#include <G4MuPairProductionModel.hh>

Inheritance diagram for G4MuPairProductionModel:

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

	~G4MuPairProductionModel () override=default

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

void	InitialiseLocal (const G4ParticleDefinition , G4VEmModel masterModel) override

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

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

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

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

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

void	SetLowestKineticEnergy (G4double e)

void	SetParticle (const G4ParticleDefinition *)

G4MuPairProductionModel &	operator= (const G4MuPairProductionModel &right)=delete

	G4MuPairProductionModel (const G4MuPairProductionModel &)=delete

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 G4MaterialCutsCouple , const G4DynamicParticle , const G4double &length, G4double &eloss)

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 *)

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

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

G4double	FindScaledEnergy (G4int Z, G4double rand, G4double logTkin, G4double yymin, G4double yymax)

G4double	MaxSecondaryEnergyForElement (G4double kineticEnergy, G4double Z)

void	MakeSamplingTables ()

void	StoreTables () const

G4bool	RetrieveTables ()

virtual void	DataCorrupted (G4int Z, G4double logTkin) const

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
G4ParticleChangeForLoss *	fParticleChange = nullptr

const G4ParticleDefinition *	particle = nullptr

G4NistManager *	nist = nullptr

G4double	factorForCross

G4double	sqrte

G4double	particleMass = 0.0

G4double	z13 = 0.0

G4double	z23 = 0.0

G4double	lnZ = 0.0

G4double	minPairEnergy

G4double	lowestKinEnergy

G4double	emin

G4double	emax

G4double	ymin = -5.0

G4double	dy = 0.005

G4int	currentZ = 0

G4int	nYBinPerDecade = 4

std::size_t	nbiny = 1000

std::size_t	nbine = 0

G4bool	fTableToFile = false

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 G4int	NZDATPAIR = 5

static const G4int	NINTPAIR = 8

static const G4int	ZDATPAIR [NZDATPAIR] = {1, 4, 13, 29, 92}

static const G4double	xgi [NINTPAIR]

static const G4double	wgi [NINTPAIR]

Detailed Description

Definition at line 72 of file G4MuPairProductionModel.hh.

Constructor & Destructor Documentation

◆ G4MuPairProductionModel() [1/2]

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

explicit

Definition at line 118 of file G4MuPairProductionModel.cc.

  : G4VEmModel(nam),
  factorForCross(CLHEP::fine_structure_const*CLHEP::fine_structure_const*
         CLHEP::classic_electr_radius*CLHEP::classic_electr_radius*
         4./(3.*CLHEP::pi)),
  sqrte(std::sqrt(G4Exp(1.))),
  minPairEnergy(4.*CLHEP::electron_mass_c2),
  lowestKinEnergy(0.85*CLHEP::GeV)
{
  nist = G4NistManager::Instance();
 
  theElectron = G4Electron::Electron();
  thePositron = G4Positron::Positron();
 
  if(nullptr != p) { 
    SetParticle(p); 
    lowestKinEnergy = std::max(lowestKinEnergy, p->GetPDGMass()*8.0);  
  }
  emin = lowestKinEnergy;
  emax = emin*10000.;
  SetAngularDistribution(new G4ModifiedMephi());
}

Referenced by G4hPairProductionModel::G4hPairProductionModel(), G4MuonToMuonPairProductionModel::G4MuonToMuonPairProductionModel(), G4MuPairProductionModel(), and operator=().

◆ ~G4MuPairProductionModel()

G4MuPairProductionModel::~G4MuPairProductionModel ( )

overridedefault

◆ G4MuPairProductionModel() [2/2]

G4MuPairProductionModel::G4MuPairProductionModel ( const G4MuPairProductionModel & )

delete

Member Function Documentation

◆ ComputeCrossSectionPerAtom()

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

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 457 of file G4MuPairProductionModel.cc.

{
  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;
}

◆ ComputeDEDXPerVolume()

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

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 229 of file G4MuPairProductionModel.cc.

{
  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 (std::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];
  }
  dedx = std::max(dedx, 0.0);
  return dedx;
}

◆ ComputeDMicroscopicCrossSection()

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

virtual

Reimplemented in G4MuonToMuonPairProductionModel.

Definition at line 321 of file G4MuPairProductionModel.cc.

