G4eBremsstrahlungRelModel Class Reference

#include <G4eBremsstrahlungRelModel.hh>

Inheritance diagram for G4eBremsstrahlungRelModel:

G4VEmModel G4SeltzerBergerModel

Public Member Functions

 G4eBremsstrahlungRelModel (const G4ParticleDefinition *p=0, const G4String &nam="eBremLPM")
virtual ~G4eBremsstrahlungRelModel ()
virtual void Initialise (const G4ParticleDefinition *, const G4DataVector &)
virtual G4double ComputeDEDXPerVolume (const G4Material *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy)
virtual G4double ComputeCrossSectionPerAtom (const G4ParticleDefinition *, G4double tkin, G4double Z, G4double, G4double cutEnergy, G4double maxEnergy=DBL_MAX)
virtual void SampleSecondaries (std::vector< G4DynamicParticle * > *, const G4MaterialCutsCouple *, const G4DynamicParticle *, G4double cutEnergy, G4double maxEnergy)
virtual void SetupForMaterial (const G4ParticleDefinition *, const G4Material *, G4double)
void SetLPMconstant (G4double val)
G4double LPMconstant () const

Protected Member Functions

virtual G4double ComputeDXSectionPerAtom (G4double gammaEnergy)
void SetCurrentElement (const G4double)

Protected Attributes

G4NistManager * nist
const G4ParticleDefinition * particle
G4ParticleDefinition * theGamma
G4ParticleChangeForLoss * fParticleChange
G4double bremFactor
G4double particleMass
G4double kinEnergy
G4double totalEnergy
G4double currentZ
G4double densityFactor
G4double densityCorr
G4bool isElectron

Detailed Description

Definition at line 60 of file G4eBremsstrahlungRelModel.hh.

Constructor & Destructor Documentation

G4eBremsstrahlungRelModel::G4eBremsstrahlungRelModel ( const G4ParticleDefinition *  p = 0,
const G4String &  nam = "eBremLPM" 
)

Definition at line 83 of file G4eBremsstrahlungRelModel.cc.

References currentZ, densityCorr, densityFactor, fParticleChange, G4Gamma::Gamma(), G4NistManager::Instance(), kinEnergy, nist, particleMass, G4VEmModel::SetAngularDistribution(), G4VEmModel::SetLowEnergyLimit(), G4VEmModel::SetLPMFlag(), theGamma, and totalEnergy.

00085   : G4VEmModel(nam),
00086     particle(0),
00087     bremFactor(fine_structure_const*classic_electr_radius*classic_electr_radius*16./3.),
00088     isElectron(true),
00089     fMigdalConstant(classic_electr_radius*electron_Compton_length*electron_Compton_length*4.0*pi),
00090     fLPMconstant(fine_structure_const*electron_mass_c2*electron_mass_c2/(4.*pi*hbarc)*0.5),
00091     fXiLPM(0), fPhiLPM(0), fGLPM(0),
00092     use_completescreening(false),isInitialised(false)
00093 {
00094   fParticleChange = 0;
00095   theGamma = G4Gamma::Gamma();
00096 
00097   lowKinEnergy = 0.1*GeV;
00098   SetLowEnergyLimit(lowKinEnergy);  
00099 
00100   nist = G4NistManager::Instance();  
00101 
00102   SetLPMFlag(true);
00103   //SetAngularDistribution(new G4ModifiedTsai());
00104   SetAngularDistribution(new G4DipBustGenerator());
00105 
00106   particleMass = kinEnergy = totalEnergy = currentZ = z13 = z23 = lnZ = Fel 
00107     = Finel = fCoulomb = fMax = densityFactor = densityCorr = lpmEnergy 
00108     = xiLPM = phiLPM = gLPM = klpm = kp = 0.0;
00109 
00110   energyThresholdLPM = 1.e39;
00111 
00112   InitialiseConstants();
00113   if(p) { SetParticle(p); }
00114 }

G4eBremsstrahlungRelModel::~G4eBremsstrahlungRelModel (  )  [virtual]

Definition at line 129 of file G4eBremsstrahlungRelModel.cc.

00130 {
00131 }

Member Function Documentation

G4double G4eBremsstrahlungRelModel::ComputeCrossSectionPerAtom ( const G4ParticleDefinition *  ,
G4double  tkin,
G4double  Z,
G4double  ,
G4double  cutEnergy,
G4double  maxEnergy = DBL_MAX 
) [virtual]

Reimplemented from G4VEmModel.

