G4AnnihiToMuPair Class Reference

#include <G4AnnihiToMuPair.hh>

Inheritance diagram for G4AnnihiToMuPair:

Collaboration diagram for G4AnnihiToMuPair:

Public Member Functions
	G4AnnihiToMuPair (const G4String &processName="AnnihiToMuPair", G4ProcessType type=fElectromagnetic)
	~G4AnnihiToMuPair ()
G4bool	IsApplicable (const G4ParticleDefinition &)
void	BuildPhysicsTable (const G4ParticleDefinition &)
void	PrintInfoDefinition ()
void	SetCrossSecFactor (G4double fac)
G4double	GetCrossSecFactor ()
G4double	CrossSectionPerVolume (G4double PositronEnergy, const G4Material *)
G4double	ComputeCrossSectionPerAtom (G4double PositronEnergy, G4double AtomicZ)
G4double	GetMeanFreePath (const G4Track &aTrack, G4double previousStepSize, G4ForceCondition *)
G4VParticleChange *	PostStepDoIt (const G4Track &aTrack, const G4Step &aStep)
Public Member Functions inherited from G4VDiscreteProcess
	G4VDiscreteProcess (const G4String &, G4ProcessType aType=fNotDefined)
	G4VDiscreteProcess (G4VDiscreteProcess &)
virtual	~G4VDiscreteProcess ()
virtual G4double	PostStepGetPhysicalInteractionLength (const G4Track &track, G4double previousStepSize, G4ForceCondition *condition)
virtual G4double	AlongStepGetPhysicalInteractionLength (const G4Track &, G4double, G4double, G4double &, G4GPILSelection *)
virtual G4double	AtRestGetPhysicalInteractionLength (const G4Track &, G4ForceCondition *)
virtual G4VParticleChange *	AtRestDoIt (const G4Track &, const G4Step &)
virtual G4VParticleChange *	AlongStepDoIt (const G4Track &, const G4Step &)
Public Member Functions inherited from G4VProcess
	G4VProcess (const G4String &aName="NoName", G4ProcessType aType=fNotDefined)
	G4VProcess (const G4VProcess &right)
virtual	~G4VProcess ()
G4int	operator== (const G4VProcess &right) const
G4int	operator!= (const G4VProcess &right) const
G4double	GetCurrentInteractionLength () const
void	SetPILfactor (G4double value)
G4double	GetPILfactor () const
G4double	AlongStepGPIL (const G4Track &track, G4double previousStepSize, G4double currentMinimumStep, G4double &proposedSafety, G4GPILSelection *selection)
G4double	AtRestGPIL (const G4Track &track, G4ForceCondition *condition)
G4double	PostStepGPIL (const G4Track &track, G4double previousStepSize, G4ForceCondition *condition)
virtual void	PreparePhysicsTable (const G4ParticleDefinition &)
virtual G4bool	StorePhysicsTable (const G4ParticleDefinition *, const G4String &, G4bool)
virtual G4bool	RetrievePhysicsTable (const G4ParticleDefinition *, const G4String &, G4bool)
const G4String &	GetPhysicsTableFileName (const G4ParticleDefinition *, const G4String &directory, const G4String &tableName, G4bool ascii=false)
const G4String &	GetProcessName () const
G4ProcessType	GetProcessType () const
void	SetProcessType (G4ProcessType)
G4int	GetProcessSubType () const
void	SetProcessSubType (G4int)
virtual void	StartTracking (G4Track *)
virtual void	EndTracking ()
virtual void	SetProcessManager (const G4ProcessManager *)
virtual const G4ProcessManager *	GetProcessManager ()
virtual void	ResetNumberOfInteractionLengthLeft ()
G4double	GetNumberOfInteractionLengthLeft () const
G4double	GetTotalNumberOfInteractionLengthTraversed () const
G4bool	isAtRestDoItIsEnabled () const
G4bool	isAlongStepDoItIsEnabled () const
G4bool	isPostStepDoItIsEnabled () const
virtual void	DumpInfo () const
void	SetVerboseLevel (G4int value)
G4int	GetVerboseLevel () const
virtual void	SetMasterProcess (G4VProcess *masterP)
const G4VProcess *	GetMasterProcess () const
virtual void	BuildWorkerPhysicsTable (const G4ParticleDefinition &part)
virtual void	PrepareWorkerPhysicsTable (const G4ParticleDefinition &)