{
  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 ;
 
  if (pairEnergy <= minPairEnergy)
    return 0.0;
 
  G4double totalEnergy  = tkin + particleMass;
  G4double residEnergy  = totalEnergy - pairEnergy;
 
  if (residEnergy <= 0.75*sqrte*z13*particleMass)
    return 0.0;
 
  G4double a0 = 1.0 / (totalEnergy * residEnergy);
  G4double alf = 4.0 * electron_mass_c2 / pairEnergy;
  G4double rt = std::sqrt(1.0 - alf);
  G4double delta = 6.0 * particleMass * particleMass * a0;
  G4double tmnexp = alf/(1.0 + rt) + delta*rt;
 
  if(tmnexp >= 1.0) { return 0.0; }
 
  G4double tmn = G4Log(tmnexp);
 
  G4double massratio = particleMass/CLHEP::electron_mass_c2;
  G4double massratio2 = massratio*massratio;
  G4double inv_massratio2 = 1.0 / massratio2;
 
  // 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 = 0.0;
  G4double z1exp = totalEnergy / (particleMass + g1*z23*totalEnergy);
 
  // 35.221047195922 is the root of zeta1(x) = 0.073 * log(x) - 0.26, so the
  // condition below is the same as zeta1 > 0.0, but without calling log(x)
  if (z1exp > 35.221047195922)
  {
    G4double z2exp = totalEnergy / (particleMass + g2*z13*totalEnergy);
    zeta = (0.073 * G4Log(z1exp) - 0.26) / (0.058 * G4Log(z2exp) - 0.14);
  }
 
  G4double z2 = Z*(Z+zeta);
  G4double screen0 = 2.*electron_mass_c2*sqrte*bbb/(z13*pairEnergy);
  G4double beta = 0.5*pairEnergy*pairEnergy*a0;
  G4double xi0 = 0.5*massratio2*beta;
 
  // Gaussian integration in ln(1-ro) ( with 8 points)
  G4double rho[NINTPAIR];
  G4double rho2[NINTPAIR];
  G4double xi[NINTPAIR];
  G4double xi1[NINTPAIR];
  G4double xii[NINTPAIR];
 
  for (G4int i = 0; i < NINTPAIR; ++i)
  {
    rho[i] = G4Exp(tmn*xgi[i]) - 1.0; // rho = -asymmetry
    rho2[i] = rho[i] * rho[i];
    xi[i] = xi0*(1.0-rho2[i]);
    xi1[i] = 1.0 + xi[i];
    xii[i] = 1.0 / xi[i];
  }
 
  G4double ye1[NINTPAIR];
  G4double ym1[NINTPAIR];
 
  G4double b40 = 4.0 * beta;
  G4double b62 = 6.0 * beta + 2.0;
 
  for (G4int i = 0; i < NINTPAIR; ++i)
  {
    G4double yeu = (b40 + 5.0) + (b40 - 1.0) * rho2[i];
    G4double yed = b62*G4Log(3.0 + xii[i]) + (2.0 * beta - 1.0)*rho2[i] - b40;
 
    G4double ymu = b62 * (1.0 + rho2[i]) + 6.0;
    G4double ymd = (b40 + 3.0)*(1.0 + rho2[i])*G4Log(3.0 + xi[i])
      + 2.0 - 3.0 * rho2[i];
 
    ye1[i] = 1.0 + yeu / yed;
    ym1[i] = 1.0 + ymu / ymd;
  }
 
  G4double be[NINTPAIR];
  G4double bm[NINTPAIR];
 
  for(G4int i = 0; i < NINTPAIR; ++i) {
    if(xi[i] <= 1000.0) {
      be[i] = ((2.0 + rho2[i])*(1.0 + beta) +
           xi[i]*(3.0 + rho2[i]))*G4Log(1.0 + xii[i]) +
    (1.0 - rho2[i] - beta)/xi1[i] - (3.0 + rho2[i]);
    } else {
      be[i] = 0.5*(3.0 - rho2[i] + 2.0*beta*(1.0 + rho2[i]))*xii[i];
    }
 
    if(xi[i] >= 0.001) {
      G4double a10 = (1.0 + 2.0 * beta) * (1.0 - rho2[i]);
      bm[i] = ((1.0 + rho2[i])*(1.0 + 1.5 * beta) - a10*xii[i])*G4Log(xi1[i]) +
                xi[i] * (1.0 - rho2[i] - beta)/xi1[i] + a10;
    } else {
      bm[i] = 0.5*(5.0 - rho2[i] + beta * (3.0 + rho2[i]))*xi[i];
    }
  }
 