Definition at line 260 of file G4eBremsstrahlungRelModel.cc.

References bremFactor, kinEnergy, particle, and SetCurrentElement().

00266 {
00267   if(!particle) { SetParticle(p); }
00268   if(kineticEnergy < lowKinEnergy) { return 0.0; }
00269   G4double cut  = std::min(cutEnergy, kineticEnergy);
00270   G4double tmax = std::min(maxEnergy, kineticEnergy);
00271 
00272   if(cut >= tmax) { return 0.0; }
00273 
00274   SetCurrentElement(Z);
00275 
00276   G4double cross = ComputeXSectionPerAtom(cut);
00277 
00278   // allow partial integration
00279   if(tmax < kinEnergy) { cross -= ComputeXSectionPerAtom(tmax); }
00280   
00281   cross *= Z*Z*bremFactor;
00282 
00283   return cross;
00284 }

G4double G4eBremsstrahlungRelModel::ComputeDEDXPerVolume ( const G4Material *  ,
const G4ParticleDefinition *  ,
G4double  kineticEnergy,
G4double  cutEnergy 
) [virtual]

Reimplemented from G4VEmModel.

Definition at line 190 of file G4eBremsstrahlungRelModel.cc.

References bremFactor, currentZ, G4Material::GetAtomicNumDensityVector(), G4Material::GetElementVector(), G4Material::GetNumberOfElements(), particle, SetCurrentElement(), G4VEmModel::SetCurrentElement(), and SetupForMaterial().

00195 {
00196   if(!particle) { SetParticle(p); }
00197   if(kineticEnergy < lowKinEnergy) { return 0.0; }
00198   G4double cut = std::min(cutEnergy, kineticEnergy);
00199   if(cut == 0.0) { return 0.0; }
00200 
00201   SetupForMaterial(particle, material,kineticEnergy);
00202 
00203   const G4ElementVector* theElementVector = material->GetElementVector();
00204   const G4double* theAtomicNumDensityVector = material->GetAtomicNumDensityVector();
00205 
00206   G4double dedx = 0.0;
00207 
00208   //  loop for elements in the material
00209   for (size_t i=0; i<material->GetNumberOfElements(); i++) {
00210 
00211     G4VEmModel::SetCurrentElement((*theElementVector)[i]);
00212     SetCurrentElement((*theElementVector)[i]->GetZ());
00213 
00214     dedx += theAtomicNumDensityVector[i]*currentZ*currentZ*ComputeBremLoss(cut);
00215   }
00216   dedx *= bremFactor;
00217 
00218 
00219   return dedx;
00220 }

G4double G4eBremsstrahlungRelModel::ComputeDXSectionPerAtom ( G4double  gammaEnergy  )  [protected, virtual]

Reimplemented in G4SeltzerBergerModel.

Definition at line 428 of file G4eBremsstrahlungRelModel.cc.

References currentZ, and totalEnergy.

Referenced by SampleSecondaries().

00433 {
00434 
00435   if(gammaEnergy < 0.0) { return 0.0; }
00436 
00437   G4double y = gammaEnergy/totalEnergy;
00438 
00439   G4double main=0.,secondTerm=0.;
00440 
00441   if (use_completescreening|| currentZ<5) {
00442     // ** form factors complete screening case **      
00443     main   = (3./4.*y*y - y + 1.) * ( (Fel-fCoulomb) + Finel/currentZ );
00444     secondTerm = (1.-y)/12.*(1.+1./currentZ);
00445   }
00446   else {
00447     // ** intermediate screening using Thomas-Fermi FF from Tsai only valid for Z>=5** 
00448     G4double dd=100.*electron_mass_c2*y/(totalEnergy-gammaEnergy);
00449     G4double gg=dd/z13;
00450     G4double eps=dd/z23;
00451     G4double phi1=Phi1(gg,currentZ),  phi1m2=Phi1M2(gg,currentZ);
00452     G4double psi1=Psi1(eps,currentZ),  psi1m2=Psi1M2(eps,currentZ);
00453     
00454     main   = (3./4.*y*y - y + 1.) * ( (0.25*phi1-1./3.*lnZ-fCoulomb) + (0.25*psi1-2./3.*lnZ)/currentZ );
00455     secondTerm = (1.-y)/8.*(phi1m2+psi1m2/currentZ);
00456   }
00457   G4double cross = main+secondTerm;
00458   return cross;
00459 }

void G4eBremsstrahlungRelModel::Initialise ( const G4ParticleDefinition *  ,
const G4DataVector &   
) [virtual]

Implements G4VEmModel.

