G4LivermoreComptonModel Class Reference

#include <G4LivermoreComptonModel.hh>

Inheritance diagram for G4LivermoreComptonModel:

Public Member Functions
	G4LivermoreComptonModel (const G4ParticleDefinition *p=0, const G4String &nam="LivermoreCompton")
virtual	~G4LivermoreComptonModel ()
virtual void	Initialise (const G4ParticleDefinition *, const G4DataVector &)
virtual void	InitialiseLocal (const G4ParticleDefinition *, G4VEmModel *masterModel)
virtual void	InitialiseForElement (const G4ParticleDefinition *, G4int Z)
virtual G4double	ComputeCrossSectionPerAtom (const G4ParticleDefinition *, G4double kinEnergy, G4double Z, G4double A=0, G4double cut=0, G4double emax=DBL_MAX)
virtual void	SampleSecondaries (std::vector< G4DynamicParticle * > *, const G4MaterialCutsCouple *, const G4DynamicParticle *, G4double tmin, G4double maxEnergy)
Public Member Functions inherited from G4VEmModel
	G4VEmModel (const G4String &nam)
virtual	~G4VEmModel ()
virtual void	InitialiseForMaterial (const G4ParticleDefinition *, const G4Material *)
virtual G4double	ComputeDEDXPerVolume (const G4Material *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=DBL_MAX)
virtual G4double	CrossSectionPerVolume (const G4Material *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
virtual G4double	ChargeSquareRatio (const G4Track &)
virtual G4double	GetChargeSquareRatio (const G4ParticleDefinition *, const G4Material *, G4double kineticEnergy)
virtual G4double	GetParticleCharge (const G4ParticleDefinition *, const G4Material *, G4double kineticEnergy)
virtual void	StartTracking (G4Track *)
virtual void	CorrectionsAlongStep (const G4MaterialCutsCouple *, const G4DynamicParticle *, G4double &eloss, G4double &niel, G4double length)
virtual G4double	Value (const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy)
virtual G4double	MinPrimaryEnergy (const G4Material *, const G4ParticleDefinition *, G4double cut=0.0)
virtual G4double	MinEnergyCut (const G4ParticleDefinition *, const G4MaterialCutsCouple *)
virtual void	SetupForMaterial (const G4ParticleDefinition *, const G4Material *, G4double kineticEnergy)
virtual void	DefineForRegion (const G4Region *)
void	InitialiseElementSelectors (const G4ParticleDefinition *, const G4DataVector &)
std::vector < G4EmElementSelector * > *	GetElementSelectors ()
void	SetElementSelectors (std::vector< G4EmElementSelector * > *)
G4double	ComputeDEDX (const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=DBL_MAX)
G4double	CrossSection (const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
G4double	ComputeMeanFreePath (const G4ParticleDefinition *, G4double kineticEnergy, const G4Material *, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
G4double	ComputeCrossSectionPerAtom (const G4ParticleDefinition *, const G4Element *, G4double kinEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
G4int	SelectIsotopeNumber (const G4Element *)
const G4Element *	SelectRandomAtom (const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
const G4Element *	SelectRandomAtom (const G4Material *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
G4int	SelectRandomAtomNumber (const G4Material *)
void	SetParticleChange (G4VParticleChange *, G4VEmFluctuationModel *f=0)
void	SetCrossSectionTable (G4PhysicsTable *, G4bool isLocal)
G4ElementData *	GetElementData ()
G4PhysicsTable *	GetCrossSectionTable ()
G4VEmFluctuationModel *	GetModelOfFluctuations ()
G4VEmAngularDistribution *	GetAngularDistribution ()
void	SetAngularDistribution (G4VEmAngularDistribution *)
G4double	HighEnergyLimit () const
G4double	LowEnergyLimit () const
G4double	HighEnergyActivationLimit () const
G4double	LowEnergyActivationLimit () const
G4double	PolarAngleLimit () const
G4double	SecondaryThreshold () const
G4bool	LPMFlag () const
G4bool	DeexcitationFlag () const
G4bool	ForceBuildTableFlag () const
G4bool	UseAngularGeneratorFlag () const
void	SetAngularGeneratorFlag (G4bool)
void	SetHighEnergyLimit (G4double)
void	SetLowEnergyLimit (G4double)
void	SetActivationHighEnergyLimit (G4double)
void	SetActivationLowEnergyLimit (G4double)
G4bool	IsActive (G4double kinEnergy)
void	SetPolarAngleLimit (G4double)
void	SetSecondaryThreshold (G4double)
void	SetLPMFlag (G4bool val)
void	SetDeexcitationFlag (G4bool val)
void	SetForceBuildTable (G4bool val)
void	SetMasterThread (G4bool val)
G4bool	IsMaster () const
G4double	MaxSecondaryKinEnergy (const G4DynamicParticle *dynParticle)
const G4String &	GetName () const
void	SetCurrentCouple (const G4MaterialCutsCouple *)
const G4Element *	GetCurrentElement () const