  G4double sum = 0.0;
 
  for (G4int i = 0; i < NINTPAIR; ++i) {
    G4double screen = screen0*xi1[i]/(1.0 - rho2[i]);
    G4double ale = G4Log(bbb/z13*std::sqrt(xi1[i]*ye1[i])/(1. + screen*ye1[i]));
    G4double cre = 0.5*G4Log(1. + 2.25*z23*xi1[i]*ye1[i]*inv_massratio2);
 
    G4double fe = (ale-cre)*be[i];
    fe = std::max(fe, 0.0);
 
    G4double alm_crm = G4Log(bbb*massratio/(1.5*z23*(1. + screen*ym1[i])));
    G4double fm = std::max(alm_crm*bm[i], 0.0)*inv_massratio2;
 
    sum += wgi[i]*(1.0 + rho[i])*(fe + fm);
  }
 
  return -tmn*sum*factorForCross*z2*residEnergy/(totalEnergy*pairEnergy);
}

Referenced by ComputeMicroscopicCrossSection(), ComputMuPairLoss(), and MakeSamplingTables().

◆ ComputeMicroscopicCrossSection()

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

protected

Definition at line 289 of file G4MuPairProductionModel.cc.

{
  G4double cross = 0.;
  G4double tmax = MaxSecondaryEnergyForElement(tkin, Z);
  G4double cut  = std::max(cutEnergy, minPairEnergy);
  if (tmax <= cut) { return cross; }
 
  G4double aaa = G4Log(cut);
  G4double bbb = G4Log(tmax);
  G4int kkk = std::min(std::max(G4lrint((bbb-aaa)/ak1 + ak2), 8), 1);
 
  G4double hhh = (bbb-aaa)/(kkk);
  G4double x = aaa;
 
  for (G4int l=0; l<kkk; ++l) {
    for (G4int i=0; i<NINTPAIR; ++i) {
      G4double ep = G4Exp(x + xgi[i]*hhh);
      cross += ep*wgi[i]*ComputeDMicroscopicCrossSection(tkin, Z, ep);
    }
    x += hhh;
  }
 
  cross *= hhh;
  cross = std::max(cross, 0.0);
  return cross;
}

Referenced by ComputeCrossSectionPerAtom().

◆ ComputMuPairLoss()

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

protected

Definition at line 256 of file G4MuPairProductionModel.cc.

{
  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 aaa = G4Log(minPairEnergy);
  G4double bbb = G4Log(cut);
 
  G4int kkk = std::min(std::max(G4lrint((bbb-aaa)/ak1 + ak2), 8), 1);
  G4double hhh = (bbb-aaa)/kkk;
  G4double x = aaa;
 
  for (G4int l=0 ; l<kkk; ++l) {
    for (G4int ll=0; ll<NINTPAIR; ++ll) {
      G4double ep = G4Exp(x+xgi[ll]*hhh);
      loss += wgi[ll]*ep*ep*ComputeDMicroscopicCrossSection(tkin, Z, ep);
    }
    x += hhh;
  }
  loss *= hhh;
  loss = std::max(loss, 0.0);
  return loss;
}

Referenced by ComputeDEDXPerVolume().

◆ DataCorrupted()

void G4MuPairProductionModel::DataCorrupted	(	G4int	Z,
		G4double	logTkin ) const

protectedvirtual

Reimplemented in G4MuonToMuonPairProductionModel.

Definition at line 703 of file G4MuPairProductionModel.cc.

{
  G4ExceptionDescription ed;
  ed << "G4ElementData is not properly initialized Z= " << Z
     << " Ekin(MeV)= " << G4Exp(logTkin)
     << " IsMasterThread= " << IsMaster() 
     << " Model " << GetName();
  G4Exception("G4MuPairProductionModel::()", "em0033", FatalException, ed, "");
}

Referenced by FindScaledEnergy(), and StoreTables().

◆ FindScaledEnergy()

G4double G4MuPairProductionModel::FindScaledEnergy	(	G4int	Z,
		G4double	rand,
		G4double	logTkin,
		G4double	yymin,
		G4double	yymax )

protected

Definition at line 683 of file G4MuPairProductionModel.cc.