Reimplemented in G4SeltzerBergerModel.

Definition at line 172 of file G4eBremsstrahlungRelModel.cc.

References currentZ, fParticleChange, G4VEmModel::GetParticleChangeForLoss(), G4VEmModel::InitialiseElementSelectors(), and G4VEmModel::LowEnergyLimit().

Referenced by G4SeltzerBergerModel::Initialise().

00174 {
00175   if(p) { SetParticle(p); }
00176 
00177   lowKinEnergy  = LowEnergyLimit();
00178 
00179   currentZ = 0.;
00180 
00181   InitialiseElementSelectors(p, cuts);
00182 
00183   if(isInitialised) { return; }
00184   fParticleChange = GetParticleChangeForLoss();
00185   isInitialised = true;
00186 }

G4double G4eBremsstrahlungRelModel::LPMconstant (  )  const [inline]

Definition at line 250 of file G4eBremsstrahlungRelModel.hh.

00251 {
00252   return fLPMconstant;
00253 }

void G4eBremsstrahlungRelModel::SampleSecondaries ( std::vector< G4DynamicParticle * > *  ,
const G4MaterialCutsCouple *  ,
const G4DynamicParticle *  ,
G4double  cutEnergy,
G4double  maxEnergy 
) [virtual]

Implements G4VEmModel.

Reimplemented in G4SeltzerBergerModel.

Definition at line 463 of file G4eBremsstrahlungRelModel.cc.

References ComputeDXSectionPerAtom(), currentZ, densityCorr, densityFactor, fParticleChange, fStopAndKill, G4cout, G4endl, G4lrint(), G4UniformRand, G4VEmModel::GetAngularDistribution(), G4DynamicParticle::GetKineticEnergy(), G4MaterialCutsCouple::GetMaterial(), G4DynamicParticle::GetMomentumDirection(), G4VEmModel::GetName(), kinEnergy, particle, particleMass, G4VParticleChange::ProposeTrackStatus(), G4VEmAngularDistribution::SampleDirection(), G4VEmModel::SecondaryThreshold(), G4VEmModel::SelectRandomAtom(), SetCurrentElement(), G4ParticleChangeForLoss::SetProposedKineticEnergy(), G4ParticleChangeForLoss::SetProposedMomentumDirection(), SetupForMaterial(), theGamma, and totalEnergy.

00469 {
00470   G4double kineticEnergy = dp->GetKineticEnergy();
00471   if(kineticEnergy < lowKinEnergy) { return; }
00472   G4double cut  = std::min(cutEnergy, kineticEnergy);
00473   G4double emax = std::min(maxEnergy, kineticEnergy);
00474   if(cut >= emax) { return; }
00475 
00476   SetupForMaterial(particle, couple->GetMaterial(), kineticEnergy);
00477 
00478   const G4Element* elm = 
00479     SelectRandomAtom(couple,particle,kineticEnergy,cut,emax);
00480   SetCurrentElement(elm->GetZ());
00481 
00482   kinEnergy   = kineticEnergy;
00483   totalEnergy = kineticEnergy + particleMass;
00484   densityCorr = densityFactor*totalEnergy*totalEnergy;
00485 
00486   //G4double fmax= fMax;
00487   G4bool highe = true;
00488   if(totalEnergy < energyThresholdLPM) { highe = false; }
00489  
00490   G4double xmin = log(cut*cut + densityCorr);
00491   G4double xmax = log(emax*emax  + densityCorr);
00492   G4double gammaEnergy, f, x; 
00493 
00494   do {
00495     x = exp(xmin + G4UniformRand()*(xmax - xmin)) - densityCorr;
00496     if(x < 0.0) { x = 0.0; }
00497     gammaEnergy = sqrt(x);
00498     if(highe) { f = ComputeRelDXSectionPerAtom(gammaEnergy); }
00499     else      { f = ComputeDXSectionPerAtom(gammaEnergy); }
00500 
00501     if ( f > fMax ) {
00502       G4cout << "### G4eBremsstrahlungRelModel Warning: Majoranta exceeded! "
00503              << f << " > " << fMax
00504              << " Egamma(MeV)= " << gammaEnergy
00505              << " Ee(MeV)= " << kineticEnergy
00506              << "  " << GetName()
00507              << G4endl;
00508     }
00509 
00510   } while (f < fMax*G4UniformRand());
00511 
00512   //
00513   // angles of the emitted gamma. ( Z - axis along the parent particle)
00514   // use general interface
00515   //
00516 
00517   G4ThreeVector gammaDirection = 
00518     GetAngularDistribution()->SampleDirection(dp, totalEnergy-gammaEnergy,
00519                                               G4lrint(currentZ), 
00520                                               couple->GetMaterial());
00521 
00522   // create G4DynamicParticle object for the Gamma
00523   G4DynamicParticle* gamma = new G4DynamicParticle(theGamma,gammaDirection,
00524                                                    gammaEnergy);
00525   vdp->push_back(gamma);
00526   
00527   G4double totMomentum = sqrt(kineticEnergy*(totalEnergy + electron_mass_c2));
00528   G4ThreeVector direction = (totMomentum*dp->GetMomentumDirection()
00529                              - gammaEnergy*gammaDirection).unit();
00530 
00531   // energy of primary
00532   G4double finalE = kineticEnergy - gammaEnergy;
00533 
00534   // stop tracking and create new secondary instead of primary
00535   if(gammaEnergy > SecondaryThreshold()) {
00536     fParticleChange->ProposeTrackStatus(fStopAndKill);
00537     fParticleChange->SetProposedKineticEnergy(0.0);
00538     G4DynamicParticle* el = 
00539       new G4DynamicParticle(const_cast<G4ParticleDefinition*>(particle),
00540                             direction, finalE);
00541     vdp->push_back(el);
00542 
00543     // continue tracking
00544   } else {
00545     fParticleChange->SetProposedMomentumDirection(direction);
00546     fParticleChange->SetProposedKineticEnergy(finalE);
00547   }
00548 }