Private Member Functions
G4AnnihiToMuPair &	operator= (const G4AnnihiToMuPair &right)
	G4AnnihiToMuPair (const G4AnnihiToMuPair &)

Private Attributes
G4double	LowestEnergyLimit
G4double	HighestEnergyLimit
G4double	CurrentSigma
G4double	CrossSecFactor

Additional Inherited Members
Static Public Member Functions inherited from G4VProcess
static const G4String &	GetProcessTypeName (G4ProcessType)
Protected Member Functions inherited from G4VProcess
void	SubtractNumberOfInteractionLengthLeft (G4double previousStepSize)
void	ClearNumberOfInteractionLengthLeft ()
Protected Attributes inherited from G4VProcess
const G4ProcessManager *	aProcessManager
G4VParticleChange *	pParticleChange
G4ParticleChange	aParticleChange
G4double	theNumberOfInteractionLengthLeft
G4double	currentInteractionLength
G4double	theInitialNumberOfInteractionLength
G4String	theProcessName
G4String	thePhysicsTableFileName
G4ProcessType	theProcessType
G4int	theProcessSubType
G4double	thePILfactor
G4bool	enableAtRestDoIt
G4bool	enableAlongStepDoIt
G4bool	enablePostStepDoIt
G4int	verboseLevel

Detailed Description

Definition at line 57 of file G4AnnihiToMuPair.hh.

Constructor & Destructor Documentation

G4AnnihiToMuPair() [1/2]

G4AnnihiToMuPair::G4AnnihiToMuPair	(	const G4String &	processName = "AnnihiToMuPair",
		G4ProcessType	type = fElectromagnetic
	)

Definition at line 58 of file G4AnnihiToMuPair.cc.

                       :G4VDiscreteProcess (processName, type)
{
 //e+ Energy threshold
 const G4double Mu_massc2 = G4MuonPlus::MuonPlus()->GetPDGMass();
 LowestEnergyLimit  = 2*Mu_massc2*Mu_massc2/electron_mass_c2 - electron_mass_c2;
 
 //modele ok up to 1000 TeV due to neglected Z-interference
 HighestEnergyLimit = 1000*TeV;
 
 CurrentSigma = 0.0;
 CrossSecFactor = 1.;
 SetProcessSubType(6);

}

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~G4AnnihiToMuPair()

G4AnnihiToMuPair::~G4AnnihiToMuPair

(

)

Definition at line 76 of file G4AnnihiToMuPair.cc.

{ }

G4AnnihiToMuPair() [2/2]

G4AnnihiToMuPair::G4AnnihiToMuPair ( const G4AnnihiToMuPair &  )

private

Member Function Documentation

BuildPhysicsTable()

void G4AnnihiToMuPair::BuildPhysicsTable ( const G4ParticleDefinition &  )

virtual

Reimplemented from G4VProcess.

Definition at line 88 of file G4AnnihiToMuPair.cc.

{
  CurrentSigma = 0.0;
  PrintInfoDefinition();
}

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ComputeCrossSectionPerAtom()

G4double G4AnnihiToMuPair::ComputeCrossSectionPerAtom	(	G4double	PositronEnergy,
		G4double	AtomicZ
	)

Definition at line 108 of file G4AnnihiToMuPair.cc.

{
  static const G4double Mmuon = G4MuonPlus::MuonPlus()->GetPDGMass();
  static const G4double Rmuon = elm_coupling/Mmuon; //classical particle radius
  static const G4double Sig0  = pi*Rmuon*Rmuon/3.;  //constant in crossSection

  G4double CrossSection = 0.;
  if (Epos < LowestEnergyLimit) return CrossSection;
   
  G4double xi = LowestEnergyLimit/Epos;
  G4double SigmaEl = Sig0*xi*(1.+xi/2.)*sqrt(1.-xi); // per electron
  CrossSection = SigmaEl*Z;         // number of electrons per atom
  return CrossSection;
}

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CrossSectionPerVolume()

G4double G4AnnihiToMuPair::CrossSectionPerVolume	(	G4double	PositronEnergy,
		const G4Material *	aMaterial
	)

Definition at line 127 of file G4AnnihiToMuPair.cc.