{
  G4double res = yymin;
  G4Physics2DVector* pv = fElementData->GetElement2DData(iz);
  if (nullptr != pv) { 
    G4double pmin = pv->Value(yymin, logTkin);
    G4double pmax = pv->Value(yymax, logTkin);
    G4double p0   = pv->Value(0.0, logTkin);
    if(p0 <= 0.0) { DataCorrupted(ZDATPAIR[iz], logTkin); }
    else { res = pv->FindLinearX((pmin + rand*(pmax - pmin))/p0, logTkin); }
  } else {
    DataCorrupted(ZDATPAIR[iz], logTkin); 
  }
  return res;
}

Referenced by G4MuonToMuonPairProductionModel::SampleSecondaries(), and SampleSecondaries().

◆ Initialise()

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

overridevirtual

Implements G4VEmModel.

Definition at line 153 of file G4MuPairProductionModel.cc.

{ 
  SetParticle(p); 
 
  if (nullptr == fParticleChange) { 
    fParticleChange = GetParticleChangeForLoss();
 
    // define scale of internal table for each thread only once
    if (0 == nbine) {
      emin = std::max(lowestKinEnergy, LowEnergyLimit());
      emax = std::max(HighEnergyLimit(), emin*2);
      nbine = std::size_t(nYBinPerDecade*std::log10(emax/emin));
      if(nbine < 3) { nbine = 3; }
 
      ymin = G4Log(minPairEnergy/emin);
      dy = -ymin/G4double(nbiny);
    }
    if (p == particle) {
      G4int pdg = std::abs(p->GetPDGEncoding());
      if (pdg == 2212) {
    dataName = "pEEPairProd";
      } else if (pdg == 321) {
    dataName = "kaonEEPairProd";
      } else if (pdg == 211) {
    dataName = "pionEEPairProd";
      } else if (pdg == 11) {
    dataName = "eEEPairProd";
      } else if (pdg == 13) {
        if (GetName() == "muToMuonPairProd") {
          dataName = "muMuMuPairProd";
    } else {
      dataName = "muEEPairProd";
    }
      } 
    }
  }
 
  // for low-energy application this process should not work
  if(lowestKinEnergy >= HighEnergyLimit()) { return; }
 
  if (p == particle) {
    fElementData =
      G4ElementDataRegistry::Instance()->GetElementDataByName(dataName);
    if (nullptr == fElementData) { 
      G4AutoLock l(&theMuPairMutex);
      fElementData =
    G4ElementDataRegistry::Instance()->GetElementDataByName(dataName);
      if (nullptr == fElementData) { 
    fElementData = new G4ElementData(NZDATPAIR);
    fElementData->SetName(dataName);
      }
      G4bool useDataFile = G4EmParameters::Instance()->RetrieveMuDataFromFile();
      if (useDataFile)  { useDataFile = RetrieveTables(); }
      if (!useDataFile) { MakeSamplingTables(); }
      if (fTableToFile) { StoreTables(); }
      l.unlock();
    }
    if (IsMaster()) {
      InitialiseElementSelectors(p, cuts);
    }
  }
}

◆ InitialiseLocal()

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

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 219 of file G4MuPairProductionModel.cc.

{
  if(p == particle && lowestKinEnergy < HighEnergyLimit()) {
    SetElementSelectors(masterModel->GetElementSelectors());
  }
}

◆ MakeSamplingTables()

void G4MuPairProductionModel::MakeSamplingTables ( )

protected

Definition at line 481 of file G4MuPairProductionModel.cc.

{
  G4double factore = G4Exp(G4Log(emax/emin)/G4double(nbine));
 
  for (G4int iz=0; iz<NZDATPAIR; ++iz) {
 
    G4double Z = ZDATPAIR[iz];
    G4Physics2DVector* pv = new G4Physics2DVector(nbiny+1,nbine+1);
    G4double kinEnergy = emin;
 
    for (std::size_t it=0; it<=nbine; ++it) {
 
      pv->PutY(it, G4Log(kinEnergy/CLHEP::MeV));
      G4double maxPairEnergy = MaxSecondaryEnergyForElement(kinEnergy, Z);
      /*
      G4cout << "it= " << it << " E= " << kinEnergy 
             << "  " << particle->GetParticleName()   
             << " maxE= " << maxPairEnergy << "  minE= " << minPairEnergy 
             << " ymin= " << ymin << G4endl;
      */
      G4double coef = G4Log(minPairEnergy/kinEnergy)/ymin;
      G4double ymax = G4Log(maxPairEnergy/kinEnergy)/coef;
      G4double fac  = (ymax - ymin)/dy;
      std::size_t imax   = (std::size_t)fac;
      fac -= (G4double)imax;
   