void G4eBremsstrahlungRelModel::SetCurrentElement ( const   G4double  )  [inline, protected]

Definition at line 185 of file G4eBremsstrahlungRelModel.hh.

References currentZ, G4VEmModel::GetCurrentElement(), G4Element::GetfCoulomb(), G4NistManager::GetLOGZ(), G4NistManager::GetZ13(), and nist.

Referenced by ComputeCrossSectionPerAtom(), ComputeDEDXPerVolume(), G4SeltzerBergerModel::SampleSecondaries(), and SampleSecondaries().

00186 {
00187   if(Z != currentZ) {
00188     currentZ = Z;
00189 
00190     G4int iz = G4int(Z);
00191     z13 = nist->GetZ13(iz);
00192     z23 = z13*z13;
00193     lnZ = nist->GetLOGZ(iz);
00194 
00195     if (iz <= 4) {
00196       Fel = Fel_light[iz];  
00197       Finel = Finel_light[iz] ; 
00198     }
00199     else {
00200       Fel = facFel - lnZ/3. ;
00201       Finel = facFinel - 2.*lnZ/3. ;
00202     }
00203 
00204     fCoulomb = GetCurrentElement()->GetfCoulomb();
00205     fMax = Fel-fCoulomb + Finel/currentZ  +  (1.+1./currentZ)/12.;
00206   }
00207 }

void G4eBremsstrahlungRelModel::SetLPMconstant ( G4double  val  )  [inline]

Definition at line 242 of file G4eBremsstrahlungRelModel.hh.

00243 {
00244   fLPMconstant = val;
00245 }

void G4eBremsstrahlungRelModel::SetupForMaterial ( const G4ParticleDefinition *  ,
const G4Material *  ,
G4double   
) [virtual]

Reimplemented from G4VEmModel.

Definition at line 145 of file G4eBremsstrahlungRelModel.cc.

References densityCorr, densityFactor, G4Material::GetElectronDensity(), G4Material::GetRadlen(), kinEnergy, G4VEmModel::LPMFlag(), particleMass, and totalEnergy.

Referenced by ComputeDEDXPerVolume(), G4SeltzerBergerModel::SampleSecondaries(), and SampleSecondaries().

00148 {
00149   densityFactor = mat->GetElectronDensity()*fMigdalConstant;
00150   lpmEnergy = mat->GetRadlen()*fLPMconstant;
00151 
00152   // Threshold for LPM effect (i.e. below which LPM hidden by density effect) 
00153   if (LPMFlag()) {
00154     energyThresholdLPM=sqrt(densityFactor)*lpmEnergy;
00155   } else {
00156      energyThresholdLPM=1.e39;   // i.e. do not use LPM effect
00157   }
00158   // calculate threshold for density effect
00159   kinEnergy   = kineticEnergy;
00160   totalEnergy = kineticEnergy + particleMass;
00161   densityCorr = densityFactor*totalEnergy*totalEnergy;
00162 
00163   // define critical gamma energies (important for integration/dicing)
00164   klpm=totalEnergy*totalEnergy/lpmEnergy;
00165   kp=sqrt(densityCorr);
00166     
00167 }

Field Documentation

G4double G4eBremsstrahlungRelModel::bremFactor [protected]

Definition at line 132 of file G4eBremsstrahlungRelModel.hh.

