G4ChargeExchange Class Reference

#include <G4ChargeExchange.hh>

Inheritance diagram for G4ChargeExchange:

Collaboration diagram for G4ChargeExchange:

Public Member Functions
	G4ChargeExchange ()
virtual	~G4ChargeExchange ()
virtual G4HadFinalState *	ApplyYourself (const G4HadProjectile &aTrack, G4Nucleus &targetNucleus)
void	SetLowestEnergyLimit (G4double value)
void	SetRecoilKinEnergyLimit (G4double value)
G4double	SampleT (G4double p, G4double A)
Public Member Functions inherited from G4HadronicInteraction
	G4HadronicInteraction (const G4String &modelName="HadronicModel")
virtual	~G4HadronicInteraction ()
virtual G4double	SampleInvariantT (const G4ParticleDefinition *p, G4double plab, G4int Z, G4int A)
virtual G4bool	IsApplicable (const G4HadProjectile &aTrack, G4Nucleus &targetNucleus)
G4double	GetMinEnergy () const
G4double	GetMinEnergy (const G4Material *aMaterial, const G4Element *anElement) const
void	SetMinEnergy (G4double anEnergy)
void	SetMinEnergy (G4double anEnergy, const G4Element *anElement)
void	SetMinEnergy (G4double anEnergy, const G4Material *aMaterial)
G4double	GetMaxEnergy () const
G4double	GetMaxEnergy (const G4Material *aMaterial, const G4Element *anElement) const
void	SetMaxEnergy (const G4double anEnergy)
void	SetMaxEnergy (G4double anEnergy, const G4Element *anElement)
void	SetMaxEnergy (G4double anEnergy, const G4Material *aMaterial)
G4int	GetVerboseLevel () const
void	SetVerboseLevel (G4int value)
const G4String &	GetModelName () const
void	DeActivateFor (const G4Material *aMaterial)
void	ActivateFor (const G4Material *aMaterial)
void	DeActivateFor (const G4Element *anElement)
void	ActivateFor (const G4Element *anElement)
G4bool	IsBlocked (const G4Material *aMaterial) const
G4bool	IsBlocked (const G4Element *anElement) const
void	SetRecoilEnergyThreshold (G4double val)
G4double	GetRecoilEnergyThreshold () const
virtual const std::pair < G4double, G4double >	GetFatalEnergyCheckLevels () const
virtual std::pair< G4double, G4double >	GetEnergyMomentumCheckLevels () const
void	SetEnergyMomentumCheckLevels (G4double relativeLevel, G4double absoluteLevel)
virtual void	ModelDescription (std::ostream &outFile) const
virtual void	BuildPhysicsTable (const G4ParticleDefinition &)
virtual void	InitialiseModel ()

Additional Inherited Members
Protected Member Functions inherited from G4HadronicInteraction
void	SetModelName (const G4String &nam)
G4bool	IsBlocked () const
void	Block ()
Protected Attributes inherited from G4HadronicInteraction
G4HadFinalState	theParticleChange
G4int	verboseLevel
G4double	theMinEnergy
G4double	theMaxEnergy
G4bool	isBlocked

Detailed Description

Definition at line 52 of file G4ChargeExchange.hh.

Constructor & Destructor Documentation

G4ChargeExchange::G4ChargeExchange

(

)

Definition at line 54 of file G4ChargeExchange.cc.

