#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 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	Initialise (const G4ParticleDefinition *, const G4DataVector &)=0

virtual void	SampleSecondaries (std::vector< G4DynamicParticle * > , const G4MaterialCutsCouple , const G4DynamicParticle *, G4double tmin=0.0, G4double tmax=DBL_MAX)=0

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	ComputeCrossSectionPerAtom (const G4ParticleDefinition *, G4double kinEnergy, G4double Z, G4double A=0., 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 )

virtual void	SetupForMaterial (const G4ParticleDefinition , const G4Material , G4double kineticEnergy)

virtual void	DefineForRegion (const G4Region *)

void	InitialiseElementSelectors (const G4ParticleDefinition *, const G4DataVector &)

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)

void	SetParticleChange (G4VParticleChange , G4VEmFluctuationModel f=0)

void	SetCrossSectionTable (G4PhysicsTable *)

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

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	ForceBuildTable (G4bool val)

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
G4VParticleChange *	pParticleChange

G4PhysicsTable *	xSectionTable

const std::vector< G4double > *	theDensityFactor

const std::vector< G4int > *	theDensityIdx

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 48 of file G4LivermoreComptonModel.hh.

Constructor & Destructor Documentation

◆ G4LivermoreComptonModel()

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

Definition at line 63 of file G4LivermoreComptonModel.cc.

  :G4VEmModel(nam),fParticleChange(0),isInitialised(false),
   scatterFunctionData(0),
   crossSectionHandler(0),fAtomDeexcitation(0)
{
  lowEnergyLimit = 250 * eV; 
  highEnergyLimit = 100 * GeV;
 
  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 Compton model is constructed " << G4endl
       << "Energy range: "
       << lowEnergyLimit / eV << " eV - "
       << highEnergyLimit / GeV << " GeV"
       << G4endl;
  }
 
  //Mark this model as "applicable" for atomic deexcitation
  SetDeexcitationFlag(true);
 
}

◆ ~G4LivermoreComptonModel()

G4LivermoreComptonModel::~G4LivermoreComptonModel ( )

virtual

Definition at line 95 of file G4LivermoreComptonModel.cc.

{  
  delete crossSectionHandler;
  delete scatterFunctionData;
}

Member Function Documentation

◆ ComputeCrossSectionPerAtom()

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 156 of file G4LivermoreComptonModel.cc.

{
  if (verboseLevel > 3) {
    G4cout << "Calling ComputeCrossSectionPerAtom() of G4LivermoreComptonModel" << G4endl;
  }
  if (GammaEnergy < lowEnergyLimit || GammaEnergy > highEnergyLimit) { return 0.0; }
    
  G4double cs = crossSectionHandler->FindValue(G4int(Z), GammaEnergy);  
  return cs;
}

◆ Initialise()

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

virtual

Implements G4VEmModel.

Definition at line 103 of file G4LivermoreComptonModel.cc.

{
  if (verboseLevel > 2) {
    G4cout << "Calling G4LivermoreComptonModel::Initialise()" << G4endl;
  }
 
  if (crossSectionHandler)
  {
    crossSectionHandler->Clear();
    delete crossSectionHandler;
  }
  delete scatterFunctionData;
 
  // Reading of data files - all materials are read  
  crossSectionHandler = new G4CrossSectionHandler;
  G4String crossSectionFile = "comp/ce-cs-";
  crossSectionHandler->LoadData(crossSectionFile);
 
  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);
 
  InitialiseElementSelectors(particle,cuts);
 
  if (verboseLevel > 2) {
    G4cout << "Loaded cross section files for Livermore Compton model" << G4endl;
  }
 
  if(isInitialised) { return; }
  isInitialised = true;
 
  fParticleChange = GetParticleChangeForGamma();
 
  fAtomDeexcitation  = G4LossTableManager::Instance()->AtomDeexcitation();
 
  if(  verboseLevel>0 ) { 
    G4cout << "Livermore Compton model is initialized " << G4endl
       << "Energy range: "
       << LowEnergyLimit() / eV << " eV - "
       << HighEnergyLimit() / GeV << " GeV"
       << G4endl;
  }  
}

◆ SampleSecondaries()

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

virtual

Implements G4VEmModel.

Definition at line 173 of file G4LivermoreComptonModel.cc.

{
 
  // 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 <= lowEnergyLimit) 
    {
      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 = (G4int)elm->GetZ();
 
  G4double epsilon0Local = 1. / (1. + 2. * e0m);
  G4double epsilon0Sq = epsilon0Local * epsilon0Local;
  G4double alpha1 = -std::log(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;
  
  do
    {
      if ( alpha1/(alpha1+alpha2) > G4UniformRand())
    {
      // std::pow(epsilon0Local,G4UniformRand())
      epsilon = std::exp(-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.) / (wlPhoton/cm);
      G4double scatteringFunction = scatterFunctionData->FindValue(x,Z-1);
      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
  G4int maxDopplerIterations = 1000;
  G4double bindingE = 0.;
  G4double photonEoriginal = epsilon * photonEnergy0;
  G4double photonE = -1.;
  G4int iteration = 0;
  G4double eMax = photonEnergy0;
 
  G4int shellIdx = 0;
 
  do
    {
      ++iteration;
      // Select shell based on shell occupancy
      shellIdx = shellData.SelectRandomShell(Z);
      bindingE = shellData.BindingEnergy(Z,shellIdx);
      
      eMax = photonEnergy0 - bindingE;
     
      // Randomly sample bound electron momentum 
      // (memento: the data set is in Atomic Units)
      G4double pSample = profileData.RandomSelectMomentum(Z,shellIdx);
      // 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 && 
 
// JB : corrected the following condition
//       (photonE < 0. || photonE > eMax || photonE < eMax*G4UniformRand()) );
 
         (photonE > eMax ) );
    
  // 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
    {
      photonEnergy1 = 0.;
      fParticleChange->SetProposedKineticEnergy(0.) ;
      fParticleChange->ProposeTrackStatus(fStopAndKill);   
    }
 
  // Kinematics of the scattered electron
  G4double eKineticEnergy = photonEnergy0 - photonEnergy1 - bindingE;
 
  // protection against negative final energy: no e- is created
  if(eKineticEnergy < 0.0) {
    bindingE = photonEnergy0 - photonEnergy1;
 
  } else {
    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 = -sqrt((1. - cosThetaE) * (1. + 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(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);
}

Member Data Documentation

◆ fParticleChange

G4ParticleChangeForGamma* G4LivermoreComptonModel::fParticleChange

protected

Definition at line 75 of file G4LivermoreComptonModel.hh.

Referenced by Initialise(), and SampleSecondaries().

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

Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ G4LivermoreComptonModel()

◆ ~G4LivermoreComptonModel()

Member Function Documentation

◆ ComputeCrossSectionPerAtom()

◆ Initialise()

◆ SampleSecondaries()

Member Data Documentation

◆ fParticleChange