Referenced by ComputeCrossSectionPerAtom(), ComputeDEDXPerVolume(), and G4SeltzerBergerModel::ComputeDXSectionPerAtom().

G4double G4eBremsstrahlungRelModel::currentZ [protected]

Definition at line 138 of file G4eBremsstrahlungRelModel.hh.

Referenced by ComputeDEDXPerVolume(), G4SeltzerBergerModel::ComputeDXSectionPerAtom(), ComputeDXSectionPerAtom(), G4eBremsstrahlungRelModel(), Initialise(), G4SeltzerBergerModel::SampleSecondaries(), SampleSecondaries(), and SetCurrentElement().

G4double G4eBremsstrahlungRelModel::densityCorr [protected]

Definition at line 142 of file G4eBremsstrahlungRelModel.hh.

Referenced by G4eBremsstrahlungRelModel(), G4SeltzerBergerModel::SampleSecondaries(), SampleSecondaries(), and SetupForMaterial().

G4double G4eBremsstrahlungRelModel::densityFactor [protected]

Definition at line 141 of file G4eBremsstrahlungRelModel.hh.

Referenced by G4eBremsstrahlungRelModel(), G4SeltzerBergerModel::SampleSecondaries(), SampleSecondaries(), and SetupForMaterial().

G4ParticleChangeForLoss* G4eBremsstrahlungRelModel::fParticleChange [protected]

Definition at line 130 of file G4eBremsstrahlungRelModel.hh.

Referenced by G4eBremsstrahlungRelModel(), Initialise(), G4SeltzerBergerModel::SampleSecondaries(), and SampleSecondaries().

G4bool G4eBremsstrahlungRelModel::isElectron [protected]

Definition at line 144 of file G4eBremsstrahlungRelModel.hh.

Referenced by G4SeltzerBergerModel::ComputeDXSectionPerAtom(), and G4SeltzerBergerModel::SampleSecondaries().

G4double G4eBremsstrahlungRelModel::kinEnergy [protected]

Definition at line 136 of file G4eBremsstrahlungRelModel.hh.

Referenced by ComputeCrossSectionPerAtom(), G4SeltzerBergerModel::ComputeDXSectionPerAtom(), G4eBremsstrahlungRelModel(), SampleSecondaries(), and SetupForMaterial().

G4NistManager* G4eBremsstrahlungRelModel::nist [protected]

Definition at line 127 of file G4eBremsstrahlungRelModel.hh.

Referenced by G4eBremsstrahlungRelModel(), and SetCurrentElement().

const G4ParticleDefinition* G4eBremsstrahlungRelModel::particle [protected]

Definition at line 128 of file G4eBremsstrahlungRelModel.hh.

Referenced by ComputeCrossSectionPerAtom(), ComputeDEDXPerVolume(), G4SeltzerBergerModel::SampleSecondaries(), and SampleSecondaries().

G4double G4eBremsstrahlungRelModel::particleMass [protected]

Definition at line 135 of file G4eBremsstrahlungRelModel.hh.

Referenced by G4SeltzerBergerModel::ComputeDXSectionPerAtom(), G4eBremsstrahlungRelModel(), G4SeltzerBergerModel::SampleSecondaries(), SampleSecondaries(), and SetupForMaterial().

G4ParticleDefinition* G4eBremsstrahlungRelModel::theGamma [protected]

Definition at line 129 of file G4eBremsstrahlungRelModel.hh.

Referenced by G4eBremsstrahlungRelModel(), G4SeltzerBergerModel::SampleSecondaries(), and SampleSecondaries().

G4double G4eBremsstrahlungRelModel::totalEnergy [protected]

Definition at line 137 of file G4eBremsstrahlungRelModel.hh.

Referenced by G4SeltzerBergerModel::ComputeDXSectionPerAtom(), ComputeDXSectionPerAtom(), G4eBremsstrahlungRelModel(), G4SeltzerBergerModel::SampleSecondaries(), SampleSecondaries(), and SetupForMaterial().

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