                                   : G4HadronicInteraction("Charge Exchange")
{
  SetMinEnergy( 0.0*GeV );
  SetMaxEnergy( 100.*TeV );

  lowEnergyRecoilLimit = 100.*keV;  
  lowestEnergyLimit    = 1.*MeV;  

  theProton   = G4Proton::Proton();
  theNeutron  = G4Neutron::Neutron();
  theAProton  = G4AntiProton::AntiProton();
  theANeutron = G4AntiNeutron::AntiNeutron();
  thePiPlus   = G4PionPlus::PionPlus();
  thePiMinus  = G4PionMinus::PionMinus();
  thePiZero   = G4PionZero::PionZero();
  theKPlus    = G4KaonPlus::KaonPlus();
  theKMinus   = G4KaonMinus::KaonMinus();
  theK0S      = G4KaonZeroShort::KaonZeroShort();
  theK0L      = G4KaonZeroLong::KaonZeroLong();
  theL        = G4Lambda::Lambda();
  theAntiL    = G4AntiLambda::AntiLambda();
  theSPlus    = G4SigmaPlus::SigmaPlus();
  theASPlus   = G4AntiSigmaPlus::AntiSigmaPlus();
  theSMinus   = G4SigmaMinus::SigmaMinus();
  theASMinus  = G4AntiSigmaMinus::AntiSigmaMinus();
  theS0       = G4SigmaZero::SigmaZero();
  theAS0      = G4AntiSigmaZero::AntiSigmaZero();
  theXiMinus  = G4XiMinus::XiMinus();
  theXi0      = G4XiZero::XiZero();
  theAXiMinus = G4AntiXiMinus::AntiXiMinus();
  theAXi0     = G4AntiXiZero::AntiXiZero();
  theOmega    = G4OmegaMinus::OmegaMinus();
  theAOmega   = G4AntiOmegaMinus::AntiOmegaMinus();
  theD        = G4Deuteron::Deuteron();
  theT        = G4Triton::Triton();
  theA        = G4Alpha::Alpha();
  theHe3      = G4He3::He3();
}

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G4ChargeExchange::~G4ChargeExchange ( )

virtual

Definition at line 93 of file G4ChargeExchange.cc.

{}

Member Function Documentation

G4HadFinalState * G4ChargeExchange::ApplyYourself ( const G4HadProjectile &  aTrack, G4Nucleus &  targetNucleus  )

virtual

Implements G4HadronicInteraction.

Definition at line 96 of file G4ChargeExchange.cc.

{
  theParticleChange.Clear();
  const G4HadProjectile* aParticle = &aTrack;
  G4double ekin = aParticle->GetKineticEnergy();

  G4int A = targetNucleus.GetA_asInt();
  G4int Z = targetNucleus.GetZ_asInt();

  if(ekin <= lowestEnergyLimit || A < 3) {
    theParticleChange.SetEnergyChange(ekin);
    theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
    return &theParticleChange;
  }

  G4double plab = aParticle->GetTotalMomentum();

  if (verboseLevel > 1)
    G4cout << "G4ChargeExchange::DoIt: Incident particle plab="
       << plab/GeV << " GeV/c "
       << " ekin(MeV) = " << ekin/MeV << "  "
       << aParticle->GetDefinition()->GetParticleName() << G4endl;

  // Scattered particle referred to axis of incident particle
  const G4ParticleDefinition* theParticle = aParticle->GetDefinition();

  G4int N = A - Z;
  G4int projPDG = theParticle->GetPDGEncoding();
  if (verboseLevel > 1)
    G4cout << "G4ChargeExchange for " << theParticle->GetParticleName()
       << " PDGcode= " << projPDG << " on nucleus Z= " << Z
       << " A= " << A << " N= " << N
       << G4endl;

  G4ParticleDefinition * theDef = 0;

  G4double mass2 = G4NucleiProperties::GetNuclearMass((G4double)A, (G4double)Z);
  G4LorentzVector lv1 = aParticle->Get4Momentum();
  G4LorentzVector lv0(0.0,0.0,0.0,mass2);

  G4LorentzVector lv  = lv0 + lv1;
  G4ThreeVector bst = lv.boostVector();
  lv1.boost(-bst);
  lv0.boost(-bst);