      G4double xSec = 0.0;
      G4double x = ymin;
      /*
      G4cout << "Z= " << currentZ << " z13= " << z13 
             << " mE= " << maxPairEnergy << "  ymin= " << ymin 
             << " dy= " << dy << "  c= " << coef << G4endl;
      */
      // start from zero
      pv->PutValue(0, it, 0.0);
      if(0 == it) { pv->PutX(nbiny, 0.0); }
 
      for (std::size_t i=0; i<nbiny; ++i) {
 
        if(0 == it) { pv->PutX(i, x); }
 
        if(i < imax) {
          G4double ep = kinEnergy*G4Exp(coef*(x + dy*0.5));
 
          // not multiplied by interval, because table 
          // will be used only for sampling
          //G4cout << "i= " << i << " x= " << x << "E= " << kinEnergy  
          //         << " Egamma= " << ep << G4endl;
          xSec += ep*ComputeDMicroscopicCrossSection(kinEnergy, Z, ep);
 
          // last bin before the kinematic limit
        } else if(i == imax) {
          G4double ep = kinEnergy*G4Exp(coef*(x + fac*dy*0.5));
          xSec += ep*fac*ComputeDMicroscopicCrossSection(kinEnergy, Z, ep);
        }
        pv->PutValue(i + 1, it, xSec);
        x += dy;
      } 
      kinEnergy *= factore;
 
      // to avoid precision lost
      if(it+1 == nbine) { kinEnergy = emax; }
    }
    fElementData->InitialiseForElement(iz, pv);
  }
}

Referenced by Initialise().

◆ MaxSecondaryEnergyForElement()

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

inlineprotected

Definition at line 204 of file G4MuPairProductionModel.hh.

{
  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);
}

Referenced by ComputeCrossSectionPerAtom(), ComputeDEDXPerVolume(), ComputeMicroscopicCrossSection(), MakeSamplingTables(), G4MuonToMuonPairProductionModel::SampleSecondaries(), and SampleSecondaries().

◆ MinPrimaryEnergy()

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

overridevirtual

Reimplemented from G4VEmModel.

Definition at line 144 of file G4MuPairProductionModel.cc.

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

◆ operator=()

G4MuPairProductionModel & G4MuPairProductionModel::operator= ( const G4MuPairProductionModel & right )

delete

◆ RetrieveTables()

G4bool G4MuPairProductionModel::RetrieveTables ( )

protected

Definition at line 733 of file G4MuPairProductionModel.cc.

{
  for (G4int iz=0; iz<NZDATPAIR; ++iz) {
    G4double Z = ZDATPAIR[iz];
    G4Physics2DVector* pv = new G4Physics2DVector(nbiny+1,nbine+1);
    std::ostringstream ss;
    ss << G4EmParameters::Instance()->GetDirLEDATA() << "/mupair/"
       << particle->GetParticleName() << Z << ".dat";
    std::ifstream infile(ss.str(), std::ios::in);
    if(!pv->Retrieve(infile)) { 
      delete pv;
      return false; 
    }
    fElementData->InitialiseForElement(iz, pv);
  }
  return true;
}

Referenced by Initialise().

◆ SampleSecondaries()

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

overridevirtual

Implements G4VEmModel.

Definition at line 550 of file G4MuPairProductionModel.cc.

{
  G4double kinEnergy = aDynamicParticle->GetKineticEnergy();
  //G4cout << "------- G4MuPairProductionModel::SampleSecondaries E(MeV)= " 
  //         << kinEnergy << "  " 
  //         << aDynamicParticle->GetDefinition()->GetParticleName() << G4endl;
  G4double totalEnergy   = kinEnergy + particleMass;
  G4double totalMomentum = 
    std::sqrt(kinEnergy*(kinEnergy + 2.0*particleMass));
 
  G4ThreeVector partDirection = aDynamicParticle->GetMomentumDirection();
 
  // select randomly one element constituing the material
  const G4Element* anElement = SelectRandomAtom(couple,particle,kinEnergy);
 
  // define interval of energy transfer
  G4double maxPairEnergy = MaxSecondaryEnergyForElement(kinEnergy, 
                                                        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/kinEnergy)/ymin;
 
  // compute limits 
  G4double yymin = G4Log(minEnergy/kinEnergy)/coeff;
  G4double yymax = G4Log(maxEnergy/kinEnergy)/coeff;
 
  //G4cout << "yymin= " << yymin << "  yymax= " << yymax << G4endl;
 
  // units should not be used, bacause table was built without
  G4double logTkin = G4Log(kinEnergy/CLHEP::MeV);
 
