#include <G4eBremsstrahlungRelModel.hh>

Inheritance diagram for G4eBremsstrahlungRelModel:

Public Member Functions
	G4eBremsstrahlungRelModel (const G4ParticleDefinition *p=nullptr, const G4String &nam="eBremLPM")
	~G4eBremsstrahlungRelModel () override
void	Initialise (const G4ParticleDefinition *, const G4DataVector &) override
void	InitialiseLocal (const G4ParticleDefinition , G4VEmModel masterModel) override
G4double	ComputeDEDXPerVolume (const G4Material , const G4ParticleDefinition , G4double ekin, G4double cutEnergy) override
G4double	ComputeCrossSectionPerAtom (const G4ParticleDefinition *, G4double ekin, G4double zet, G4double, G4double cutEnergy, G4double maxEnergy=DBL_MAX) override
void	SampleSecondaries (std::vector< G4DynamicParticle * > , const G4MaterialCutsCouple , const G4DynamicParticle *, G4double cutEnergy, G4double maxEnergy) override
void	SetupForMaterial (const G4ParticleDefinition , const G4Material , G4double) override
G4double	MinPrimaryEnergy (const G4Material , const G4ParticleDefinition , G4double cutEnergy) override
Public Member Functions inherited from G4VEmModel
	G4VEmModel (const G4String &nam)
virtual	~G4VEmModel ()
virtual void	InitialiseForMaterial (const G4ParticleDefinition , const G4Material )
virtual void	InitialiseForElement (const G4ParticleDefinition *, G4int Z)
virtual G4double	CrossSectionPerVolume (const G4Material , const G4ParticleDefinition , G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
virtual G4double	GetPartialCrossSection (const G4Material , G4int level, const G4ParticleDefinition , G4double kineticEnergy)
virtual G4double	ComputeCrossSectionPerShell (const G4ParticleDefinition *, G4int Z, G4int shellIdx, G4double kinEnergy, 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 G4Material , const G4ParticleDefinition , const G4double kinEnergy, const G4double cutEnergy, const G4double &length, G4double &eloss)
virtual G4double	Value (const G4MaterialCutsCouple , const G4ParticleDefinition , G4double kineticEnergy)
virtual G4double	MinEnergyCut (const G4ParticleDefinition , const G4MaterialCutsCouple )
virtual void	DefineForRegion (const G4Region *)
virtual void	FillNumberOfSecondaries (G4int &numberOfTriplets, G4int &numberOfRecoil)
virtual void	ModelDescription (std::ostream &outFile) const
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)
const G4Element *	SelectRandomAtom (const G4MaterialCutsCouple , const G4ParticleDefinition , G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
const G4Element *	SelectTargetAtom (const G4MaterialCutsCouple , const G4ParticleDefinition , G4double kineticEnergy, G4double logKineticEnergy, 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)
const G4Element *	GetCurrentElement (const G4Material *mat=nullptr) const
G4int	SelectRandomAtomNumber (const G4Material *) const
const G4Isotope *	GetCurrentIsotope (const G4Element *elm=nullptr) const
G4int	SelectIsotopeNumber (const G4Element *) const
void	SetParticleChange (G4VParticleChange , G4VEmFluctuationModel f=nullptr)
void	SetCrossSectionTable (G4PhysicsTable *, G4bool isLocal)
G4ElementData *	GetElementData ()
G4PhysicsTable *	GetCrossSectionTable ()
G4VEmFluctuationModel *	GetModelOfFluctuations ()
G4VEmAngularDistribution *	GetAngularDistribution ()
G4VEmModel *	GetTripletModel ()
void	SetTripletModel (G4VEmModel *)
void	SetAngularDistribution (G4VEmAngularDistribution *)
G4double	HighEnergyLimit () const
G4double	LowEnergyLimit () const
G4double	HighEnergyActivationLimit () const
G4double	LowEnergyActivationLimit () const
G4double	PolarAngleLimit () const
G4double	SecondaryThreshold () 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) const
void	SetPolarAngleLimit (G4double)
void	SetSecondaryThreshold (G4double)
void	SetDeexcitationFlag (G4bool val)
void	SetForceBuildTable (G4bool val)
void	SetFluctuationFlag (G4bool val)
G4bool	IsMaster () const
void	SetUseBaseMaterials (G4bool val)
G4bool	UseBaseMaterials () const
G4double	MaxSecondaryKinEnergy (const G4DynamicParticle *dynParticle)
const G4String &	GetName () const
void	SetCurrentCouple (const G4MaterialCutsCouple *)
G4bool	IsLocked () const
void	SetLocked (G4bool)
void	SetLPMFlag (G4bool)
void	SetMasterThread (G4bool)
G4VEmModel &	operator= (const G4VEmModel &right)=delete
	G4VEmModel (const G4VEmModel &)=delete