Additional Inherited Members
Protected Member Functions inherited from G4VEmModel
G4ParticleChangeForLoss *	GetParticleChangeForLoss ()
G4ParticleChangeForGamma *	GetParticleChangeForGamma ()
virtual G4double	MaxSecondaryEnergy (const G4ParticleDefinition *, G4double kineticEnergy)
const G4MaterialCutsCouple *	CurrentCouple () const
void	SetCurrentElement (const G4Element *)
Protected Attributes inherited from G4VEmModel
G4ElementData *	fElementData
G4VParticleChange *	pParticleChange
G4PhysicsTable *	xSectionTable
const std::vector< G4double > *	theDensityFactor
const std::vector< G4int > *	theDensityIdx
size_t	idxTable

Detailed Description

Definition at line 48 of file G4LivermoreComptonModel.hh.

Constructor & Destructor Documentation

G4LivermoreComptonModel::G4LivermoreComptonModel	(	const G4ParticleDefinition *	p = 0,
		const G4String &	nam = "LivermoreCompton"
	)

Definition at line 69 of file G4LivermoreComptonModel.cc.

References python.hepunit::eV, G4cout, G4endl, and G4VEmModel::SetDeexcitationFlag().

  : G4VEmModel(nam),isInitialised(false)
{
  lowestEnergy = 10 * eV;

  verboseLevel=1 ;
  // Verbosity scale:
  // 0 = nothing 
  // 1 = warning for energy non-conservation 
  // 2 = details of energy budget
  // 3 = calculation of cross sections, file openings, sampling of atoms
  // 4 = entering in methods

  if(  verboseLevel>1 ) { 
    G4cout << "Livermore Compton model is constructed " << G4endl;
  }

  //Mark this model as "applicable" for atomic deexcitation
  SetDeexcitationFlag(true);

  fParticleChange = 0;
  fAtomDeexcitation = 0;
}

G4LivermoreComptonModel::~G4LivermoreComptonModel ( )

virtual

Definition at line 96 of file G4LivermoreComptonModel.cc.

References G4VEmModel::IsMaster().

{  
  if(IsMaster()) {
    delete shellData;
    shellData = 0;
    delete profileData;
    profileData = 0;
  }
}

Member Function Documentation

G4double G4LivermoreComptonModel::ComputeCrossSectionPerAtom ( const G4ParticleDefinition *  , G4double  kinEnergy, G4double  Z, G4double  A = 0, G4double  cut = 0, G4double  emax = DBL_MAX  )

virtual

Reimplemented from G4VEmModel.

Definition at line 236 of file G4LivermoreComptonModel.cc.

References G4PhysicsVector::Energy(), G4cout, G4endl, G4lrint(), G4PhysicsVector::GetVectorLength(), InitialiseForElement(), n, and G4PhysicsVector::Value().

