G4GammaTransition Class Reference

#include <G4GammaTransition.hh>

Inheritance diagram for G4GammaTransition:

Collaboration diagram for G4GammaTransition:

Public Member Functions
	G4GammaTransition ()
virtual	~G4GammaTransition ()
virtual G4Fragment *	SampleTransition (G4Fragment *nucleus, G4double newExcEnergy, G4double mpRatio, G4int JP1, G4int JP2, G4int MP, G4int shell, G4bool isDiscrete, G4bool isGamma)
virtual void	SampleDirection (G4Fragment *nuc, G4double ratio, G4int twoJ1, G4int twoJ2, G4int mp)
void	SetPolarizationFlag (G4bool val)
void	SetVerbose (G4int val)

Protected Attributes
G4ThreeVector	fDirection
G4PolarizationTransition	fPolTrans
G4int	fVerbose

Detailed Description

Definition at line 53 of file G4GammaTransition.hh.

Constructor & Destructor Documentation

G4GammaTransition::G4GammaTransition ( )

explicit

Definition at line 49 of file G4GammaTransition.cc.

  : polarFlag(false), fDirection(0.,0.,0.), fVerbose(0)
{}

G4GammaTransition::~G4GammaTransition ( )

virtual

Definition at line 53 of file G4GammaTransition.cc.

{}

Member Function Documentation

void G4GammaTransition::SampleDirection ( G4Fragment *  nuc, G4double  ratio, G4int  twoJ1, G4int  twoJ2, G4int  mp  )

virtual

Reimplemented in G4PolarizedGammaTransition.

Definition at line 154 of file G4GammaTransition.cc.

{
  // PhotonEvaporation dataset:
  // The multipolarity number with 1,2,3,4,5,6,7 representing E0,E1,M1,E2,M2,E3,M3
  // monopole transition and 100*Nx+Ny representing multipolarity transition with
  // Ny and Ny taking the value 1,2,3,4,5,6,7 referring to E0,E1,M1,E2,M2,E3,M3,..
  // For example a M1+E2 transition would be written 304.
  // M1 is the primary transition (L) and E2 is the secondary (L')

  G4double mpRatio = ratio;

  G4int L0 = 0, Lp = 0;
  if (mp > 99) {
    L0 = mp/200;
    Lp = (mp%100)/2;
  } else {
    L0 = mp/2;
    Lp = 0;
    mpRatio = 0.;
  } 

  fPolTrans.SetGammaTransitionData(twoJ1, twoJ2, L0, mpRatio, Lp);
  G4NuclearPolarization* np = nuc->GetNuclearPolarization();

  G4double cosTheta, phi;
  if(!np) {
    // initial state is non-polarized - create polarization
    np = new G4NuclearPolarization();
    nuc->SetNuclearPolarization(np);
    cosTheta = 2*G4UniformRand() - 1.0;
    phi = CLHEP::twopi*G4UniformRand();

  } else {

    // initial state is polarized - generate correlation
    cosTheta = fPolTrans.GenerateGammaCosTheta(np->GetPolarization());
    phi = fPolTrans.GenerateGammaPhi(cosTheta, np->GetPolarization());
  }
  fPolTrans.UpdatePolarizationToFinalState(cosTheta, phi, nuc);

  G4double sinTheta = std::sqrt((1.-cosTheta)*(1.+cosTheta));
  fDirection.set(sinTheta*std::cos(phi),sinTheta*std::sin(phi),cosTheta);
  if(fVerbose > 1) {
    G4cout << "G4GammaTransition::SampleDirection : " << fDirection << G4endl;
    G4cout << "Polarisation : " << *np << G4endl;
  }
}

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G4Fragment * G4GammaTransition::SampleTransition ( G4Fragment *  nucleus, G4double  newExcEnergy, G4double  mpRatio, G4int  JP1, G4int  JP2, G4int  MP, G4int  shell, G4bool  isDiscrete, G4bool  isGamma  )

virtual

Definition at line 57 of file G4GammaTransition.cc.

