#include <G4MuPairProductionModel.hh>

Inheritance diagram for G4MuPairProductionModel:

Public Member Functions
	G4MuPairProductionModel (const G4ParticleDefinition *p=0, const G4String &nam="muPairProd")

virtual	~G4MuPairProductionModel ()

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

virtual void	InitialiseLocal (const G4ParticleDefinition , G4VEmModel masterModel)

virtual G4double	ComputeCrossSectionPerAtom (const G4ParticleDefinition *, G4double kineticEnergy, G4double Z, G4double A, G4double cutEnergy, G4double maxEnergy)

virtual G4double	ComputeDEDXPerVolume (const G4Material , const G4ParticleDefinition , G4double kineticEnergy, G4double cutEnergy)

virtual void	SampleSecondaries (std::vector< G4DynamicParticle * > , const G4MaterialCutsCouple , const G4DynamicParticle *, G4double tmin, G4double maxEnergy)

virtual G4double	MinPrimaryEnergy (const G4Material , const G4ParticleDefinition , G4double)

void	SetLowestKineticEnergy (G4double e)

void	SetParticle (const G4ParticleDefinition *)

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	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	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 Member Functions
G4double	ComputMuPairLoss (G4double Z, G4double tkin, G4double cut, G4double tmax)

G4double	ComputeMicroscopicCrossSection (G4double tkin, G4double Z, G4double cut)

virtual G4double	ComputeDMicroscopicCrossSection (G4double tkin, G4double Z, G4double pairEnergy)

G4double	MaxSecondaryEnergyForElement (G4double kineticEnergy, G4double Z)

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
const G4ParticleDefinition *	particle

G4NistManager *	nist

G4double	factorForCross

G4double	sqrte

G4double	particleMass

G4double	z13

G4double	z23

G4double	lnZ

G4int	currentZ

Protected Attributes inherited from G4VEmModel
G4ElementData *	fElementData

G4VParticleChange *	pParticleChange

G4PhysicsTable *	xSectionTable

const std::vector< G4double > *	theDensityFactor

const std::vector< G4int > *	theDensityIdx

size_t	idxTable

Static Protected Attributes
static const G4double	xgi [8]

static const G4double	wgi [8]

Detailed Description

Definition at line 73 of file G4MuPairProductionModel.hh.

Constructor & Destructor Documentation

G4MuPairProductionModel::G4MuPairProductionModel	(	const G4ParticleDefinition *	p = `0`,
		const G4String &	nam = `"muPairProd"`
	)

Definition at line 104 of file G4MuPairProductionModel.cc.

References G4Electron::Electron(), G4ParticleDefinition::GetPDGMass(), G4NistManager::Instance(), lnZ, nist, particleMass, G4Positron::Positron(), SetParticle(), python.hepunit::TeV, z13, and z23.

   : G4VEmModel(nam),
     particle(0),
     factorForCross(4.*fine_structure_const*fine_structure_const
                    *classic_electr_radius*classic_electr_radius/(3.*pi)),
     sqrte(sqrt(G4Exp(1.))),
     currentZ(0),
     fParticleChange(0),
     minPairEnergy(4.*electron_mass_c2),
     lowestKinEnergy(1.0*GeV),
     nzdat(5),
     nYBinPerDecade(4),
     nbiny(1000),
     nbine(0),
     ymin(-5.),
     dy(0.005)
 {
   nist = G4NistManager::Instance();
 
   theElectron = G4Electron::Electron();
   thePositron = G4Positron::Positron();
 
   particleMass = lnZ = z13 = z23 = 0;
 
   // setup lowest limit dependent on particle mass
   if(p) { 
     SetParticle(p); 
     G4double limit = p->GetPDGMass()*8;
     if(limit > lowestKinEnergy) { lowestKinEnergy = limit; }
   }
   emin = lowestKinEnergy;
   emax = 10*TeV;
 }

G4MuPairProductionModel::~G4MuPairProductionModel ( )

virtual

Definition at line 141 of file G4MuPairProductionModel.cc.

142 {}

Member Function Documentation

G4double G4MuPairProductionModel::ComputeCrossSectionPerAtom	(	const G4ParticleDefinition *	,
		G4double	kineticEnergy,
		G4double	Z,
		G4double	A,
		G4double	cutEnergy,
		G4double	maxEnergy
	)

virtual

Reimplemented from G4VEmModel.