Protected Member Functions
virtual G4double	ComputeDXSectionPerAtom (G4double gammaEnergy)
void	SetParticle (const G4ParticleDefinition *p)
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
G4bool	fIsElectron = true
G4bool	fIsScatOffElectron = false
G4bool	fIsLPMActive = false
G4int	fCurrentIZ = 0
const G4ParticleDefinition *	fPrimaryParticle = nullptr
G4ParticleDefinition *	fGammaParticle = nullptr
G4ParticleChangeForLoss *	fParticleChange = nullptr
G4double	fPrimaryParticleMass = 0.
G4double	fPrimaryKinEnergy = 0.
G4double	fPrimaryTotalEnergy = 0.
G4double	fDensityFactor = 0.
G4double	fDensityCorr = 0.
G4double	fLowestKinEnergy
G4double	fNucTerm = 0.
G4double	fSumTerm = 0.
Protected Attributes inherited from G4VEmModel
G4ElementData *	fElementData = nullptr
G4VParticleChange *	pParticleChange = nullptr
G4PhysicsTable *	xSectionTable = nullptr
const G4Material *	pBaseMaterial = nullptr
const std::vector< G4double > *	theDensityFactor = nullptr
const std::vector< G4int > *	theDensityIdx = nullptr
G4double	inveplus
G4double	pFactor = 1.0
std::size_t	currentCoupleIndex = 0
std::size_t	basedCoupleIndex = 0
G4bool	lossFlucFlag = true

Static Protected Attributes
static const G4double	gBremFactor
static const G4double	gMigdalConstant

Detailed Description

Definition at line 59 of file G4eBremsstrahlungRelModel.hh.

Constructor & Destructor Documentation

◆ G4eBremsstrahlungRelModel()

G4eBremsstrahlungRelModel::G4eBremsstrahlungRelModel	(	const G4ParticleDefinition *	p = nullptr,
		const G4String &	nam = "eBremLPM" )

explicit

Definition at line 126 of file G4eBremsstrahlungRelModel.cc.

: G4VEmModel(nam)
{
  fGammaParticle       = G4Gamma::Gamma();
  //
  fLowestKinEnergy     = 1.0*CLHEP::MeV;
  SetLowEnergyLimit(fLowestKinEnergy);
  //
  fLPMEnergyThreshold  = 1.e+39;
  fLPMEnergy           = 0.;
  SetAngularDistribution(new G4ModifiedTsai());
  //
  if (nullptr != p) {
    SetParticle(p);
  }
}

Referenced by G4LivermoreBremsstrahlungModel::G4LivermoreBremsstrahlungModel().

◆ ~G4eBremsstrahlungRelModel()

G4eBremsstrahlungRelModel::~G4eBremsstrahlungRelModel ( )

override

Definition at line 144 of file G4eBremsstrahlungRelModel.cc.

{
  if (fIsInitializer) {
    // clear ElementData container
    for (auto const & ptr : gElementData) { delete ptr; }
    gElementData.clear();
  }
}

Member Function Documentation

◆ ComputeCrossSectionPerAtom()

G4double G4eBremsstrahlungRelModel::ComputeCrossSectionPerAtom	(	const G4ParticleDefinition *	p,
		G4double	ekin,
		G4double	zet,
		G4double	,
		G4double	cutEnergy,
		G4double	maxEnergy = DBL_MAX )

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 320 of file G4eBremsstrahlungRelModel.cc.

{
  G4double crossSection = 0.0;
  if (nullptr == fPrimaryParticle) {
    SetParticle(p);
  }
  if (kineticEnergy < LowEnergyLimit()) {
    return crossSection;
  }
  // min/max kinetic energy limits of the DCS integration:
  const G4double tmin = std::min(cut, kineticEnergy);
  const G4double tmax = std::min(maxEnergy, kineticEnergy);
  // zero restricted x-section if e- kinetic energy is below gamma cut
  if (tmin >= tmax) {
    return crossSection;
  }
  fCurrentIZ = std::min(G4lrint(Z), gMaxZet);
  // integrate numerically (dependent part of) the DCS between the kin. limits:
  // a. integrate between tmin and kineticEnergy of the e-
  crossSection = ComputeXSectionPerAtom(tmin);
  // allow partial integration: only if maxEnergy < kineticEnergy
  // b. integrate between tmax and kineticEnergy (tmax=maxEnergy in this case)
  // (so the result in this case is the integral of DCS between tmin and
  // maxEnergy)
  if (tmax < kineticEnergy) {
    crossSection -= ComputeXSectionPerAtom(tmax);
  }
  // multiply with the constant factors: 16\alpha r_0^2/3 Z^2
  crossSection *= Z*Z*gBremFactor;
  return std::max(crossSection, 0.);
}