{
  if (verboseLevel > 3) {
    G4cout << "G4LivermoreComptonModel::ComputeCrossSectionPerAtom()" 
       << G4endl;
  }
  G4double cs = 0.0; 

  if (GammaEnergy < lowestEnergy) { return 0.0; }

  G4int intZ = G4lrint(Z);
  if(intZ < 1 || intZ > maxZ) { return cs; } 

  G4LPhysicsFreeVector* pv = data[intZ];

  // if element was not initialised
  // do initialisation safely for MT mode
  if(!pv) 
    {
      InitialiseForElement(0, intZ);
      pv = data[intZ];
      if(!pv) { return cs; }
    }

  G4int n = pv->GetVectorLength() - 1;   
  G4double e1 = pv->Energy(0);
  G4double e2 = pv->Energy(n);

  if(GammaEnergy <= e1)      { cs = GammaEnergy/(e1*e1)*pv->Value(e1); }
  else if(GammaEnergy <= e2) { cs = pv->Value(GammaEnergy)/GammaEnergy; }
  else if(GammaEnergy > e2)  { cs = pv->Value(e2)/GammaEnergy; }
 
  return cs;
}

void G4LivermoreComptonModel::Initialise ( const G4ParticleDefinition *  particle, const G4DataVector &  cuts  )

virtual

Implements G4VEmModel.

Definition at line 108 of file G4LivermoreComptonModel.cc.

References G4LossTableManager::AtomDeexcitation(), python.hepunit::eV, G4cout, G4endl, G4lrint(), G4Material::GetElementVector(), G4MaterialCutsCouple::GetMaterial(), G4ProductionCutsTable::GetMaterialCutsCouple(), G4Material::GetNumberOfElements(), G4VEmModel::GetParticleChangeForGamma(), G4ProductionCutsTable::GetProductionCutsTable(), G4ProductionCutsTable::GetTableSize(), python.hepunit::GeV, G4VEmModel::HighEnergyLimit(), G4VEmModel::InitialiseElementSelectors(), G4LossTableManager::Instance(), G4VEmModel::IsMaster(), G4ShellData::LoadData(), G4VEmModel::LowEnergyLimit(), eplot::material, and G4ShellData::SetOccupancyData().

{
  if (verboseLevel > 1) {
    G4cout << "Calling G4LivermoreComptonModel::Initialise()" << G4endl;
  }

  // Initialise element selector
  
  if(IsMaster()) {

    // Access to elements

    char* path = getenv("G4LEDATA");

    G4ProductionCutsTable* theCoupleTable = 
      G4ProductionCutsTable::GetProductionCutsTable();
    G4int numOfCouples = theCoupleTable->GetTableSize();
  
    for(G4int i=0; i<numOfCouples; ++i) {
      const G4Material* material = 
    theCoupleTable->GetMaterialCutsCouple(i)->GetMaterial();
      const G4ElementVector* theElementVector = material->GetElementVector();
      G4int nelm = material->GetNumberOfElements();
    
      for (G4int j=0; j<nelm; ++j) {
    G4int Z = G4lrint((*theElementVector)[j]->GetZ());
    if(Z < 1)        { Z = 1; }
    else if(Z > maxZ){ Z = maxZ; }

    if( (!data[Z]) ) { ReadData(Z, path); }
      }
    }

    // For Doppler broadening
    if(!shellData) {
      shellData = new G4ShellData(); 
      shellData->SetOccupancyData();
      G4String file = "/doppler/shell-doppler";
      shellData->LoadData(file);
    }
    if(!profileData) { profileData = new G4DopplerProfile(); }

    InitialiseElementSelectors(particle, cuts);
  }

  if (verboseLevel > 2) {
    G4cout << "Loaded cross section files" << G4endl;
  }
 
  if( verboseLevel>1 ) { 
    G4cout << "G4LivermoreComptonModel is initialized " << G4endl
       << "Energy range: "
       << LowEnergyLimit() / eV << " eV - "
       << HighEnergyLimit() / GeV << " GeV"
       << G4endl;
  }
  //  
  if(isInitialised) { return; }

  fParticleChange = GetParticleChangeForGamma();
  fAtomDeexcitation  = G4LossTableManager::Instance()->AtomDeexcitation();
  isInitialised = true;
}

void G4LivermoreComptonModel::InitialiseForElement ( const G4ParticleDefinition *  , G4int  Z  )

virtual

Reimplemented from G4VEmModel.

Definition at line 549 of file G4LivermoreComptonModel.cc.

References G4TemplateAutoLock< M, L, U >::unlock().

