G4LivermorePolarizedComptonModel Class Reference

#include <G4LivermorePolarizedComptonModel.hh>

Inheritance diagram for G4LivermorePolarizedComptonModel:

Public Member Functions
	G4LivermorePolarizedComptonModel (const G4ParticleDefinition *p=0, const G4String &nam="LivermorePolarizedCompton")
virtual	~G4LivermorePolarizedComptonModel ()
virtual void	Initialise (const G4ParticleDefinition *, const G4DataVector &)
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	InitialiseLocal (const G4ParticleDefinition *, G4VEmModel *masterModel)
virtual void	InitialiseForMaterial (const G4ParticleDefinition *, const G4Material *)
virtual void	InitialiseForElement (const G4ParticleDefinition *, G4int Z)
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

Protected Attributes
G4ParticleChangeForGamma *	fParticleChange
Protected Attributes inherited from G4VEmModel
G4ElementData *	fElementData
G4VParticleChange *	pParticleChange
G4PhysicsTable *	xSectionTable
const std::vector< G4double > *	theDensityFactor
const std::vector< G4int > *	theDensityIdx
size_t	idxTable

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 *)

Detailed Description

Definition at line 45 of file G4LivermorePolarizedComptonModel.hh.

Constructor & Destructor Documentation

G4LivermorePolarizedComptonModel::G4LivermorePolarizedComptonModel	(	const G4ParticleDefinition *	p = 0,
		const G4String &	nam = "LivermorePolarizedCompton"
	)

Definition at line 51 of file G4LivermorePolarizedComptonModel.cc.

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

  :G4VEmModel(nam),fParticleChange(0),isInitialised(false),
   meanFreePathTable(0),scatterFunctionData(0),crossSectionHandler(0)
{
  lowEnergyLimit = 250 * eV; 
  highEnergyLimit = 100 * GeV;
  //SetLowEnergyLimit(lowEnergyLimit);
  SetHighEnergyLimit(highEnergyLimit);
  
  verboseLevel= 0;
  // 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>0 ) { 
  G4cout << "Livermore Polarized Compton is constructed " << G4endl
         << "Energy range: "
         << lowEnergyLimit / eV << " eV - "
         << highEnergyLimit / GeV << " GeV"
         << G4endl;
  }
}

G4LivermorePolarizedComptonModel::~G4LivermorePolarizedComptonModel ( )

virtual

Definition at line 80 of file G4LivermorePolarizedComptonModel.cc.

{  
  if (meanFreePathTable)   delete meanFreePathTable;
  if (crossSectionHandler) delete crossSectionHandler;
  if (scatterFunctionData) delete scatterFunctionData;
}

Member Function Documentation

G4double G4LivermorePolarizedComptonModel::ComputeCrossSectionPerAtom ( const G4ParticleDefinition *  , G4double  kinEnergy, G4double  Z, G4double  A = 0, G4double  cut = 0, G4double  emax = DBL_MAX  )

virtual

Reimplemented from G4VEmModel.

Definition at line 143 of file G4LivermorePolarizedComptonModel.cc.

References G4VCrossSectionHandler::FindValue(), G4cout, and G4endl.

{
  if (verboseLevel > 3)
    G4cout << "Calling ComputeCrossSectionPerAtom() of G4LivermorePolarizedComptonModel" << G4endl;

  if (GammaEnergy < lowEnergyLimit || GammaEnergy > highEnergyLimit) return 0.0;

  G4double cs = crossSectionHandler->FindValue(G4int(Z), GammaEnergy);
  return cs;
}

void G4LivermorePolarizedComptonModel::Initialise ( const G4ParticleDefinition *  particle, const G4DataVector &  cuts  )

virtual

Implements G4VEmModel.

Definition at line 89 of file G4LivermorePolarizedComptonModel.cc.

References G4VCrossSectionHandler::BuildMeanFreePathForMaterials(), G4VCrossSectionHandler::Clear(), python.hepunit::eV, fParticleChange, G4cout, G4endl, G4VEmModel::GetParticleChangeForGamma(), python.hepunit::GeV, G4VEmModel::HighEnergyLimit(), G4VEmModel::InitialiseElementSelectors(), G4ShellData::LoadData(), G4VEMDataSet::LoadData(), G4VCrossSectionHandler::LoadData(), G4VEmModel::LowEnergyLimit(), and G4ShellData::SetOccupancyData().