◆ ComputeDEDXPerVolume()

G4double G4eBremsstrahlungRelModel::ComputeDEDXPerVolume	(	const G4Material *	material,
		const G4ParticleDefinition *	p,
		G4double	ekin,
		G4double	cutEnergy )

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 237 of file G4eBremsstrahlungRelModel.cc.

{
  G4double dedx = 0.0;
  if (nullptr == fPrimaryParticle) {
    SetParticle(p);
  }
  if (kineticEnergy < LowEnergyLimit()) {
    return dedx;
  }
  // maximum value of the dE/dx integral (the minimum is 0 of course)
  G4double tmax = std::min(cutEnergy, kineticEnergy);
  if (tmax == 0.0) {
    return dedx;
  }
  // sets kinematical and material related variables
  SetupForMaterial(fPrimaryParticle, material,kineticEnergy);
  // get element compositions of the material
  const G4ElementVector* theElemVector = material->GetElementVector();
  const G4double* theAtomNumDensVector = material->GetAtomicNumDensityVector();
  const std::size_t numberOfElements = theElemVector->size();
  // loop over the elements of the material and compute their contributions to
  // the restricted dE/dx by numerical integration of the dependent part of DCS
  for (std::size_t ie = 0; ie < numberOfElements; ++ie) {
    G4VEmModel::SetCurrentElement((*theElemVector)[ie]);
    G4int zet = (*theElemVector)[ie]->GetZasInt();
    fCurrentIZ = std::min(zet, gMaxZet);
    dedx              += (zet*zet)*theAtomNumDensVector[ie]*ComputeBremLoss(tmax);
  }
  // apply the constant factor C/Z = 16\alpha r_0^2/3
  dedx *= gBremFactor;
  return std::max(dedx,0.);
}

◆ ComputeDXSectionPerAtom()

G4double G4eBremsstrahlungRelModel::ComputeDXSectionPerAtom ( G4double gammaEnergy )

protectedvirtual

Reimplemented in G4LivermoreBremsstrahlungModel.

Definition at line 476 of file G4eBremsstrahlungRelModel.cc.

{
  G4double dxsec = 0.0;
  if (gammaEnergy < 0.) {
    return dxsec;
  }
  const G4double y         = gammaEnergy/fPrimaryTotalEnergy;
  const G4double onemy     = 1.-y;
  const G4double dum0      = onemy+0.75*y*y;
  const ElementData* elDat = gElementData[fCurrentIZ];
  // use complete screening and L_el, L_inel from Dirac-Fock model instead of TF
  if (fCurrentIZ < 5 || fIsUseCompleteScreening) {
    dxsec  = dum0*elDat->fZFactor1;
    dxsec += onemy*elDat->fZFactor2;
    if (fIsScatOffElectron) {
      fSumTerm = dxsec;
      fNucTerm = dum0*elDat->fZFactor11+onemy/12.;
    }
  } else {
    // use Tsai's analytical approx. (Tsai Eqs. [3.38-3.41]) to the 'universal'
    // numerical screening functions computed by using the TF model of the atom
    const G4double invZ    = 1./(G4double)fCurrentIZ;
    const G4double Fz      = elDat->fFz;
    const G4double logZ    = elDat->fLogZ;
    const G4double dum1    = y/(fPrimaryTotalEnergy-gammaEnergy);
    const G4double gamma   = dum1*elDat->fGammaFactor;
    const G4double epsilon = dum1*elDat->fEpsilonFactor;
    // evaluate the screening functions
    G4double phi1, phi1m2, psi1, psi1m2;
    ComputeScreeningFunctions(phi1, phi1m2, psi1, psi1m2, gamma, epsilon);
    dxsec  = dum0*((0.25*phi1-Fz) + (0.25*psi1-2.*logZ/3.)*invZ);
    dxsec += 0.125*onemy*(phi1m2 + psi1m2*invZ);
    if (fIsScatOffElectron) {
      fSumTerm = dxsec;
      fNucTerm = dum0*(0.25*phi1-Fz) + 0.125*onemy*phi1m2;
    }
  }
  return std::max(dxsec,0.0);
}

Referenced by SampleSecondaries().

