#include <G4KleinNishinaModel.hh>

Inheritance diagram for G4KleinNishinaModel:

Public Member Functions
	G4KleinNishinaModel (const G4String &nam="KleinNishina")

virtual	~G4KleinNishinaModel ()

virtual void	Initialise (const G4ParticleDefinition *, const G4DataVector &)

virtual G4double	ComputeCrossSectionPerAtom (const G4ParticleDefinition *, G4double kinEnergy, G4double Z, G4double A, G4double cut, G4double emax)

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
G4ParticleDefinition *	theGamma

G4ParticleDefinition *	theElectron

G4ParticleChangeForGamma *	fParticleChange

G4double	lowestGammaEnergy

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 59 of file G4KleinNishinaModel.hh.

Constructor & Destructor Documentation

◆ G4KleinNishinaModel()

G4KleinNishinaModel::G4KleinNishinaModel ( const G4String & nam = "KleinNishina" )

Definition at line 65 of file G4KleinNishinaModel.cc.

  : G4VEmModel(nam)
{
  theGamma = G4Gamma::Gamma();
  theElectron = G4Electron::Electron();
  lowestGammaEnergy = 1.0*eV;
  limitFactor       = 4;
  fProbabilities.resize(9,0.0);
  SetDeexcitationFlag(true);
  fParticleChange = 0;
  fAtomDeexcitation = 0;
}

◆ ~G4KleinNishinaModel()

G4KleinNishinaModel::~G4KleinNishinaModel ( )

virtual

Definition at line 80 of file G4KleinNishinaModel.cc.

81{}

Member Function Documentation

◆ ComputeCrossSectionPerAtom()

G4double G4KleinNishinaModel::ComputeCrossSectionPerAtom	(	const G4ParticleDefinition *	,
		G4double	kinEnergy,
		G4double	Z,
		G4double	A,
		G4double	cut,
		G4double	emax
	)

virtual

Reimplemented from G4VEmModel.

Definition at line 96 of file G4KleinNishinaModel.cc.

{
  G4double xSection = 0.0 ;
  if ( Z < 0.9999 || GammaEnergy < 0.1*keV) { return xSection; }
 
  static const G4double a = 20.0 , b = 230.0 , c = 440.0;
  
  static const G4double
    d1= 2.7965e-1*barn, d2=-1.8300e-1*barn, d3= 6.7527   *barn, d4=-1.9798e+1*barn,
    e1= 1.9756e-5*barn, e2=-1.0205e-2*barn, e3=-7.3913e-2*barn, e4= 2.7079e-2*barn,
    f1=-3.9178e-7*barn, f2= 6.8241e-5*barn, f3= 6.0480e-5*barn, f4= 3.0274e-4*barn;
     
  G4double p1Z = Z*(d1 + e1*Z + f1*Z*Z), p2Z = Z*(d2 + e2*Z + f2*Z*Z),
           p3Z = Z*(d3 + e3*Z + f3*Z*Z), p4Z = Z*(d4 + e4*Z + f4*Z*Z);
 
  G4double T0  = 15.0*keV; 
  if (Z < 1.5) { T0 = 40.0*keV; } 
 
  G4double X   = max(GammaEnergy, T0) / electron_mass_c2;
  xSection = p1Z*std::log(1.+2.*X)/X
               + (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
        
  //  modification for low energy. (special case for Hydrogen)
  if (GammaEnergy < T0) {
    G4double dT0 = keV;
    X = (T0+dT0) / electron_mass_c2 ;
    G4double sigma = p1Z*log(1.+2*X)/X
                    + (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
    G4double   c1 = -T0*(sigma-xSection)/(xSection*dT0);             
    G4double   c2 = 0.150; 
    if (Z > 1.5) { c2 = 0.375-0.0556*log(Z); }
    G4double    y = log(GammaEnergy/T0);
    xSection *= exp(-y*(c1+c2*y));          
  }
 
  if(xSection < 0.0) { xSection = 0.0; }
  //  G4cout << "e= " << GammaEnergy << " Z= " << Z 
  //  << " cross= " << xSection << G4endl;
  return xSection;
}

◆ Initialise()

void G4KleinNishinaModel::Initialise	(	const G4ParticleDefinition *	p,
		const G4DataVector &	cuts
	)

virtual

Implements G4VEmModel.

Definition at line 85 of file G4KleinNishinaModel.cc.