{
  const G4ElementVector* theElementVector = aMaterial->GetElementVector();
  const G4double* NbOfAtomsPerVolume = aMaterial->GetVecNbOfAtomsPerVolume();

  G4double SIGMA = 0.0;

  for ( size_t i=0 ; i < aMaterial->GetNumberOfElements() ; ++i )
  {
    G4double AtomicZ = (*theElementVector)[i]->GetZ();
    SIGMA += NbOfAtomsPerVolume[i] *
      ComputeCrossSectionPerAtom(PositronEnergy,AtomicZ);
  }
  return SIGMA;
}

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GetCrossSecFactor()

G4double G4AnnihiToMuPair::GetCrossSecFactor ( )

inline

Definition at line 81 of file G4AnnihiToMuPair.hh.

{return CrossSecFactor;};

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GetMeanFreePath()

G4double G4AnnihiToMuPair::GetMeanFreePath ( const G4Track &  aTrack, G4double  previousStepSize, G4ForceCondition *    )

virtual

Implements G4VDiscreteProcess.

Definition at line 146 of file G4AnnihiToMuPair.cc.

{
  const G4DynamicParticle* aDynamicPositron = aTrack.GetDynamicParticle();
  G4double PositronEnergy = aDynamicPositron->GetKineticEnergy()
                                              +electron_mass_c2;
  G4Material* aMaterial = aTrack.GetMaterial();
  CurrentSigma = CrossSectionPerVolume(PositronEnergy, aMaterial);

  // increase the CrossSection by CrossSecFactor (default 1)
  G4double mfp = DBL_MAX;
  if(CurrentSigma > DBL_MIN) mfp = 1.0/(CurrentSigma*CrossSecFactor);

  return mfp;
}

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IsApplicable()

G4bool G4AnnihiToMuPair::IsApplicable ( const G4ParticleDefinition &  particle )

virtual

Reimplemented from G4VProcess.

Definition at line 81 of file G4AnnihiToMuPair.cc.

{
  return ( &particle == G4Positron::Positron() );
}

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operator=()

G4AnnihiToMuPair& G4AnnihiToMuPair::operator= ( const G4AnnihiToMuPair &  right )

private

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PostStepDoIt()

G4VParticleChange * G4AnnihiToMuPair::PostStepDoIt ( const G4Track &  aTrack, const G4Step &  aStep  )

virtual

Reimplemented from G4VDiscreteProcess.

Definition at line 167 of file G4AnnihiToMuPair.cc.

{

  aParticleChange.Initialize(aTrack);
  static const G4double Mele=electron_mass_c2;
  static const G4double Mmuon=G4MuonPlus::MuonPlus()->GetPDGMass();

  // current Positron energy and direction, return if energy too low
  const G4DynamicParticle *aDynamicPositron = aTrack.GetDynamicParticle();
  G4double Epos = aDynamicPositron->GetKineticEnergy() + Mele; 

  // test of cross section
  if(CurrentSigma*G4UniformRand() > 
     CrossSectionPerVolume(Epos, aTrack.GetMaterial())) 
    {
      return G4VDiscreteProcess::PostStepDoIt(aTrack,aStep);
    }

  if (Epos < LowestEnergyLimit) {
     return G4VDiscreteProcess::PostStepDoIt(aTrack,aStep);
  }

  G4ParticleMomentum PositronDirection = 
                                       aDynamicPositron->GetMomentumDirection();
  G4double xi = LowestEnergyLimit/Epos; // xi is always less than 1,
                                        // goes to 0 at high Epos

  // generate cost
  //
  G4double cost;
  do { cost = 2.*G4UniformRand()-1.; }
  // Loop checking, 07-Aug-2015, Vladimir Ivanchenko
  while (2.*G4UniformRand() > 1.+xi+cost*cost*(1.-xi) ); 
                                                       //1+cost**2 at high Epos
  G4double sint = sqrt(1.-cost*cost);

  // generate phi
  //
  G4double phi=2.*pi*G4UniformRand();