  // sample e-e+ energy, pair energy first
 
  // select sample table via Z
  G4int iz1(0), iz2(0);
  for (G4int iz=0; iz<NZDATPAIR; ++iz) { 
    if(currentZ == ZDATPAIR[iz]) {
      iz1 = iz2 = iz; 
      break;
    } else if(currentZ < ZDATPAIR[iz]) {
      iz2 = iz;
      if(iz > 0) { iz1 = iz-1; }
      else { iz1 = iz2; }
      break;
    } 
  }
  if (0 == iz1) { iz1 = iz2 = NZDATPAIR-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(ZDATPAIR[iz1]);
      G4double lz2= nist->GetLOGZ(ZDATPAIR[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 = kinEnergy*G4Exp(x*coeff);
    
    // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
  } 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)))
    *std::sqrt(1.-minPairEnergy/pairEnergy);
  G4double r = rmax * (-1.+2.*G4UniformRand()) ;
 
  // compute energies from pairEnergy,r
  G4double eEnergy = (1.-r)*pairEnergy*0.5;
  G4double pEnergy = pairEnergy - eEnergy;
 
  // Sample angles 
  G4ThreeVector eDirection, pDirection;
  //
  GetAngularDistribution()->SamplePairDirections(aDynamicParticle, 
                                                 eEnergy, pEnergy,
                                                 eDirection, pDirection);
  // create G4DynamicParticle object for e+e-
  eEnergy = std::max(eEnergy - CLHEP::electron_mass_c2, 0.0);
  pEnergy = std::max(pEnergy - CLHEP::electron_mass_c2, 0.0);
  auto aParticle1 = new G4DynamicParticle(theElectron,eDirection,eEnergy);
  auto aParticle2 = new G4DynamicParticle(thePositron,pDirection,pEnergy);
  // Fill output vector
  vdp->push_back(aParticle1);
  vdp->push_back(aParticle2);
 
  // primary change
  kinEnergy -= pairEnergy;
  partDirection *= totalMomentum;
  partDirection -= (aParticle1->GetMomentum() + aParticle2->GetMomentum());
  partDirection = partDirection.unit();
 
  // if energy transfer is higher than threshold (very high by default)
  // then stop tracking the primary particle and create a new secondary
  if (pairEnergy > SecondaryThreshold()) {
    fParticleChange->ProposeTrackStatus(fStopAndKill);
    fParticleChange->SetProposedKineticEnergy(0.0);
    auto newdp = new G4DynamicParticle(particle, partDirection, kinEnergy);
    vdp->push_back(newdp);
  } else { // continue tracking the primary e-/e+ otherwise
    fParticleChange->SetProposedMomentumDirection(partDirection);
    fParticleChange->SetProposedKineticEnergy(kinEnergy);
  }
  //G4cout << "-- G4MuPairProductionModel::SampleSecondaries done" << G4endl; 
}

◆ SetLowestKineticEnergy()

void G4MuPairProductionModel::SetLowestKineticEnergy ( G4double e )

inline

Definition at line 185 of file G4MuPairProductionModel.hh.

{
  lowestKinEnergy = e;
}

Referenced by G4ePairProduction::InitialiseEnergyLossProcess().

◆ SetParticle()

void G4MuPairProductionModel::SetParticle ( const G4ParticleDefinition * p )

inline

Definition at line 193 of file G4MuPairProductionModel.hh.

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

Referenced by G4MuPairProductionModel(), and Initialise().

◆ StoreTables()

void G4MuPairProductionModel::StoreTables ( ) const

protected

Definition at line 715 of file G4MuPairProductionModel.cc.

{
  for (G4int iz=0; iz<NZDATPAIR; ++iz) {
    G4int Z = ZDATPAIR[iz];
    G4Physics2DVector* pv = fElementData->GetElement2DData(Z);
    if(nullptr == pv) { 
      DataCorrupted(Z, 1.0);
      return;
    }
    std::ostringstream ss;
    ss << "mupair/" << particle->GetParticleName() << Z << ".dat";
    std::ofstream outfile(ss.str());
    pv->Store(outfile);
  }
}

Referenced by Initialise().

Member Data Documentation

◆ currentZ

G4int G4MuPairProductionModel::currentZ = 0

protected

Definition at line 162 of file G4MuPairProductionModel.hh.

Referenced by MaxSecondaryEnergyForElement(), G4MuonToMuonPairProductionModel::SampleSecondaries(), and SampleSecondaries().