{
  fAtomDeexcitation = G4LossTableManager::Instance()->AtomDeexcitation();
  InitialiseElementSelectors(p, cuts);
  if(!fParticleChange) { fParticleChange = GetParticleChangeForGamma(); }
}

◆ SampleSecondaries()

void G4KleinNishinaModel::SampleSecondaries	(	std::vector< G4DynamicParticle * > *	fvect,
		const G4MaterialCutsCouple *	couple,
		const G4DynamicParticle *	aDynamicGamma,
		G4double	tmin,
		G4double	maxEnergy
	)

virtual

Implements G4VEmModel.

Definition at line 142 of file G4KleinNishinaModel.cc.

{
  // primary gamma
  G4double energy = aDynamicGamma->GetKineticEnergy();
  G4ThreeVector direction = aDynamicGamma->GetMomentumDirection();
 
  // select atom
  const G4Element* elm = SelectRandomAtom(couple, theGamma, energy);
 
  // select shell first
  G4int nShells = elm->GetNbOfAtomicShells();
  if(nShells > (G4int)fProbabilities.size()) { fProbabilities.resize(nShells); }
  G4double totprob = 0.0;
  G4int i;
  for(i=0; i<nShells; ++i) {
    //G4double bindingEnergy = elm->GetAtomicShell(i);
    totprob += elm->GetNbOfShellElectrons(i);
    //totprob += elm->GetNbOfShellElectrons(i)/(bindingEnergy*bindingEnergy);
    fProbabilities[i] = totprob; 
  }
  //if(totprob == 0.0) { return; }
 
  // Loop on sampling
  //  const G4int nlooplim = 100;
  //G4int nloop = 0;
 
  G4double bindingEnergy, ePotEnergy, eKinEnergy;
  G4double gamEnergy0, gamEnergy1;
 
  //static const G4double eminus2 =  1.0 - exp(-2.0);
 
  do {
    //++nloop;
    G4double xprob = totprob*G4UniformRand();
 
    // select shell
    for(i=0; i<nShells; ++i) { if(xprob <= fProbabilities[i]) { break; } }
   
    bindingEnergy = elm->GetAtomicShell(i);
    //    ePotEnergy    = bindingEnergy;
    //    gamEnergy0 = energy;
    lv1.set(0.0,0.0,energy,energy);
 
    //G4cout << "nShells= " << nShells << " i= " << i 
    //   << " Egamma= " << energy << " Ebind= " << bindingEnergy
    //   << " Elim= " << limitEnergy 
    //   << G4endl;
 
    // for rest frame of the electron
    G4double x = -log(G4UniformRand());
    eKinEnergy = bindingEnergy*x;
    ePotEnergy = bindingEnergy*(1.0 + x);
 
    // for rest frame of the electron
    G4double eTotMomentum = sqrt(eKinEnergy*(eKinEnergy + 2*electron_mass_c2));
    G4double phi = G4UniformRand()*twopi;
    G4double costet = 2*G4UniformRand() - 1;
    G4double sintet = sqrt((1 - costet)*(1 + costet));
    lv2.set(eTotMomentum*sintet*cos(phi),eTotMomentum*sintet*sin(phi),
        eTotMomentum*costet,eKinEnergy + electron_mass_c2);
    bst = lv2.boostVector();
    lv1.boost(-bst);
 
    gamEnergy0 = lv1.e();
   
    // In the rest frame of the electron
    // 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). 
    G4double E0_m = gamEnergy0/electron_mass_c2;
 
    //
    // sample the energy rate of the scattered gamma 
    //
 
    G4double epsilon, epsilonsq, onecost, sint2, greject ;
 
    G4double eps0       = 1./(1 + 2*E0_m);
    G4double epsilon0sq = eps0*eps0;
    G4double alpha1     = - log(eps0);
    G4double alpha2     = 0.5*(1 - epsilon0sq);
 
    do {
      if ( alpha1/(alpha1+alpha2) > G4UniformRand() ) {
    epsilon   = exp(-alpha1*G4UniformRand());   // epsilon0**r
    epsilonsq = epsilon*epsilon; 
 
      } else {
    epsilonsq = epsilon0sq + (1.- epsilon0sq)*G4UniformRand();
    epsilon   = sqrt(epsilonsq);
      }
 
      onecost = (1.- epsilon)/(epsilon*E0_m);
      sint2   = onecost*(2.-onecost);
      greject = 1. - epsilon*sint2/(1.+ epsilonsq);
 
    } while (greject < G4UniformRand());
    gamEnergy1 = epsilon*gamEnergy0;
 
    // before scattering total 4-momentum in e- system
    lv2.set(0.0,0.0,0.0,electron_mass_c2);
    lv2 += lv1;
 