  G4double Ecm   = sqrt(0.5*Mele*(Epos+Mele));
  G4double Pcm   = sqrt(Ecm*Ecm-Mmuon*Mmuon);
  G4double beta  = sqrt((Epos-Mele)/(Epos+Mele));
  G4double gamma = Ecm/Mele;                    // =sqrt((Epos+Mele)/(2.*Mele));
  G4double Pt    = Pcm*sint;
  
  // energy and momentum of the muons in the Lab
  //
  G4double EmuPlus   = gamma*(     Ecm+cost*beta*Pcm);
  G4double EmuMinus  = gamma*(     Ecm-cost*beta*Pcm);
  G4double PmuPlusZ  = gamma*(beta*Ecm+cost*     Pcm);
  G4double PmuMinusZ = gamma*(beta*Ecm-cost*     Pcm);
  G4double PmuPlusX  = Pt*cos(phi);
  G4double PmuPlusY  = Pt*sin(phi);
  G4double PmuMinusX =-Pt*cos(phi);
  G4double PmuMinusY =-Pt*sin(phi);
  // absolute momenta
  G4double PmuPlus  = sqrt(Pt*Pt+PmuPlusZ *PmuPlusZ );
  G4double PmuMinus = sqrt(Pt*Pt+PmuMinusZ*PmuMinusZ);

  // mu+ mu- directions for Positron in z-direction
  //
  G4ThreeVector
    MuPlusDirection ( PmuPlusX/PmuPlus, PmuPlusY/PmuPlus,  PmuPlusZ/PmuPlus  );
  G4ThreeVector
    MuMinusDirection(PmuMinusX/PmuMinus,PmuMinusY/PmuMinus,PmuMinusZ/PmuMinus);

  // rotate to actual Positron direction
  //
  MuPlusDirection.rotateUz(PositronDirection);
  MuMinusDirection.rotateUz(PositronDirection);

  aParticleChange.SetNumberOfSecondaries(2);
  // create G4DynamicParticle object for the particle1
  G4DynamicParticle* aParticle1= new G4DynamicParticle(
                         G4MuonPlus::MuonPlus(),MuPlusDirection,EmuPlus-Mmuon);
  aParticleChange.AddSecondary(aParticle1);
  // create G4DynamicParticle object for the particle2
  G4DynamicParticle* aParticle2= new G4DynamicParticle(
                     G4MuonMinus::MuonMinus(),MuMinusDirection,EmuMinus-Mmuon);
  aParticleChange.AddSecondary(aParticle2);

  // Kill the incident positron 
  //
  aParticleChange.ProposeEnergy(0.); 
  aParticleChange.ProposeTrackStatus(fStopAndKill);

  return &aParticleChange;
}

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PrintInfoDefinition()

void G4AnnihiToMuPair::PrintInfoDefinition

(

)

Definition at line 263 of file G4AnnihiToMuPair.cc.

{
  G4String comments ="e+e->mu+mu- annihilation, atomic e- at rest, SubType=.";
  G4cout << G4endl << GetProcessName() << ":  " << comments 
     << GetProcessSubType() << G4endl;
  G4cout << "        threshold at " << LowestEnergyLimit/GeV << " GeV"
         << " good description up to "
         << HighestEnergyLimit/TeV << " TeV for all Z." << G4endl;
}

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SetCrossSecFactor()

void G4AnnihiToMuPair::SetCrossSecFactor

(

G4double

fac

)

Definition at line 98 of file G4AnnihiToMuPair.cc.

{ 
  CrossSecFactor = fac;
  G4cout << "The cross section for AnnihiToMuPair is artificially "
         << "increased by the CrossSecFactor=" << CrossSecFactor << G4endl;
}

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Member Data Documentation

CrossSecFactor

G4double G4AnnihiToMuPair::CrossSecFactor

private

Definition at line 119 of file G4AnnihiToMuPair.hh.

CurrentSigma

G4double G4AnnihiToMuPair::CurrentSigma

private

Definition at line 117 of file G4AnnihiToMuPair.hh.

HighestEnergyLimit

G4double G4AnnihiToMuPair::HighestEnergyLimit

private

Definition at line 115 of file G4AnnihiToMuPair.hh.

LowestEnergyLimit

G4double G4AnnihiToMuPair::LowestEnergyLimit

private

Definition at line 114 of file G4AnnihiToMuPair.hh.

---

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

• G4AnnihiToMuPair.hh
• G4AnnihiToMuPair.cc