  // Sample final particles
  G4bool theHyperon = false;
  G4ParticleDefinition* theRecoil = 0;
  G4ParticleDefinition* theSecondary = 0;

  if(theParticle == theProton) {
    theSecondary = theNeutron;
    Z++;
  } else if(theParticle == theNeutron) {
    theSecondary = theProton;
    Z--;
  } else if(theParticle == thePiPlus) {
    theSecondary = thePiZero;
    Z++;
  } else if(theParticle == thePiMinus) {
    theSecondary = thePiZero;
    Z--;
  } else if(theParticle == theKPlus) {
    if(G4UniformRand()<0.5) theSecondary = theK0S;
    else  theSecondary = theK0L;
    Z++;
  } else if(theParticle == theKMinus) {
    if(G4UniformRand()<0.5) theSecondary = theK0S;
    else  theSecondary = theK0L;
    Z--;
  } else if(theParticle == theK0S || theParticle == theK0L) {
    if(G4UniformRand()*A < G4double(Z)) {
      theSecondary = theKPlus;
      Z--;
    } else {
      theSecondary = theKMinus;
      Z++;
    }
  } else if(theParticle == theANeutron) {
    theSecondary = theAProton;
    Z++;
  } else if(theParticle == theAProton) {
    theSecondary = theANeutron;
    Z--;
  } else if(theParticle == theL) {
    G4double x = G4UniformRand();
    if(G4UniformRand()*A < G4double(Z)) {
      if(x < 0.2) {
        theSecondary = theS0;
      } else if (x < 0.4) {
        theSecondary = theSPlus;
        Z--;
      } else if (x < 0.6) {
        theSecondary = theProton;
    theRecoil = theL;
        theHyperon = true;
    A--;
      } else if (x < 0.8) {
        theSecondary = theProton;
    theRecoil = theS0;
        theHyperon = true;
        A--;
      } else {
        theSecondary = theNeutron;
    theRecoil = theSPlus;
        theHyperon = true;
        A--;
      }
    } else {
      if(x < 0.2) {
        theSecondary = theS0;
      } else if (x < 0.4) {
        theSecondary = theSMinus;
        Z++;
      } else if (x < 0.6) {
        theSecondary = theNeutron;
    theRecoil = theL;
        A--;
        theHyperon = true;
      } else if (x < 0.8) {
        theSecondary = theNeutron;
    theRecoil = theS0;
        theHyperon = true;
        A--;
      } else {
        theSecondary = theProton;
    theRecoil = theSMinus;
        theHyperon = true;
        A--;
      }
    }
  }

  if (Z == 1 && A == 2) theDef = theD;
  else if (Z == 1 && A == 3) theDef = theT;
  else if (Z == 2 && A == 3) theDef = theHe3;
  else if (Z == 2 && A == 4) theDef = theA;
  else {
    theDef = 
      G4ParticleTable::GetParticleTable()->GetIonTable()->GetIon(Z,A,0.0);
  }
  if(!theSecondary) { return &theParticleChange; }

  G4double m11 = theSecondary->GetPDGMass();
  G4double m21 = theDef->GetPDGMass();
  if(theRecoil)  { m21 += theRecoil->GetPDGMass(); }
  else           { theRecoil = theDef; }

  G4double etot = lv0.e() + lv1.e();

  // kinematiacally impossible
  if(etot < m11 + m21) {
    theParticleChange.SetEnergyChange(ekin);
    theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
    return &theParticleChange;
  }

  G4ThreeVector p1 = lv1.vect();
  G4double e1 = 0.5*etot*(1.0 - (m21*m21 - m11*m11)/(etot*etot));
  //  G4double e2 = etot - e1;
  G4double ptot = std::sqrt(e1*e1 - m11*m11);

  G4double tmax = 4.0*ptot*ptot;
  G4double g2 = GeV*GeV; 

  G4double t = g2*SampleT(tmax/g2, A);

  if(verboseLevel>1)
    G4cout <<"## G4ChargeExchange t= " << t << " tmax= " << tmax
       << " ptot= " << ptot << G4endl;