◆ dy

G4double G4MuPairProductionModel::dy = 0.005

protected

Definition at line 160 of file G4MuPairProductionModel.hh.

Referenced by Initialise(), and MakeSamplingTables().

◆ emax

G4double G4MuPairProductionModel::emax

protected

Definition at line 158 of file G4MuPairProductionModel.hh.

Referenced by G4MuPairProductionModel(), Initialise(), and MakeSamplingTables().

◆ emin

G4double G4MuPairProductionModel::emin

protected

Definition at line 157 of file G4MuPairProductionModel.hh.

Referenced by G4MuPairProductionModel(), Initialise(), and MakeSamplingTables().

◆ factorForCross

G4double G4MuPairProductionModel::factorForCross

protected

Definition at line 147 of file G4MuPairProductionModel.hh.

Referenced by ComputeDMicroscopicCrossSection(), and G4MuPairProductionModel().

◆ fParticleChange

G4ParticleChangeForLoss* G4MuPairProductionModel::fParticleChange = nullptr

protected

Definition at line 143 of file G4MuPairProductionModel.hh.

Referenced by Initialise(), G4MuonToMuonPairProductionModel::SampleSecondaries(), and SampleSecondaries().

◆ fTableToFile

G4bool G4MuPairProductionModel::fTableToFile = false

protected

Definition at line 167 of file G4MuPairProductionModel.hh.

Referenced by Initialise().

◆ lnZ

G4double G4MuPairProductionModel::lnZ = 0.0

protected

Definition at line 152 of file G4MuPairProductionModel.hh.

Referenced by MaxSecondaryEnergyForElement(), G4MuonToMuonPairProductionModel::SampleSecondaries(), and SampleSecondaries().

◆ lowestKinEnergy

G4double G4MuPairProductionModel::lowestKinEnergy

protected

Definition at line 155 of file G4MuPairProductionModel.hh.

Referenced by ComputeCrossSectionPerAtom(), ComputeDEDXPerVolume(), G4MuPairProductionModel(), Initialise(), InitialiseLocal(), MinPrimaryEnergy(), and SetLowestKineticEnergy().

◆ minPairEnergy

G4double G4MuPairProductionModel::minPairEnergy

protected

Definition at line 154 of file G4MuPairProductionModel.hh.

Referenced by ComputeCrossSectionPerAtom(), ComputeDEDXPerVolume(), ComputeDMicroscopicCrossSection(), ComputeMicroscopicCrossSection(), ComputMuPairLoss(), G4MuPairProductionModel(), Initialise(), MakeSamplingTables(), and SampleSecondaries().

◆ nbine

std::size_t G4MuPairProductionModel::nbine = 0

protected

Definition at line 165 of file G4MuPairProductionModel.hh.

Referenced by Initialise(), MakeSamplingTables(), and RetrieveTables().

◆ nbiny

std::size_t G4MuPairProductionModel::nbiny = 1000

protected

Definition at line 164 of file G4MuPairProductionModel.hh.

Referenced by Initialise(), MakeSamplingTables(), and RetrieveTables().

◆ NINTPAIR

const G4int G4MuPairProductionModel::NINTPAIR = 8

staticprotected

Definition at line 171 of file G4MuPairProductionModel.hh.

Referenced by G4MuonToMuonPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), ComputeMicroscopicCrossSection(), and ComputMuPairLoss().

◆ nist

G4NistManager* G4MuPairProductionModel::nist = nullptr

protected

Definition at line 145 of file G4MuPairProductionModel.hh.

Referenced by G4MuPairProductionModel(), MaxSecondaryEnergyForElement(), G4MuonToMuonPairProductionModel::SampleSecondaries(), SampleSecondaries(), and G4MuonToMuonPairProductionModel::U_func().

◆ nYBinPerDecade

G4int G4MuPairProductionModel::nYBinPerDecade = 4

protected

Definition at line 163 of file G4MuPairProductionModel.hh.

Referenced by Initialise().

◆ NZDATPAIR

const G4int G4MuPairProductionModel::NZDATPAIR = 5

staticprotected

Definition at line 170 of file G4MuPairProductionModel.hh.

Referenced by Initialise(), MakeSamplingTables(), RetrieveTables(), G4MuonToMuonPairProductionModel::SampleSecondaries(), SampleSecondaries(), and StoreTables().