Definition at line 415 of file G4MuPairProductionModel.cc.

References ComputeMicroscopicCrossSection(), G4INCL::Math::max(), MaxSecondaryEnergyForElement(), and G4INCL::Math::min().

 {
   G4double cross = 0.0;
   if (kineticEnergy <= lowestKinEnergy) { return cross; }
 
   G4double maxPairEnergy = MaxSecondaryEnergyForElement(kineticEnergy, Z);
   G4double tmax = std::min(maxEnergy, maxPairEnergy);
   G4double cut  = std::max(cutEnergy, minPairEnergy);
   if (cut >= tmax) { return cross; }
 
   cross = ComputeMicroscopicCrossSection(kineticEnergy, Z, cut);
   if(tmax < kineticEnergy) {
     cross -= ComputeMicroscopicCrossSection(kineticEnergy, Z, tmax);
   }
   return cross;
 }

G4double G4MuPairProductionModel::ComputeDEDXPerVolume	(	const G4Material *	material,
		const G4ParticleDefinition *	,
		G4double	kineticEnergy,
		G4double	cutEnergy
	)

virtual

Reimplemented from G4VEmModel.

Definition at line 196 of file G4MuPairProductionModel.cc.

References ComputMuPairLoss(), G4Material::GetAtomicNumDensityVector(), G4Material::GetElementVector(), G4Material::GetNumberOfElements(), and MaxSecondaryEnergyForElement().

 {
   G4double dedx = 0.0;
   if (cutEnergy <= minPairEnergy || kineticEnergy <= lowestKinEnergy)
     { return dedx; }
 
   const G4ElementVector* theElementVector = material->GetElementVector();
   const G4double* theAtomicNumDensityVector =
                                    material->GetAtomicNumDensityVector();
 
   //  loop for elements in the material
   for (size_t i=0; i<material->GetNumberOfElements(); ++i) {
      G4double Z = (*theElementVector)[i]->GetZ();
      G4double tmax = MaxSecondaryEnergyForElement(kineticEnergy, Z);
      G4double loss = ComputMuPairLoss(Z, kineticEnergy, cutEnergy, tmax);
      dedx += loss*theAtomicNumDensityVector[i];
   }
   if (dedx < 0.) { dedx = 0.; }
   return dedx;
 }

G4double G4MuPairProductionModel::ComputeDMicroscopicCrossSection	(	G4double	tkin,
		G4double	Z,
		G4double	pairEnergy
	)

protectedvirtual

Reimplemented in G4hPairProductionModel.

Definition at line 302 of file G4MuPairProductionModel.cc.

References python.hepunit::electron_mass_c2, factorForCross, fe, fm, G4Exp(), G4Log(), particleMass, sqrte, wgi, xgi, G4InuclParticleNames::xi0, z13, and z23.

Referenced by ComputeMicroscopicCrossSection(), and ComputMuPairLoss().

 {
   static const G4double bbbtf= 183. ;
   static const G4double bbbh = 202.4 ;
   static const G4double g1tf = 1.95e-5 ;
   static const G4double g2tf = 5.3e-5 ;
   static const G4double g1h  = 4.4e-5 ;
   static const G4double g2h  = 4.8e-5 ;
 
   G4double totalEnergy  = tkin + particleMass;
   G4double residEnergy  = totalEnergy - pairEnergy;
   G4double massratio    = particleMass/electron_mass_c2 ;
   G4double massratio2   = massratio*massratio ;
   G4double cross = 0.;
 
   G4double c3 = 0.75*sqrte*particleMass;
   if (residEnergy <= c3*z13) { return cross; }
 
   G4double c7 = 4.*CLHEP::electron_mass_c2;
   G4double c8 = 6.*particleMass*particleMass;
   G4double alf = c7/pairEnergy;
   G4double a3 = 1. - alf;
   if (a3 <= 0.) { return cross; }
 
   // zeta calculation
   G4double bbb,g1,g2;
   if( Z < 1.5 ) { bbb = bbbh ; g1 = g1h ; g2 = g2h ; }
   else          { bbb = bbbtf; g1 = g1tf; g2 = g2tf; }
 