{
  if (verboseLevel > 3)
    G4cout << "Calling G4LivermorePolarizedComptonModel::Initialise()" << G4endl;

  if (crossSectionHandler)
  {
    crossSectionHandler->Clear();
    delete crossSectionHandler;
  }

  // Reading of data files - all materials are read
  
  crossSectionHandler = new G4CrossSectionHandler;
  crossSectionHandler->Clear();
  G4String crossSectionFile = "comp/ce-cs-";
  crossSectionHandler->LoadData(crossSectionFile);

  meanFreePathTable = 0;
  meanFreePathTable = crossSectionHandler->BuildMeanFreePathForMaterials();

  G4VDataSetAlgorithm* scatterInterpolation = new G4LogLogInterpolation;
  G4String scatterFile = "comp/ce-sf-";
  scatterFunctionData = new G4CompositeEMDataSet(scatterInterpolation, 1., 1.);
  scatterFunctionData->LoadData(scatterFile);

  // For Doppler broadening
  shellData.SetOccupancyData();
  G4String file = "/doppler/shell-doppler";
  shellData.LoadData(file);

  if (verboseLevel > 2) 
    G4cout << "Loaded cross section files for Livermore Polarized Compton model" << G4endl;

  InitialiseElementSelectors(particle,cuts);

  if(  verboseLevel>0 ) { 
    G4cout << "Livermore Polarized Compton model is initialized " << G4endl
         << "Energy range: "
         << LowEnergyLimit() / eV << " eV - "
         << HighEnergyLimit() / GeV << " GeV"
         << G4endl;
  }
  
  //
    
  if(isInitialised) return;
  fParticleChange = GetParticleChangeForGamma();
  isInitialised = true;
}

void G4LivermorePolarizedComptonModel::SampleSecondaries ( std::vector< G4DynamicParticle * > *  fvect, const G4MaterialCutsCouple *  couple, const G4DynamicParticle *  aDynamicGamma, G4double  tmin, G4double  maxEnergy  )

virtual

Implements G4VEmModel.

Definition at line 160 of file G4LivermorePolarizedComptonModel.cc.

References G4ShellData::BindingEnergy(), python.hepunit::c_light, python.hepunit::cm, G4Electron::Electron(), python.hepunit::electron_mass_c2, G4VEMDataSet::FindValue(), python.hepunit::fine_structure_const, fParticleChange, fStopAndKill, G4cout, G4endl, G4UniformRand, G4DynamicParticle::GetDefinition(), G4DynamicParticle::GetKineticEnergy(), G4DynamicParticle::GetMomentumDirection(), G4DynamicParticle::GetPolarization(), G4Element::GetZ(), python.hepunit::h_Planck, CLHEP::Hep3Vector::howOrthogonal(), CLHEP::Hep3Vector::isOrthogonal(), CLHEP::Hep3Vector::mag(), G4VParticleChange::ProposeLocalEnergyDeposit(), G4ParticleChangeForGamma::ProposeMomentumDirection(), G4ParticleChangeForGamma::ProposePolarization(), G4VParticleChange::ProposeTrackStatus(), G4DopplerProfile::RandomSelectMomentum(), G4VEmModel::SelectRandomAtom(), G4ShellData::SelectRandomShell(), G4ParticleChangeForGamma::SetProposedKineticEnergy(), CLHEP::Hep3Vector::unit(), var(), and test::x.