  // Sampling in CM system
  G4double phi  = G4UniformRand()*twopi;
  G4double cost = 1. - 2.0*t/tmax;
  if(std::abs(cost) > 1.0) cost = 1.0;
  G4double sint = std::sqrt((1.0-cost)*(1.0+cost));

  //if (verboseLevel > 1)
  //  G4cout << "cos(t)=" << cost << " std::sin(t)=" << sint << G4endl;

  G4ThreeVector v1(sint*std::cos(phi),sint*std::sin(phi),cost);
  v1 *= ptot;
  G4LorentzVector nlv1(v1.x(),v1.y(),v1.z(),e1);
  G4LorentzVector nlv0 = lv0 + lv1 - nlv1;

  nlv0.boost(bst);
  nlv1.boost(bst);

  theParticleChange.SetStatusChange(stopAndKill);
  theParticleChange.SetEnergyChange(0.0);
  G4DynamicParticle * aSec = new G4DynamicParticle(theSecondary, nlv1);
  theParticleChange.AddSecondary(aSec);

  G4double erec =  nlv0.e() - m21;

  //G4cout << "erec= " <<erec << " Esec= " << aSec->GetKineticEnergy() << G4endl;  

  if(theHyperon) {
    theParticleChange.SetLocalEnergyDeposit(erec);
    aSec = new G4DynamicParticle();
    aSec->SetDefinition(theRecoil);
    aSec->SetKineticEnergy(0.0);
  } else if(erec > lowEnergyRecoilLimit) {
    aSec = new G4DynamicParticle(theRecoil, nlv0);
    theParticleChange.AddSecondary(aSec);
  } else {
    if(erec < 0.0) erec = 0.0;
    theParticleChange.SetLocalEnergyDeposit(erec);
  }
  return &theParticleChange;
}

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G4double G4ChargeExchange::SampleT	(	G4double	p,
		G4double	A
	)

Definition at line 309 of file G4ChargeExchange.cc.

{
  G4double aa, bb, cc, dd;
  if (A <= 62.) {
    aa = G4Pow::GetInstance()->powA(A, 1.63);
    bb = 14.5*G4Pow::GetInstance()->powA(A, 0.66);
    cc = 1.4*G4Pow::GetInstance()->powA(A, 0.33);
    dd = 10.;
  } else {
    aa = G4Pow::GetInstance()->powA(A, 1.33);
    bb = 60.*G4Pow::GetInstance()->powA(A, 0.33);
    cc = 0.4*G4Pow::GetInstance()->powA(A, 0.40);
    dd = 10.;
  }
  G4double x1 = (1.0 - G4Exp(-tmax*bb))*aa/bb;
  G4double x2 = (1.0 - G4Exp(-tmax*dd))*cc/dd;
  
  G4double t;
  G4double y = bb;
  if(G4UniformRand()*(x1 + x2) < x2) y = dd;

  const G4int maxNumberOfLoops = 10000;
  G4int loopCounter = 0;
  do {
    t = -G4Log(G4UniformRand())/y;
  } while ( (t > tmax) &&
            ++loopCounter < maxNumberOfLoops );  /* Loop checking, 10.08.2015, A.Ribon */
  if ( loopCounter >= maxNumberOfLoops ) {
    t = 0.0;
  }

  return t;
}

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void G4ChargeExchange::SetLowestEnergyLimit ( G4double  value )

inline

Definition at line 112 of file G4ChargeExchange.hh.

{
  lowestEnergyLimit = value;
}

void G4ChargeExchange::SetRecoilKinEnergyLimit ( G4double  value )

inline

Definition at line 107 of file G4ChargeExchange.hh.

{
  lowEnergyRecoilLimit = value;
}

---

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

• geant4.10.03.p01/source/processes/hadronic/models/coherent_elastic/include/G4ChargeExchange.hh
• geant4.10.03.p01/source/processes/hadronic/models/coherent_elastic/src/G4ChargeExchange.cc