    //
    // scattered gamma angles. ( Z - axis along the parent gamma)
    //
    if(sint2 < 0.0) { sint2 = 0.0; }
    costet = 1. - onecost; 
    sintet = sqrt(sint2);
    phi  = twopi * G4UniformRand();
 
    // e- recoil
    //
    // in  rest frame of the electron
    G4ThreeVector gamDir = lv1.vect().unit();
    G4ThreeVector v = G4ThreeVector(sintet*cos(phi),sintet*sin(phi),costet);
    v.rotateUz(gamDir);
    lv1.set(gamEnergy1*v.x(),gamEnergy1*v.y(),gamEnergy1*v.z(),gamEnergy1);
    lv2 -= lv1;
    //G4cout<<"Egam= "<<lv1.e()<<" Ee= "<< lv2.e()-electron_mass_c2 << G4endl;
    lv2.boost(bst);
    eKinEnergy = lv2.e() - electron_mass_c2 - ePotEnergy;   
    //G4cout << "eKinEnergy= " << eKinEnergy << G4endl;
 
  } while ( eKinEnergy < 0.0 );
 
  //
  // update G4VParticleChange for the scattered gamma
  //
   
  lv1.boost(bst);
  gamEnergy1 = lv1.e();
  if(gamEnergy1 > lowestGammaEnergy) {
    G4ThreeVector gamDirection1 = lv1.vect().unit();
    gamDirection1.rotateUz(direction);
    fParticleChange->ProposeMomentumDirection(gamDirection1);
  } else { 
    fParticleChange->ProposeTrackStatus(fStopAndKill);
    gamEnergy1 = 0.0;
  }
  fParticleChange->SetProposedKineticEnergy(gamEnergy1);
 
  //
  // kinematic of the scattered electron
  //
 
  if(eKinEnergy > lowestGammaEnergy) {
    G4ThreeVector eDirection = lv2.vect().unit();
    eDirection.rotateUz(direction);
    G4DynamicParticle* dp = 
      new G4DynamicParticle(theElectron,eDirection,eKinEnergy);
    fvect->push_back(dp);
  } else { eKinEnergy = 0.0; }
 
  G4double edep = energy - gamEnergy1 - eKinEnergy;
  
  // sample deexcitation
  //
  if(fAtomDeexcitation) {
    G4int index = couple->GetIndex();
    if(fAtomDeexcitation->CheckDeexcitationActiveRegion(index)) {
      G4int Z = G4lrint(elm->GetZ());
      G4AtomicShellEnumerator as = G4AtomicShellEnumerator(i);
      const G4AtomicShell* shell = fAtomDeexcitation->GetAtomicShell(Z, as);
      size_t nbefore = fvect->size();
      fAtomDeexcitation->GenerateParticles(fvect, shell, Z, index);
      size_t nafter = fvect->size();
      if(nafter > nbefore) {
    for (size_t j=nbefore; j<nafter; ++j) {
      edep -= ((*fvect)[j])->GetKineticEnergy();
    } 
      }
    }
  }
  // energy balance
  if(edep < 0.0) { edep = 0.0; }
  fParticleChange->ProposeLocalEnergyDeposit(edep);
}

Member Data Documentation

◆ fParticleChange

G4ParticleChangeForGamma* G4KleinNishinaModel::fParticleChange

protected

Definition at line 88 of file G4KleinNishinaModel.hh.

Referenced by G4KleinNishinaModel(), Initialise(), and SampleSecondaries().

◆ lowestGammaEnergy

G4double G4KleinNishinaModel::lowestGammaEnergy

protected

Definition at line 89 of file G4KleinNishinaModel.hh.

Referenced by G4KleinNishinaModel(), and SampleSecondaries().

◆ theElectron

G4ParticleDefinition* G4KleinNishinaModel::theElectron

protected

Definition at line 87 of file G4KleinNishinaModel.hh.

Referenced by G4KleinNishinaModel(), and SampleSecondaries().

◆ theGamma

G4ParticleDefinition* G4KleinNishinaModel::theGamma

protected

Definition at line 86 of file G4KleinNishinaModel.hh.

Referenced by G4KleinNishinaModel(), 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

◆ G4KleinNishinaModel()

◆ ~G4KleinNishinaModel()

Member Function Documentation

◆ ComputeCrossSectionPerAtom()

◆ Initialise()

◆ SampleSecondaries()

Member Data Documentation

◆ fParticleChange

◆ lowestGammaEnergy

◆ theElectron

◆ theGamma