   G4double zeta = 0;
   G4double zeta1 = 
     0.073*G4Log(totalEnergy/(particleMass+g1*z23*totalEnergy))-0.26;
   if ( zeta1 > 0.)
   {
     G4double zeta2 = 
       0.058*G4Log(totalEnergy/(particleMass+g2*z13*totalEnergy))-0.14;
     zeta  = zeta1/zeta2 ;
   }
 
   G4double z2 = Z*(Z+zeta);
   G4double screen0 = 2.*electron_mass_c2*sqrte*bbb/(z13*pairEnergy);
   G4double a0 = totalEnergy*residEnergy;
   G4double a1 = pairEnergy*pairEnergy/a0;
   G4double bet = 0.5*a1;
   G4double xi0 = 0.25*massratio2*a1;
   G4double del = c8/a0;
 
   G4double rta3 = sqrt(a3);
   G4double tmnexp = alf/(1. + rta3) + del*rta3;
   if(tmnexp >= 1.0) { return cross; }
 
   G4double tmn = G4Log(tmnexp);
   G4double sum = 0.;
 
   // Gaussian integration in ln(1-ro) ( with 8 points)
   for (G4int i=0; i<8; ++i)
   {
     G4double a4 = G4Exp(tmn*xgi[i]);     // a4 = (1.-asymmetry)
     G4double a5 = a4*(2.-a4) ;
     G4double a6 = 1.-a5 ;
     G4double a7 = 1.+a6 ;
     G4double a9 = 3.+a6 ;
     G4double xi = xi0*a5 ;
     G4double xii = 1./xi ;
     G4double xi1 = 1.+xi ;
     G4double screen = screen0*xi1/a5 ;
     G4double yeu = 5.-a6+4.*bet*a7 ;
     G4double yed = 2.*(1.+3.*bet)*G4Log(3.+xii)-a6-a1*(2.-a6) ;
     G4double ye1 = 1.+yeu/yed ;
     G4double ale = G4Log(bbb/z13*sqrt(xi1*ye1)/(1.+screen*ye1)) ;
     G4double cre = 0.5*G4Log(1.+2.25*z23*xi1*ye1/massratio2) ;
     G4double be;
 
     if (xi <= 1.e3) { 
       be = ((2.+a6)*(1.+bet)+xi*a9)*G4Log(1.+xii)+(a5-bet)/xi1-a9;
     } else {           
       be = (3.-a6+a1*a7)/(2.*xi);
     }
     G4double fe = (ale-cre)*be;
     if ( fe < 0.) fe = 0. ;
 
     G4double ymu = 4.+a6 +3.*bet*a7 ;
     G4double ymd = a7*(1.5+a1)*G4Log(3.+xi)+1.-1.5*a6 ;
     G4double ym1 = 1.+ymu/ymd ;
     G4double alm_crm = G4Log(bbb*massratio/(1.5*z23*(1.+screen*ym1)));
     G4double a10,bm;
     if ( xi >= 1.e-3)
     {
       a10 = (1.+a1)*a5 ;
       bm  = (a7*(1.+1.5*bet)-a10*xii)*G4Log(xi1)+xi*(a5-bet)/xi1+a10;
     } else {
       bm = (5.-a6+bet*a9)*(xi/2.);
     }
 
     G4double fm = alm_crm*bm;
     if ( fm < 0.) { fm = 0.; }
 
     sum += wgi[i]*a4*(fe+fm/massratio2);
   }
 
   cross = -tmn*sum*factorForCross*z2*residEnergy/(totalEnergy*pairEnergy);
   if(cross < 0.0) { cross = 0.0; }
   return cross;
 }

G4double G4MuPairProductionModel::ComputeMicroscopicCrossSection	(	G4double	tkin,
		G4double	Z,
		G4double	cut
	)

protected

Definition at line 264 of file G4MuPairProductionModel.cc.

References ComputeDMicroscopicCrossSection(), G4Exp(), G4Log(), G4INCL::Math::max(), MaxSecondaryEnergyForElement(), wgi, test::x, and xgi.

Referenced by ComputeCrossSectionPerAtom().