◆ Initialise()

void G4eBremsstrahlungRelModel::Initialise	(	const G4ParticleDefinition *	p,
		const G4DataVector &	cuts )

overridevirtual

Implements G4VEmModel.

Reimplemented in G4LivermoreBremsstrahlungModel.

Definition at line 153 of file G4eBremsstrahlungRelModel.cc.

{
  // parameters in each thread
  if (fPrimaryParticle != p) {
    SetParticle(p);
  }
  fUseLPM = G4EmParameters::Instance()->LPM();
  fCurrentIZ = 0;
 
  // init static element data and precompute LPM functions only once
  std::call_once(applyOnce, [this]() { fIsInitializer = true; });
 
  // for all treads and derived classes
  if (fIsInitializer || gElementData.empty()) {
    G4AutoLock l(&theBremRelMutex);
    if (gElementData.empty()) {
      gElementData.resize(gMaxZet+1, nullptr);
    }
    InitialiseElementData();
    l.unlock();
  }
 
  // element selectors are initialized in the master thread
  if (IsMaster()) {
    InitialiseElementSelectors(p, cuts);
  }
  // initialisation in all threads
  if (nullptr == fParticleChange) {
    fParticleChange = GetParticleChangeForLoss();
  }
  if (GetTripletModel()) {
    GetTripletModel()->Initialise(p, cuts);
    fIsScatOffElectron = true;
  }
}

Referenced by G4LivermoreBremsstrahlungModel::Initialise().

◆ InitialiseLocal()

void G4eBremsstrahlungRelModel::InitialiseLocal	(	const G4ParticleDefinition *	,
		G4VEmModel *	masterModel )

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 190 of file G4eBremsstrahlungRelModel.cc.

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

◆ MinPrimaryEnergy()

G4double G4eBremsstrahlungRelModel::MinPrimaryEnergy	(	const G4Material *	,
		const G4ParticleDefinition *	,
		G4double	cutEnergy )

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 227 of file G4eBremsstrahlungRelModel.cc.

{
  return std::max(fLowestKinEnergy, cut);
}

◆ SampleSecondaries()

void G4eBremsstrahlungRelModel::SampleSecondaries	(	std::vector< G4DynamicParticle * > *	vdp,
		const G4MaterialCutsCouple *	couple,
		const G4DynamicParticle *	dp,
		G4double	cutEnergy,
		G4double	maxEnergy )

overridevirtual

Implements G4VEmModel.

Reimplemented in G4LivermoreBremsstrahlungModel.

Definition at line 540 of file G4eBremsstrahlungRelModel.cc.

