.cc

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// $Id$
//
// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:     G4PEEffectModel
//
// Author:        Vladimir Ivanchenko on base of Michel Maire code
//
// Creation date: 21.03.2005
//
// Modifications:
//
// 04.12.05 : SetProposedKineticEnergy(0.) for the killed photon (mma)
// 20.02.09 : Added initialisation of deexcitation flag and method
//            CrossSectionPerVolume instead of mfp (V.Ivanchenko)
//
// Class Description:
//
// -------------------------------------------------------------------
//
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#include "G4PEEffectModel.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4Electron.hh"
#include "G4Gamma.hh"
#include "Randomize.hh"
#include "G4DataVector.hh"
#include "G4ParticleChangeForGamma.hh"
#include "G4SauterGavrilaAngularDistribution.hh"

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using namespace std;

G4PEEffectModel::G4PEEffectModel(const G4ParticleDefinition*, 
                 const G4String& nam)
  : G4VEmModel(nam)
{
  G4cout << "### G4PEEffectModel is obsolete "
     << "and will be removed for the next release." << G4endl;

  theGamma    = G4Gamma::Gamma();
  theElectron = G4Electron::Electron();
  fminimalEnergy = 1.0*eV;
  fParticleChange = 0;

  // default generator
  SetAngularDistribution(new G4SauterGavrilaAngularDistribution());
}

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G4PEEffectModel::~G4PEEffectModel()
{}

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void G4PEEffectModel::Initialise(const G4ParticleDefinition*,
                 const G4DataVector&)
{
  // always false before the run
  SetDeexcitationFlag(false);
  if(!fParticleChange) { fParticleChange = GetParticleChangeForGamma(); }
}

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G4double G4PEEffectModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
                             G4double energy,
                             G4double Z, G4double,
                             G4double, G4double)
{
  G4double* SandiaCof = G4SandiaTable::GetSandiaCofPerAtom((G4int)Z, energy);

  G4double energy2 = energy*energy;
  G4double energy3 = energy*energy2;
  G4double energy4 = energy2*energy2;

  return SandiaCof[0]/energy  + SandiaCof[1]/energy2 +
    SandiaCof[2]/energy3 + SandiaCof[3]/energy4;
}

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G4double G4PEEffectModel::CrossSectionPerVolume(const G4Material* material,
                        const G4ParticleDefinition*,
                        G4double energy,
                        G4double, G4double)
{
  G4double* SandiaCof = 
    material->GetSandiaTable()->GetSandiaCofForMaterial(energy);
                
  G4double energy2 = energy*energy;
  G4double energy3 = energy*energy2;
  G4double energy4 = energy2*energy2;
      
  return SandiaCof[0]/energy  + SandiaCof[1]/energy2 +
    SandiaCof[2]/energy3 + SandiaCof[3]/energy4; 
}

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void G4PEEffectModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
                    const G4MaterialCutsCouple* couple,
                    const G4DynamicParticle* aDynamicPhoton,
                    G4double,
                    G4double)
{
  const G4Material* aMaterial = couple->GetMaterial();

  G4double energy = aDynamicPhoton->GetKineticEnergy();
  G4ParticleMomentum PhotonDirection = aDynamicPhoton->GetMomentumDirection();

  // select randomly one element constituing the material.
  const G4Element* anElement = SelectRandomAtom(aMaterial,theGamma,energy);
  
  //
  // Photo electron
  //

  // Select atomic shell
  G4int nShells = anElement->GetNbOfAtomicShells();
  G4int i  = 0;  
  while ((i<nShells) && (energy<anElement->GetAtomicShell(i))) { ++i; }

  G4double edep = energy;

  // no shell available
  if (i < nShells) {
  
    G4double bindingEnergy = anElement->GetAtomicShell(i);
    G4double elecKineEnergy = energy - bindingEnergy;

    if (elecKineEnergy > fminimalEnergy) {

      edep = bindingEnergy;
      G4ThreeVector elecDirection =
    GetAngularDistribution()->SampleDirection(aDynamicPhoton, 
                          elecKineEnergy,
                          i, 
                          couple->GetMaterial());

      G4DynamicParticle* aParticle = 
    new G4DynamicParticle(theElectron, elecDirection, elecKineEnergy);
      fvect->push_back(aParticle);

    } 
  }
    
  fParticleChange->SetProposedKineticEnergy(0.);
  fParticleChange->ProposeTrackStatus(fStopAndKill);
  if(edep > 0.0) {
    fParticleChange->ProposeLocalEnergyDeposit(edep);
  }
}

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