 {
   G4double cross = 0.;
   G4double tmax = MaxSecondaryEnergyForElement(tkin, Z);
   G4double cut  = std::max(cutEnergy, minPairEnergy);
   if (tmax <= cut) { return cross; }
 
   G4double ak1=6.9 ;
   G4double ak2=1.0 ;
   G4double aaa = G4Log(cut);
   G4double bbb = G4Log(tmax);
   G4int kkk = (G4int)((bbb-aaa)/ak1 + ak2);
   if(kkk > 8) { kkk = 8; }
   else if (kkk < 1) { kkk = 1; }
 
   G4double hhh = (bbb-aaa)/G4double(kkk);
   G4double x = aaa;
 
   for(G4int l=0; l<kkk; ++l)
   {
     for(G4int i=0; i<8; ++i)
     {
       G4double ep = G4Exp(x + xgi[i]*hhh);
       cross += ep*wgi[i]*ComputeDMicroscopicCrossSection(tkin, Z, ep);
     }
     x += hhh;
   }
 
   cross *= hhh;
   if(cross < 0.0) { cross = 0.0; }
   return cross;
 }

G4double G4MuPairProductionModel::ComputMuPairLoss	(	G4double	Z,
		G4double	tkin,
		G4double	cut,
		G4double	tmax
	)

protected

Definition at line 223 of file G4MuPairProductionModel.cc.

References ComputeDMicroscopicCrossSection(), G4Exp(), G4Log(), G4INCL::Math::min(), wgi, test::x, and xgi.

Referenced by ComputeDEDXPerVolume().

 {
   G4double loss = 0.0;
 
   G4double cut = std::min(cutEnergy,tmax);
   if(cut <= minPairEnergy) { return loss; }
 
   // calculate the rectricted loss
   // numerical integration in log(PairEnergy)
   G4double ak1=6.9;
   G4double ak2=1.0;
   G4double aaa = G4Log(minPairEnergy);
   G4double bbb = G4Log(cut);
 
   G4int    kkk = (G4int)((bbb-aaa)/ak1+ak2);
   if (kkk > 8)      { kkk = 8; }
   else if (kkk < 1) { kkk = 1; }
 
   G4double hhh = (bbb-aaa)/(G4double)kkk;
   G4double x = aaa;
 
   for (G4int l=0 ; l<kkk; l++)
   {
 
     for (G4int ll=0; ll<8; ll++)
     {
       G4double ep = G4Exp(x+xgi[ll]*hhh);
       loss += wgi[ll]*ep*ep*ComputeDMicroscopicCrossSection(tkin, Z, ep);
     }
     x += hhh;
   }
   loss *= hhh;
   if (loss < 0.) loss = 0.;
   return loss;
 }

void G4MuPairProductionModel::Initialise	(	const G4ParticleDefinition *	p,
		const G4DataVector &	cuts
	)

virtual

Implements G4VEmModel.

Definition at line 155 of file G4MuPairProductionModel.cc.

References G4VEmModel::fElementData, G4Log(), G4VEmModel::GetParticleChangeForLoss(), G4VEmModel::HighEnergyLimit(), G4VEmModel::InitialiseElementSelectors(), G4VEmModel::IsMaster(), G4VEmModel::LowEnergyLimit(), G4INCL::Math::max(), particle, and SetParticle().

 { 
   SetParticle(p); 
 
   // define scale of internal table for each thread only once
   if(0 == nbine) {
     emax = HighEnergyLimit();
     emin = std::max(lowestKinEnergy, LowEnergyLimit());
     nbine = size_t(nYBinPerDecade*std::log10(emax/emin));
     if(nbine < 3) { nbine = 3; }
 
     ymin = G4Log(minPairEnergy/emin);
     dy   = -ymin/G4double(nbiny);
   }
 
   if(IsMaster() && p == particle) { 
     
     if(!fElementData) { 
       fElementData = new G4ElementData();
       MakeSamplingTables(); 
     }    
     InitialiseElementSelectors(p, cuts); 
   }
 
   if(!fParticleChange) { fParticleChange = GetParticleChangeForLoss(); }
 }

void G4MuPairProductionModel::InitialiseLocal	(	const G4ParticleDefinition *	p,
		G4VEmModel *	masterModel
	)

virtual

Reimplemented from G4VEmModel.