{
  const G4double kineticEnergy    = dp->GetKineticEnergy();
  if (kineticEnergy < LowEnergyLimit()) {
    return;
  }
  // min, max kinetic energy limits
  const G4double tmin = std::min(cutEnergy, kineticEnergy);
  const G4double tmax = std::min(maxEnergy, kineticEnergy);
  if (tmin >= tmax) {
    return;
  }
  //
  SetupForMaterial(fPrimaryParticle, couple->GetMaterial(), kineticEnergy);
  const G4Element* elm = SelectTargetAtom(couple,fPrimaryParticle,kineticEnergy,
                                          dp->GetLogKineticEnergy(),tmin,tmax);
  //
  fCurrentIZ = elm->GetZasInt();
  const ElementData* elDat = gElementData[fCurrentIZ];
  const G4double funcMax = elDat->fZFactor1+elDat->fZFactor2;
  // get the random engine
  G4double rndm[2];
  CLHEP::HepRandomEngine* rndmEngine = G4Random::getTheEngine();
  // min max of the transformed variable: x(k) = ln(k^2+k_p^2) that is in [ln(k_c^2+k_p^2), ln(E_k^2+k_p^2)]
  const G4double xmin   = G4Log(tmin*tmin+fDensityCorr);
  const G4double xrange = G4Log(tmax*tmax+fDensityCorr)-xmin;
  G4double gammaEnergy, funcVal;
  do {
    rndmEngine->flatArray(2, rndm);
    gammaEnergy = std::sqrt(std::max(G4Exp(xmin+rndm[0]*xrange)-fDensityCorr, 0.0));
    funcVal     = fIsLPMActive
                 ? ComputeRelDXSectionPerAtom(gammaEnergy)
                 : ComputeDXSectionPerAtom(gammaEnergy);
    // cross-check of proper function maximum in the rejection
//    if (funcVal > funcMax) {
//      G4cout << "### G4eBremsstrahlungRelModel Warning: Majoranta exceeded! "
//       << funcVal << " > " << funcMax
//       << " Egamma(MeV)= " << gammaEnergy
//       << " Ee(MeV)= " << kineticEnergy
//       << "  " << GetName()
//       << G4endl;
//    }
    // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
  } while (funcVal < funcMax*rndm[1]);
  //
  // scattering off nucleus or off e- by triplet model
  if (fIsScatOffElectron && rndmEngine->flat()*fSumTerm>fNucTerm) {
    GetTripletModel()->SampleSecondaries(vdp, couple, dp, cutEnergy, maxEnergy);
    return;
  }
  //
  // angles of the emitted gamma. ( Z - axis along the parent particle)
  // use general interface
  G4ThreeVector gamDir =
    GetAngularDistribution()->SampleDirection(dp,fPrimaryTotalEnergy-gammaEnergy,
                                              fCurrentIZ, couple->GetMaterial());
  // create G4DynamicParticle object for the Gamma
  auto gamma = new G4DynamicParticle(fGammaParticle, gamDir, gammaEnergy);
  vdp->push_back(gamma);
  // compute post-interaction kinematics of primary e-/e+ based on
  // energy-momentum conservation
  const G4double totMomentum = std::sqrt(kineticEnergy*(
                               fPrimaryTotalEnergy + CLHEP::electron_mass_c2));
  G4ThreeVector dir =
             (totMomentum*dp->GetMomentumDirection()-gammaEnergy*gamDir).unit();
  const G4double finalE   = kineticEnergy-gammaEnergy;
  // if secondary gamma energy is higher than threshold(very high by default)
  // then stop tracking the primary particle and create new secondary e-/e+
  // instead of the primary one
  if (gammaEnergy > SecondaryThreshold()) {
    fParticleChange->ProposeTrackStatus(fStopAndKill);
    fParticleChange->SetProposedKineticEnergy(0.0);
    auto el = new G4DynamicParticle(
              const_cast<G4ParticleDefinition*>(fPrimaryParticle), dir, finalE);
    vdp->push_back(el);
  } else { // continue tracking the primary e-/e+ otherwise
    fParticleChange->SetProposedMomentumDirection(dir);
    fParticleChange->SetProposedKineticEnergy(finalE);
  }
}

◆ SetParticle()

void G4eBremsstrahlungRelModel::SetParticle ( const G4ParticleDefinition * p )

protected

Definition at line 196 of file G4eBremsstrahlungRelModel.cc.

{
  fPrimaryParticle     = p;
  fPrimaryParticleMass = p->GetPDGMass();
  fIsElectron          = (p==G4Electron::Electron());
}

Referenced by ComputeCrossSectionPerAtom(), ComputeDEDXPerVolume(), G4eBremsstrahlungRelModel(), and Initialise().

◆ SetupForMaterial()

void G4eBremsstrahlungRelModel::SetupForMaterial	(	const G4ParticleDefinition *	,
		const G4Material *	mat,
		G4double	kineticEnergy )

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 206 of file G4eBremsstrahlungRelModel.cc.

{
  fDensityFactor = gMigdalConstant*mat->GetElectronDensity();
  fLPMEnergy     = gLPMconstant*mat->GetRadlen();
  // threshold for LPM effect (i.e. below which LPM hidden by density effect)
  if (fUseLPM) {
    fLPMEnergyThreshold = std::sqrt(fDensityFactor)*fLPMEnergy;
  } else {
    fLPMEnergyThreshold = 1.e+39;   // i.e. do not use LPM effect
  }
  // calculate threshold for density effect: k_p = sqrt(fDensityCorr)
  fPrimaryKinEnergy   = kineticEnergy;
  fPrimaryTotalEnergy = kineticEnergy+fPrimaryParticleMass;
  fDensityCorr        = fDensityFactor*fPrimaryTotalEnergy*fPrimaryTotalEnergy;
  // set activation flag for LPM effects in the DCS
  fIsLPMActive = (fPrimaryTotalEnergy>fLPMEnergyThreshold);
}