◆ particle

const G4ParticleDefinition* G4MuPairProductionModel::particle = nullptr

protected

Definition at line 144 of file G4MuPairProductionModel.hh.

Referenced by Initialise(), InitialiseLocal(), RetrieveTables(), G4MuonToMuonPairProductionModel::SampleSecondaries(), SampleSecondaries(), SetParticle(), and StoreTables().

◆ particleMass

G4double G4MuPairProductionModel::particleMass = 0.0

protected

Definition at line 149 of file G4MuPairProductionModel.hh.

Referenced by G4MuonToMuonPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), MaxSecondaryEnergyForElement(), SampleSecondaries(), and SetParticle().

◆ sqrte

G4double G4MuPairProductionModel::sqrte

protected

Definition at line 148 of file G4MuPairProductionModel.hh.

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

◆ wgi

const G4double G4MuPairProductionModel::wgi

staticprotected

Initial value:

= {
    0.0506142681451880, 0.1111905172266870, 0.1568533229389435, 0.1813418916891810,
    0.1813418916891810, 0.1568533229389435, 0.1111905172266870, 0.0506142681451880
  }

Definition at line 103 of file G4MuPairProductionModel.hh.

Referenced by G4MuonToMuonPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), ComputeMicroscopicCrossSection(), and ComputMuPairLoss().

◆ xgi

const G4double G4MuPairProductionModel::xgi

staticprotected

Initial value:

= {
    0.0198550717512320, 0.1016667612931865, 0.2372337950418355, 0.4082826787521750,
    0.5917173212478250, 0.7627662049581645, 0.8983332387068135, 0.9801449282487680
  }

Definition at line 98 of file G4MuPairProductionModel.hh.

Referenced by G4MuonToMuonPairProductionModel::ComputeDMicroscopicCrossSection(), ComputeDMicroscopicCrossSection(), ComputeMicroscopicCrossSection(), and ComputMuPairLoss().

◆ ymin

G4double G4MuPairProductionModel::ymin = -5.0

protected

Definition at line 159 of file G4MuPairProductionModel.hh.

Referenced by Initialise(), MakeSamplingTables(), G4MuonToMuonPairProductionModel::SampleSecondaries(), and SampleSecondaries().

◆ z13

G4double G4MuPairProductionModel::z13 = 0.0

protected

Definition at line 150 of file G4MuPairProductionModel.hh.

Referenced by ComputeDMicroscopicCrossSection(), and MaxSecondaryEnergyForElement().

◆ z23

G4double G4MuPairProductionModel::z23 = 0.0

protected

Definition at line 151 of file G4MuPairProductionModel.hh.

Referenced by ComputeDMicroscopicCrossSection(), and MaxSecondaryEnergyForElement().

◆ ZDATPAIR

const G4int G4MuPairProductionModel::ZDATPAIR = {1, 4, 13, 29, 92}

staticprotected

Definition at line 96 of file G4MuPairProductionModel.hh.

Referenced by FindScaledEnergy(), MakeSamplingTables(), RetrieveTables(), G4MuonToMuonPairProductionModel::SampleSecondaries(), SampleSecondaries(), and StoreTables().

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

◆ G4MuPairProductionModel() [1/2]

◆ ~G4MuPairProductionModel()

◆ G4MuPairProductionModel() [2/2]

Member Function Documentation

◆ ComputeCrossSectionPerAtom()

◆ ComputeDEDXPerVolume()

◆ ComputeDMicroscopicCrossSection()

◆ ComputeMicroscopicCrossSection()

◆ ComputMuPairLoss()

◆ DataCorrupted()

◆ FindScaledEnergy()

◆ Initialise()

◆ InitialiseLocal()

◆ MakeSamplingTables()

◆ MaxSecondaryEnergyForElement()

◆ MinPrimaryEnergy()

◆ operator=()

◆ RetrieveTables()

◆ SampleSecondaries()

◆ SetLowestKineticEnergy()

◆ SetParticle()

◆ StoreTables()

Member Data Documentation

◆ currentZ

◆ dy

◆ emax

◆ emin

◆ factorForCross

◆ fParticleChange

◆ fTableToFile

◆ lnZ

◆ lowestKinEnergy

◆ minPairEnergy

◆ nbine

◆ nbiny

◆ NINTPAIR

◆ nist

◆ nYBinPerDecade

◆ NZDATPAIR

◆ particle

◆ particleMass

◆ sqrte

◆ wgi

◆ xgi

◆ ymin

◆ z13

◆ z23

◆ ZDATPAIR