Definition at line 185 of file G4MuPairProductionModel.cc.

References G4VEmModel::fElementData, G4VEmModel::GetElementData(), G4VEmModel::GetElementSelectors(), particle, and G4VEmModel::SetElementSelectors().

 {
   if(p == particle) {
     SetElementSelectors(masterModel->GetElementSelectors());
     fElementData = masterModel->GetElementData();
   }
 }

G4double G4MuPairProductionModel::MaxSecondaryEnergyForElement	(	G4double	kineticEnergy,
		G4double	Z
	)

inlineprotected

Definition at line 202 of file G4MuPairProductionModel.hh.

References currentZ, G4lrint(), G4NistManager::GetLOGZ(), G4NistManager::GetZ13(), lnZ, nist, particleMass, sqrte, z13, and z23.

Referenced by ComputeCrossSectionPerAtom(), ComputeDEDXPerVolume(), ComputeMicroscopicCrossSection(), and SampleSecondaries().

 {
   G4int Z = G4lrint(ZZ);
   if(Z != currentZ) {
     currentZ = Z;
     z13 = nist->GetZ13(Z);
     z23 = z13*z13;
     lnZ = nist->GetLOGZ(Z);
   }
   return kineticEnergy + particleMass*(1.0 - 0.75*sqrte*z13);
 }

G4double G4MuPairProductionModel::MinPrimaryEnergy	(	const G4Material *	,
		const G4ParticleDefinition *	,
		G4double	cut
	)

virtual

Reimplemented from G4VEmModel.

Definition at line 146 of file G4MuPairProductionModel.cc.

References G4INCL::Math::max().

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

void G4MuPairProductionModel::SampleSecondaries	(	std::vector< G4DynamicParticle * > *	vdp,
		const G4MaterialCutsCouple *	couple,
		const G4DynamicParticle *	aDynamicParticle,
		G4double	tmin,
		G4double	maxEnergy
	)

virtual

Implements G4VEmModel.

Definition at line 508 of file G4MuPairProductionModel.cc.

References currentZ, python.hepunit::electron_mass_c2, G4Exp(), G4Log(), G4UniformRand, G4InuclParticleNames::gam, G4DynamicParticle::GetKineticEnergy(), G4NistManager::GetLOGZ(), G4DynamicParticle::GetMomentum(), G4DynamicParticle::GetMomentumDirection(), G4Element::GetZ(), iz, lnZ, G4INCL::Math::max(), MaxSecondaryEnergyForElement(), python.hepunit::MeV, G4INCL::Math::min(), nist, particle, particleMass, CLHEP::Hep3Vector::rotateUz(), G4VEmModel::SelectRandomAtom(), G4ParticleChangeForLoss::SetProposedKineticEnergy(), G4ParticleChangeForLoss::SetProposedMomentumDirection(), python.hepunit::twopi, CLHEP::Hep3Vector::unit(), and test::x.

 {
   G4double kineticEnergy = aDynamicParticle->GetKineticEnergy();
   //G4cout << "------- G4MuPairProductionModel::SampleSecondaries E(MeV)= " 
   //     << kineticEnergy << "  " 
   //     << aDynamicParticle->GetDefinition()->GetParticleName() << G4endl;
   G4double totalEnergy   = kineticEnergy + particleMass;
   G4double totalMomentum = 
     sqrt(kineticEnergy*(kineticEnergy + 2.0*particleMass));
 
   G4ThreeVector partDirection = aDynamicParticle->GetMomentumDirection();
 
   // select randomly one element constituing the material
   const G4Element* anElement = SelectRandomAtom(couple,particle,kineticEnergy);
 
   // define interval of energy transfer
   G4double maxPairEnergy = MaxSecondaryEnergyForElement(kineticEnergy, 
                             anElement->GetZ());
   G4double maxEnergy     = std::min(tmax, maxPairEnergy);
   G4double minEnergy     = std::max(tmin, minPairEnergy);
 
   if(minEnergy >= maxEnergy) { return; }
   //G4cout << "emin= " << minEnergy << " emax= " << maxEnergy 
   // << " minPair= " << minPairEnergy << " maxpair= " << maxPairEnergy 
   //    << " ymin= " << ymin << " dy= " << dy << G4endl;
 