{
  // The scattered gamma energy is sampled according to Klein - Nishina formula.
  // The random number techniques of Butcher & Messel are used (Nuc Phys 20(1960),15).
  // GEANT4 internal units
  //
  // Note : Effects due to binding of atomic electrons are negliged.

  if (verboseLevel > 3)
    G4cout << "Calling SampleSecondaries() of G4LivermorePolarizedComptonModel" << G4endl;

  G4double gammaEnergy0 = aDynamicGamma->GetKineticEnergy();
  G4ThreeVector gammaPolarization0 = aDynamicGamma->GetPolarization();

  // Protection: a polarisation parallel to the
  // direction causes problems;
  // in that case find a random polarization

  G4ThreeVector gammaDirection0 = aDynamicGamma->GetMomentumDirection();

  // Make sure that the polarization vector is perpendicular to the
  // gamma direction. If not

  if(!(gammaPolarization0.isOrthogonal(gammaDirection0, 1e-6))||(gammaPolarization0.mag()==0))
    { // only for testing now
      gammaPolarization0 = GetRandomPolarization(gammaDirection0);
    }
  else
    {
      if ( gammaPolarization0.howOrthogonal(gammaDirection0) != 0)
    {
      gammaPolarization0 = GetPerpendicularPolarization(gammaDirection0, gammaPolarization0);
    }
    }

  // End of Protection

  // Within energy limit?

  if(gammaEnergy0 <= lowEnergyLimit)
    {
      fParticleChange->ProposeTrackStatus(fStopAndKill);
      fParticleChange->SetProposedKineticEnergy(0.);
      fParticleChange->ProposeLocalEnergyDeposit(gammaEnergy0);
      return;
    }

  G4double E0_m = gammaEnergy0 / electron_mass_c2 ;

  // Select randomly one element in the current material
  //G4int Z = crossSectionHandler->SelectRandomAtom(couple,gammaEnergy0);
  const G4ParticleDefinition* particle =  aDynamicGamma->GetDefinition();
  const G4Element* elm = SelectRandomAtom(couple,particle,gammaEnergy0);
  G4int Z = (G4int)elm->GetZ();

  // Sample the energy and the polarization of the scattered photon

  G4double epsilon, epsilonSq, onecost, sinThetaSqr, greject ;

  G4double epsilon0Local = 1./(1. + 2*E0_m);
  G4double epsilon0Sq = epsilon0Local*epsilon0Local;
  G4double alpha1   = - std::log(epsilon0Local);
  G4double alpha2 = 0.5*(1.- epsilon0Sq);

  G4double wlGamma = h_Planck*c_light/gammaEnergy0;
  G4double gammaEnergy1;
  G4ThreeVector gammaDirection1;

  do {
    if ( alpha1/(alpha1+alpha2) > G4UniformRand() )
      {
    epsilon   = std::exp(-alpha1*G4UniformRand());  
    epsilonSq = epsilon*epsilon; 
      }
    else 
      {
    epsilonSq = epsilon0Sq + (1.- epsilon0Sq)*G4UniformRand();
    epsilon   = std::sqrt(epsilonSq);
      }

    onecost = (1.- epsilon)/(epsilon*E0_m);
    sinThetaSqr   = onecost*(2.-onecost);

    // Protection
    if (sinThetaSqr > 1.)
      {
    G4cout
      << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
      << "sin(theta)**2 = "
      << sinThetaSqr
      << "; set to 1"
      << G4endl;
    sinThetaSqr = 1.;
      }
    if (sinThetaSqr < 0.)
      {
    G4cout
      << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
      << "sin(theta)**2 = "
      << sinThetaSqr
      << "; set to 0"
      << G4endl;
    sinThetaSqr = 0.;
      }
    // End protection

    G4double x =  std::sqrt(onecost/2.) / (wlGamma/cm);;
    G4double scatteringFunction = scatterFunctionData->FindValue(x,Z-1);
    greject = (1. - epsilon*sinThetaSqr/(1.+ epsilonSq))*scatteringFunction;

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


  // ****************************************************
  //        Phi determination
  // ****************************************************

  G4double phi = SetPhi(epsilon,sinThetaSqr);

  //
  // scattered gamma angles. ( Z - axis along the parent gamma)
  //

  G4double cosTheta = 1. - onecost;

  // Protection

  if (cosTheta > 1.)
    {
      G4cout
    << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
    << "cosTheta = "
    << cosTheta
    << "; set to 1"
    << G4endl;
      cosTheta = 1.;
    }
  if (cosTheta < -1.)
    {
      G4cout 
    << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
    << "cosTheta = " 
    << cosTheta
    << "; set to -1"
    << G4endl;
      cosTheta = -1.;
    }
  // End protection      
  
  
  G4double sinTheta = std::sqrt (sinThetaSqr);
  