Referenced by ComputeCrossSectionPerAtom().

{
  G4AutoLock l(&LivermoreComptonModelMutex);
  //  G4cout << "G4LivermoreComptonModel::InitialiseForElement Z= " 
  //   << Z << G4endl;
  if(!data[Z]) { ReadData(Z); }
  l.unlock();
}

void G4LivermoreComptonModel::InitialiseLocal ( const G4ParticleDefinition *  , G4VEmModel *  masterModel  )

virtual

Reimplemented from G4VEmModel.

Definition at line 175 of file G4LivermoreComptonModel.cc.

References G4VEmModel::GetElementSelectors(), and G4VEmModel::SetElementSelectors().

{
  SetElementSelectors(masterModel->GetElementSelectors());
}

void G4LivermoreComptonModel::SampleSecondaries ( std::vector< G4DynamicParticle * > *  fvect, const G4MaterialCutsCouple *  couple, const G4DynamicParticle *  aDynamicGamma, G4double  tmin, G4double  maxEnergy  )

virtual

Implements G4VEmModel.

Definition at line 277 of file G4LivermoreComptonModel.cc.

References G4ShellData::BindingEnergy(), python.hepunit::c_light, G4VAtomDeexcitation::CheckDeexcitationActiveRegion(), python.hepunit::cm, G4Electron::Electron(), python.hepunit::electron_mass_c2, python.hepunit::fine_structure_const, fStopAndKill, G4cout, G4endl, G4Exp(), G4Log(), G4lrint(), G4UniformRand, G4VAtomDeexcitation::GenerateParticles(), G4VAtomDeexcitation::GetAtomicShell(), G4DynamicParticle::GetDefinition(), G4MaterialCutsCouple::GetIndex(), G4DynamicParticle::GetKineticEnergy(), G4MaterialCutsCouple::GetMaterial(), G4DynamicParticle::GetMomentumDirection(), G4Material::GetName(), G4Element::GetZ(), python.hepunit::h_Planck, python.hepunit::keV, python.hepunit::MeV, G4VParticleChange::ProposeLocalEnergyDeposit(), G4ParticleChangeForGamma::ProposeMomentumDirection(), G4VParticleChange::ProposeTrackStatus(), G4DopplerProfile::RandomSelectMomentum(), CLHEP::Hep3Vector::rotateUz(), G4VEmModel::SelectRandomAtom(), G4ShellData::SelectRandomShell(), G4ParticleChangeForGamma::SetProposedKineticEnergy(), python.hepunit::twopi, var(), and test::x.

{

  // The scattered gamma energy is sampled according to Klein - Nishina 
  // formula then accepted or rejected depending on the Scattering Function 
  // multiplied by factor from Klein - Nishina formula.
  // Expression of the angular distribution as Klein Nishina
  // angular and energy distribution and Scattering fuctions is taken from
  // D. E. Cullen "A simple model of photon transport" Nucl. Instr. Meth.
  // Phys. Res. B 101 (1995). Method of sampling with form factors is different
  // data are interpolated while in the article they are fitted.
  // Reference to the article is from J. Stepanek New Photon, Positron
  // and Electron Interaction Data for GEANT in Energy Range from 1 eV to 10
  // TeV (draft).
  // The random number techniques of Butcher & Messel are used
  // (Nucl Phys 20(1960),15).

  G4double photonEnergy0 = aDynamicGamma->GetKineticEnergy();

  if (verboseLevel > 3) {
    G4cout << "G4LivermoreComptonModel::SampleSecondaries() E(MeV)= " 
       << photonEnergy0/MeV << " in " << couple->GetMaterial()->GetName() 
       << G4endl;
  }
  
  // low-energy gamma is absorpted by this process
  if (photonEnergy0 <= lowestEnergy) 
    {
      fParticleChange->ProposeTrackStatus(fStopAndKill);
      fParticleChange->SetProposedKineticEnergy(0.);
      fParticleChange->ProposeLocalEnergyDeposit(photonEnergy0);
      return ;
    }