   G4double coeff = G4Log(minPairEnergy/kineticEnergy)/ymin;
 
   // compute limits 
   G4double yymin = G4Log(minEnergy/kineticEnergy)/coeff;
   G4double yymax = G4Log(maxEnergy/kineticEnergy)/coeff;
  
   //G4cout << "yymin= " << yymin << "  yymax= " << yymax << G4endl;
 
   // units should not be used, bacause table was built without
   G4double logTkin = G4Log(kineticEnergy/MeV);
 
   // sample e-e+ energy, pair energy first
 
   // select sample table via Z
   G4int iz1(0), iz2(0);
   for(G4int iz=0; iz<nzdat; ++iz) { 
     if(currentZ == zdat[iz]) {
       iz1 = iz2 = currentZ; 
       break;
     } else if(currentZ < zdat[iz]) {
       iz2 = zdat[iz];
       if(iz > 0) { iz1 = zdat[iz-1]; }
       else { iz1 = iz2; }
       break;
     } 
   }
   if(0 == iz1) { iz1 = iz2 = zdat[nzdat-1]; }
 
   G4double PairEnergy = 0.0;
   G4int count = 0;
   //G4cout << "start loop Z1= " << iz1 << " Z2= " << iz2 << G4endl;
   do {
     ++count;
     // sampling using only one random number
     G4double rand = G4UniformRand();
   
     G4double x = FindScaledEnergy(iz1, rand, logTkin, yymin, yymax);
     if(iz1 != iz2) {
       G4double x2 = FindScaledEnergy(iz2, rand, logTkin, yymin, yymax);
       G4double lz1= nist->GetLOGZ(iz1);
       G4double lz2= nist->GetLOGZ(iz2);
       //G4cout << count << ".  x= " << x << "  x2= " << x2 
       //         << " Z1= " << iz1 << " Z2= " << iz2 << G4endl;
       x += (x2 - x)*(lnZ - lz1)/(lz2 - lz1);
     }
     //G4cout << "x= " << x << "  coeff= " << coeff << G4endl;
     PairEnergy = kineticEnergy*G4Exp(x*coeff);
     
   } while((PairEnergy < minEnergy || PairEnergy > maxEnergy) && 10 > count);
 
   //G4cout << "## PairEnergy(GeV)= " << PairEnergy/GeV 
   //     << " Etot(GeV)= " << totalEnergy/GeV << G4endl; 
 
   // sample r=(E+-E-)/PairEnergy  ( uniformly .....)
   G4double rmax =
     (1.-6.*particleMass*particleMass/(totalEnergy*(totalEnergy-PairEnergy)))
                                        *sqrt(1.-minPairEnergy/PairEnergy);
   G4double r = rmax * (-1.+2.*G4UniformRand()) ;
 
   // compute energies from PairEnergy,r
   G4double ElectronEnergy = (1.-r)*PairEnergy*0.5;
   G4double PositronEnergy = PairEnergy - ElectronEnergy;
 
   // The angle of the emitted virtual photon is sampled
   // according to the muon bremsstrahlung model
  
   G4double gam  = totalEnergy/particleMass;
   G4double gmax = gam*std::min(1.0, totalEnergy/PairEnergy - 1.0);
   G4double gmax2= gmax*gmax;
   G4double x = G4UniformRand()*gmax2/(1.0 + gmax2);
 
   G4double theta = sqrt(x/(1.0 - x))/gam;
   G4double sint  = sin(theta);
   G4double phi   = twopi * G4UniformRand() ;
   G4double dirx  = sint*cos(phi), diry = sint*sin(phi), dirz = cos(theta) ;
 
   G4ThreeVector gDirection(dirx, diry, dirz);
   gDirection.rotateUz(partDirection);
 
   // the angles of e- and e+ assumed to be the same as virtual gamma
 
   // create G4DynamicParticle object for the particle1
   G4DynamicParticle* aParticle1 = 
     new G4DynamicParticle(theElectron, gDirection, 
               ElectronEnergy - electron_mass_c2);
 
   // create G4DynamicParticle object for the particle2
   G4DynamicParticle* aParticle2 = 
     new G4DynamicParticle(thePositron, gDirection,
               PositronEnergy - electron_mass_c2);
 