  // Protection
  if (sinTheta > 1.)
    {
      G4cout 
    << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
    << "sinTheta = " 
    << sinTheta
    << "; set to 1"
    << G4endl;
      sinTheta = 1.;
    }
  if (sinTheta < -1.)
    {
      G4cout 
    << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
    << "sinTheta = " 
    << sinTheta
    << "; set to -1" 
    << G4endl;
      sinTheta = -1.;
    }
  // End protection
  
      
  G4double dirx = sinTheta*std::cos(phi);
  G4double diry = sinTheta*std::sin(phi);
  G4double dirz = cosTheta ;
  

  // oneCosT , eom

  // 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

  G4int maxDopplerIterations = 1000;
  G4double bindingE = 0.;
  G4double photonEoriginal = epsilon * gammaEnergy0;
  G4double photonE = -1.;
  G4int iteration = 0;
  G4double eMax = gammaEnergy0;

  do
    {
      iteration++;
      // Select shell based on shell occupancy
      G4int shell = shellData.SelectRandomShell(Z);
      bindingE = shellData.BindingEnergy(Z,shell);
      
      eMax = gammaEnergy0 - bindingE;
     
      // Randomly sample bound electron momentum (memento: the data set is in Atomic Units)
      G4double pSample = profileData.RandomSelectMomentum(Z,shell);
      // Rescale from atomic units
      G4double pDoppler = pSample * fine_structure_const;
      G4double pDoppler2 = pDoppler * pDoppler;
      G4double var2 = 1. + onecost * E0_m;
      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 = gammaEnergy0 / 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 < 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.;
    }

  gammaEnergy1 = photonE;
 
  //
  // update G4VParticleChange for the scattered photon 
  //

  //  gammaEnergy1 = epsilon*gammaEnergy0;


  // New polarization

  G4ThreeVector gammaPolarization1 = SetNewPolarization(epsilon,
                            sinThetaSqr,
                            phi,
                            cosTheta);

  // Set new direction
  G4ThreeVector tmpDirection1( dirx,diry,dirz );
  gammaDirection1 = tmpDirection1;

  // Change reference frame.

  SystemOfRefChange(gammaDirection0,gammaDirection1,
            gammaPolarization0,gammaPolarization1);

  if (gammaEnergy1 > 0.)
    {
      fParticleChange->SetProposedKineticEnergy( gammaEnergy1 ) ;
      fParticleChange->ProposeMomentumDirection( gammaDirection1 );
      fParticleChange->ProposePolarization( gammaPolarization1 );
    }
  else
    {
      gammaEnergy1 = 0.;
      fParticleChange->SetProposedKineticEnergy(0.) ;
      fParticleChange->ProposeTrackStatus(fStopAndKill);
    }

  //
  // kinematic of the scattered electron
  //

  G4double ElecKineEnergy = gammaEnergy0 - gammaEnergy1 -bindingE;

  // SI -protection against negative final energy: no e- is created
  // like in G4LivermoreComptonModel.cc
  if(ElecKineEnergy < 0.0) {
    fParticleChange->ProposeLocalEnergyDeposit(gammaEnergy0 - gammaEnergy1);
    return;
  }
 
  // SI - Removed range test
  
  G4double ElecMomentum = std::sqrt(ElecKineEnergy*(ElecKineEnergy+2.*electron_mass_c2));

  G4ThreeVector ElecDirection((gammaEnergy0 * gammaDirection0 -
                   gammaEnergy1 * gammaDirection1) * (1./ElecMomentum));

  fParticleChange->ProposeLocalEnergyDeposit(bindingE);
  
  G4DynamicParticle* dp = new G4DynamicParticle (G4Electron::Electron(),ElecDirection.unit(),ElecKineEnergy) ;
  fvect->push_back(dp);

}

Field Documentation

G4ParticleChangeForGamma* G4LivermorePolarizedComptonModel::fParticleChange

protected

Definition at line 73 of file G4LivermorePolarizedComptonModel.hh.

Referenced by Initialise(), and SampleSecondaries().

---

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

• G4LivermorePolarizedComptonModel.hh
• G4LivermorePolarizedComptonModel.cc