{
  G4Fragment* result = nullptr;
  G4double bond_energy = 0.0;

  if (!isGamma) { 
    if(0 <= shell) {
      G4int Z = nucleus->GetZ_asInt();
      if(Z <= 100) {
    G4int idx = (G4int)shell;
    idx = std::min(idx, G4AtomicShells::GetNumberOfShells(Z)-1);
    bond_energy = G4AtomicShells::GetBindingEnergy(Z, idx);
      }
    }
  }
  G4double etrans = nucleus->GetExcitationEnergy() - newExcEnergy 
    - bond_energy;
  if(fVerbose > 1) {
    G4cout << "G4GammaTransition::GenerateGamma - Etrans(MeV)= " 
       << etrans << "  Eexnew= " << newExcEnergy 
       << " Ebond= " << bond_energy << G4endl;
  } 
  if(etrans <= 0.0) { 
    etrans += bond_energy;
    bond_energy = 0.0;
  }
  
  // Do complete Lorentz computation 
  G4LorentzVector lv = nucleus->GetMomentum();
  G4double mass = nucleus->GetGroundStateMass() + newExcEnergy;
  //G4double e0 = lv.e();

  // select secondary
  G4ParticleDefinition* part;

  if(isGamma) { part =  G4Gamma::Gamma(); }
  else {
    part = G4Electron::Electron();
    G4int ne = std::max(nucleus->GetNumberOfElectrons() - 1, 0);
    nucleus->SetNumberOfElectrons(ne);
  }

  if(polarFlag && isDiscrete) {
    SampleDirection(nucleus, mpRatio, JP1, JP2, MP);
  } else {
    fDirection = G4RandomDirection();
  }

  G4double emass = part->GetPDGMass();

  // 2-body decay in rest frame
  G4double ecm       = lv.mag();
  G4ThreeVector bst  = lv.boostVector();
  if(!isGamma) { ecm += (CLHEP::electron_mass_c2 - bond_energy); }

  //G4cout << "Ecm= " << ecm << " mass= " << mass << " emass= " << emass << G4endl;

  ecm = std::max(ecm, mass + emass);
  G4double energy = 0.5*((ecm - mass)*(ecm + mass) + emass*emass)/ecm;
  G4double mom = (emass > 0.0) ? std::sqrt((energy - emass)*(energy + emass))
    : energy;

  // emitted gamma or e-
  G4LorentzVector res4mom(mom * fDirection.x(),
              mom * fDirection.y(),
              mom * fDirection.z(), energy);
  // residual
  energy = std::max(ecm - energy, mass);
  lv.set(-mom*fDirection.x(), -mom*fDirection.y(), -mom*fDirection.z(), energy);

  // Lab system transform for short lived level
  lv.boost(bst);

  // modified primary fragment 
  nucleus->SetExcEnergyAndMomentum(newExcEnergy, lv);

  // gamma or e- are produced
  res4mom.boost(bst); 
  result = new G4Fragment(res4mom, part);

  //G4cout << " DeltaE= " << e0 - lv.e() - res4mom.e() + emass
  //     << "   Emass= " << emass << G4endl;
  if(fVerbose > 1) {
    G4cout << "G4GammaTransition::SampleTransition : " << result << G4endl;
    G4cout << "       Left nucleus: " << nucleus << G4endl;
  }
  return result;
}

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void G4GammaTransition::SetPolarizationFlag ( G4bool  val )

inline

Definition at line 74 of file G4GammaTransition.hh.

{ polarFlag = val; };

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void G4GammaTransition::SetVerbose ( G4int  val )

inline

Definition at line 76 of file G4GammaTransition.hh.

{ fVerbose = val; fPolTrans.SetVerbose(val); };

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Member Data Documentation

G4ThreeVector G4GammaTransition::fDirection

protected

Definition at line 89 of file G4GammaTransition.hh.

G4PolarizationTransition G4GammaTransition::fPolTrans

protected

Definition at line 90 of file G4GammaTransition.hh.

G4int G4GammaTransition::fVerbose

protected

Definition at line 91 of file G4GammaTransition.hh.

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

• geant4.10.03.p01/source/processes/hadronic/models/de_excitation/photon_evaporation/include/G4GammaTransition.hh
• geant4.10.03.p01/source/processes/hadronic/models/de_excitation/photon_evaporation/src/G4GammaTransition.cc