  G4double e0m = photonEnergy0 / electron_mass_c2 ;
  G4ParticleMomentum photonDirection0 = aDynamicGamma->GetMomentumDirection();

  // Select randomly one element in the current material
  const G4ParticleDefinition* particle =  aDynamicGamma->GetDefinition();
  const G4Element* elm = SelectRandomAtom(couple,particle,photonEnergy0);

  G4int Z = G4lrint(elm->GetZ());

  G4double epsilon0Local = 1. / (1. + 2. * e0m);
  G4double epsilon0Sq = epsilon0Local * epsilon0Local;
  G4double alpha1 = -G4Log(epsilon0Local);
  G4double alpha2 = 0.5 * (1. - epsilon0Sq);

  G4double wlPhoton = h_Planck*c_light/photonEnergy0;

  // Sample the energy of the scattered photon
  G4double epsilon;
  G4double epsilonSq;
  G4double oneCosT;
  G4double sinT2;
  G4double gReject;

  if (verboseLevel > 3) {
    G4cout << "Started loop to sample gamma energy" << G4endl;
  }
  
  do {
    if ( alpha1/(alpha1+alpha2) > G4UniformRand())
      {
        epsilon = G4Exp(-alpha1 * G4UniformRand());  
        epsilonSq = epsilon * epsilon;
      }
      else
      {
        epsilonSq = epsilon0Sq + (1. - epsilon0Sq) * G4UniformRand();
        epsilon = std::sqrt(epsilonSq);
      }

      oneCosT = (1. - epsilon) / ( epsilon * e0m);
      sinT2 = oneCosT * (2. - oneCosT);
      G4double x = std::sqrt(oneCosT/2.) * cm / wlPhoton;
      G4double scatteringFunction = ComputeScatteringFunction(x, Z);
      gReject = (1. - epsilon * sinT2 / (1. + epsilonSq)) * scatteringFunction;

  } while(gReject < G4UniformRand()*Z);

  G4double cosTheta = 1. - oneCosT;
  G4double sinTheta = std::sqrt (sinT2);
  G4double phi = twopi * G4UniformRand() ;
  G4double dirx = sinTheta * std::cos(phi);
  G4double diry = sinTheta * std::sin(phi);
  G4double dirz = cosTheta ;

  // Doppler broadening -  Method based on:
  // Y. Namito, S. Ban and H. Hirayama, 
  // "Implementation of the Doppler Broadening of a Compton-Scattered Photon 
  // into the EGS4 Code", NIM A 349, pp. 489-494, 1994
  
  // Maximum number of sampling iterations
  static G4int maxDopplerIterations = 1000;
  G4double bindingE = 0.;
  G4double photonEoriginal = epsilon * photonEnergy0;
  G4double photonE = -1.;
  G4int iteration = 0;
  G4double eMax = photonEnergy0;

  G4int shellIdx = 0;

  if (verboseLevel > 3) {
    G4cout << "Started loop to sample broading" << G4endl;
  }

  do
    {
      ++iteration;
      // Select shell based on shell occupancy
      shellIdx = shellData->SelectRandomShell(Z);
      bindingE = shellData->BindingEnergy(Z,shellIdx);

      if (verboseLevel > 3) {
    G4cout << "Shell ID= " << shellIdx 
           << " Ebind(keV)= " << bindingE/keV << G4endl;
      }
      
      eMax = photonEnergy0 - bindingE;
     
      // Randomly sample bound electron momentum 
      // (memento: the data set is in Atomic Units)
      G4double pSample = profileData->RandomSelectMomentum(Z,shellIdx);
      if (verboseLevel > 3) {
    G4cout << "pSample= " << pSample << G4endl;
      }
      // Rescale from atomic units
      G4double pDoppler = pSample * fine_structure_const;
      G4double pDoppler2 = pDoppler * pDoppler;
      G4double var2 = 1. + oneCosT * e0m;
      G4double var3 = var2*var2 - pDoppler2;
      G4double var4 = var2 - pDoppler2 * cosTheta;
      G4double var = var4*var4 - var3 + pDoppler2 * var3;
      if (var > 0.)
    {
      G4double varSqrt = std::sqrt(var);        
      G4double scale = photonEnergy0 / var3;  
          // Random select either root
      if (G4UniformRand() < 0.5) { photonE = (var4 - varSqrt) * scale; }
      else                       { photonE = (var4 + varSqrt) * scale; }
    } 
      else
    {
      photonE = -1.;
    }
   } while (iteration <= maxDopplerIterations && photonE > eMax); 
  // (photonE < 0. || photonE > eMax || photonE < eMax*G4UniformRand()) );
        