   // primary change
   kineticEnergy -= (ElectronEnergy + PositronEnergy);
   fParticleChange->SetProposedKineticEnergy(kineticEnergy);
 
   partDirection *= totalMomentum;
   partDirection -= (aParticle1->GetMomentum() + aParticle2->GetMomentum());
   partDirection = partDirection.unit();
   fParticleChange->SetProposedMomentumDirection(partDirection);
 
   // add secondary
   vdp->push_back(aParticle1);
   vdp->push_back(aParticle2);
   //G4cout << "-- G4MuPairProductionModel::SampleSecondaries done" << G4endl; 
 }

void G4MuPairProductionModel::SetLowestKineticEnergy ( G4double e )

inline

Definition at line 183 of file G4MuPairProductionModel.hh.

 {
   lowestKinEnergy = e;
 }

void G4MuPairProductionModel::SetParticle ( const G4ParticleDefinition * p )

inline

Definition at line 191 of file G4MuPairProductionModel.hh.

References G4ParticleDefinition::GetPDGMass(), particle, and particleMass.

Referenced by G4MuPairProductionModel(), and Initialise().

 {
   if(!particle) {
     particle = p;
     particleMass = particle->GetPDGMass();
   }
 }

Field Documentation

G4int G4MuPairProductionModel::currentZ

protected

Definition at line 153 of file G4MuPairProductionModel.hh.

Referenced by MaxSecondaryEnergyForElement(), and SampleSecondaries().

G4double G4MuPairProductionModel::factorForCross

protected

Definition at line 147 of file G4MuPairProductionModel.hh.

Referenced by G4hPairProductionModel::ComputeDMicroscopicCrossSection(), and ComputeDMicroscopicCrossSection().

G4double G4MuPairProductionModel::lnZ

protected

Definition at line 152 of file G4MuPairProductionModel.hh.

Referenced by G4MuPairProductionModel(), MaxSecondaryEnergyForElement(), and SampleSecondaries().

G4NistManager* G4MuPairProductionModel::nist

protected

Definition at line 145 of file G4MuPairProductionModel.hh.

Referenced by G4MuPairProductionModel(), MaxSecondaryEnergyForElement(), and SampleSecondaries().

const G4ParticleDefinition* G4MuPairProductionModel::particle

protected

Definition at line 144 of file G4MuPairProductionModel.hh.

Referenced by Initialise(), InitialiseLocal(), SampleSecondaries(), and SetParticle().

G4double G4MuPairProductionModel::particleMass

protected

Definition at line 149 of file G4MuPairProductionModel.hh.

Referenced by G4hPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), G4MuPairProductionModel(), MaxSecondaryEnergyForElement(), SampleSecondaries(), and SetParticle().

G4double G4MuPairProductionModel::sqrte

protected

Definition at line 148 of file G4MuPairProductionModel.hh.

Referenced by G4hPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), and MaxSecondaryEnergyForElement().

const G4double G4MuPairProductionModel::wgi

staticprotected

Initial value:

={ 0.0506, 0.1112, 0.1569, 0.1813,

0.1813, 0.1569, 0.1112, 0.0506 }

Definition at line 155 of file G4MuPairProductionModel.hh.

Referenced by G4hPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), ComputeMicroscopicCrossSection(), and ComputMuPairLoss().

const G4double G4MuPairProductionModel::xgi

staticprotected

Initial value:

={ 0.0199, 0.1017, 0.2372, 0.4083,

0.5917, 0.7628, 0.8983, 0.9801 }

Definition at line 155 of file G4MuPairProductionModel.hh.

Referenced by G4hPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), ComputeMicroscopicCrossSection(), and ComputMuPairLoss().

G4double G4MuPairProductionModel::z13

protected

Definition at line 150 of file G4MuPairProductionModel.hh.

Referenced by G4hPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), G4MuPairProductionModel(), and MaxSecondaryEnergyForElement().

G4double G4MuPairProductionModel::z23

protected

Definition at line 151 of file G4MuPairProductionModel.hh.

Referenced by G4hPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), G4MuPairProductionModel(), and MaxSecondaryEnergyForElement().

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

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Field Documentation