 
  // End of recalculation of photon energy with Doppler broadening
  // Revert to original if maximum number of iterations threshold 
  // has been reached

  if (iteration >= maxDopplerIterations)
    {
      photonE = photonEoriginal;
      bindingE = 0.;
    }

  // Update G4VParticleChange for the scattered photon

  G4ThreeVector photonDirection1(dirx,diry,dirz);
  photonDirection1.rotateUz(photonDirection0);
  fParticleChange->ProposeMomentumDirection(photonDirection1) ;

  G4double photonEnergy1 = photonE;

  if (photonEnergy1 > 0.) {
    fParticleChange->SetProposedKineticEnergy(photonEnergy1) ;

  } else {
    // photon absorbed
    photonEnergy1 = 0.;
    fParticleChange->SetProposedKineticEnergy(0.) ;
    fParticleChange->ProposeTrackStatus(fStopAndKill);   
    fParticleChange->ProposeLocalEnergyDeposit(photonEnergy0);
    return;
  }

  // Kinematics of the scattered electron
  G4double eKineticEnergy = photonEnergy0 - photonEnergy1 - bindingE;

  // protection against negative final energy: no e- is created
  if(eKineticEnergy < 0.0) {
    fParticleChange->ProposeLocalEnergyDeposit(photonEnergy0 - photonEnergy1);
    return;
  }

  G4double eTotalEnergy = eKineticEnergy + electron_mass_c2;

  G4double electronE = photonEnergy0 * (1. - epsilon) + electron_mass_c2; 
  G4double electronP2 = 
    electronE*electronE - electron_mass_c2*electron_mass_c2;
  G4double sinThetaE = -1.;
  G4double cosThetaE = 0.;
  if (electronP2 > 0.)
    {
      cosThetaE = (eTotalEnergy + photonEnergy1 )* 
    (1. - epsilon) / std::sqrt(electronP2);
      sinThetaE = -1. * sqrt(1. - cosThetaE * cosThetaE); 
    }
  
  G4double eDirX = sinThetaE * std::cos(phi);
  G4double eDirY = sinThetaE * std::sin(phi);
  G4double eDirZ = cosThetaE;

  G4ThreeVector eDirection(eDirX,eDirY,eDirZ);
  eDirection.rotateUz(photonDirection0);
  G4DynamicParticle* dp = new G4DynamicParticle (G4Electron::Electron(),
                         eDirection,eKineticEnergy) ;
  fvect->push_back(dp);

  // sample deexcitation
  //

  if (verboseLevel > 3) {
    G4cout << "Started atomic de-excitation " << fAtomDeexcitation << G4endl;
  }

  if(fAtomDeexcitation && iteration < maxDopplerIterations) {
    G4int index = couple->GetIndex();
    if(fAtomDeexcitation->CheckDeexcitationActiveRegion(index)) {
      size_t nbefore = fvect->size();
      G4AtomicShellEnumerator as = G4AtomicShellEnumerator(shellIdx);
      const G4AtomicShell* shell = fAtomDeexcitation->GetAtomicShell(Z, as);
      fAtomDeexcitation->GenerateParticles(fvect, shell, Z, index);
      size_t nafter = fvect->size();
      if(nafter > nbefore) {
    for (size_t i=nbefore; i<nafter; ++i) {
      bindingE -= ((*fvect)[i])->GetKineticEnergy();
    } 
      }
    }
  }
  if(bindingE < 0.0) { bindingE = 0.0; }
  fParticleChange->ProposeLocalEnergyDeposit(bindingE);
}

---

The documentation for this class was generated from the following files:

• G4LivermoreComptonModel.hh
• G4LivermoreComptonModel.cc