#include <G4IonFluctuations.hh>
Inheritance diagram for G4IonFluctuations:
Public Member Functions | |
| G4IonFluctuations (const G4String &nam="IonFluc") | |
| virtual | ~G4IonFluctuations () |
| G4double | SampleFluctuations (const G4Material *, const G4DynamicParticle *, G4double &tmax, G4double &length, G4double &meanLoss) |
| G4double | Dispersion (const G4Material *, const G4DynamicParticle *, G4double &tmax, G4double &length) |
| void | InitialiseMe (const G4ParticleDefinition *) |
| void | SetParticleAndCharge (const G4ParticleDefinition *, G4double q2) |
Definition at line 59 of file G4IonFluctuations.hh.
| G4IonFluctuations::G4IonFluctuations | ( | const G4String & | nam = "IonFluc" |
) |
Definition at line 70 of file G4IonFluctuations.cc.
00071 : G4VEmFluctuationModel(nam), 00072 particle(0), 00073 particleMass(proton_mass_c2), 00074 charge(1.0), 00075 chargeSquare(1.0), 00076 effChargeSquare(1.0), 00077 parameter(10.0*CLHEP::MeV/CLHEP::proton_mass_c2), 00078 minNumberInteractionsBohr(0.0), 00079 theBohrBeta2(50.0*keV/CLHEP::proton_mass_c2), 00080 minFraction(0.2), 00081 xmin(0.2), 00082 minLoss(0.001*eV) 00083 { 00084 kineticEnergy = 0.0; 00085 beta2 = 0.0; 00086 }
| G4IonFluctuations::~G4IonFluctuations | ( | ) | [virtual] |
| G4double G4IonFluctuations::Dispersion | ( | const G4Material * | , | |
| const G4DynamicParticle * | , | |||
| G4double & | tmax, | |||
| G4double & | length | |||
| ) | [virtual] |
Implements G4VEmFluctuationModel.
Definition at line 170 of file G4IonFluctuations.cc.
References G4Material::GetElectronDensity(), G4DynamicParticle::GetKineticEnergy(), and G4Material::GetTotNbOfAtomsPerVolume().
Referenced by SampleFluctuations().
00174 { 00175 kineticEnergy = dp->GetKineticEnergy(); 00176 G4double etot = kineticEnergy + particleMass; 00177 beta2 = kineticEnergy*(kineticEnergy + 2.*particleMass)/(etot*etot); 00178 00179 G4double electronDensity = material->GetElectronDensity(); 00180 00181 /* 00182 G4cout << "e= " << kineticEnergy << " m= " << particleMass 00183 << " tmax= " << tmax << " l= " << length 00184 << " q^2= " << effChargeSquare << " beta2=" << beta2<< G4endl; 00185 */ 00186 G4double siga = (1. - beta2*0.5)*tmax*length*electronDensity* 00187 twopi_mc2_rcl2*chargeSquare/beta2; 00188 00189 // Low velocity - additional ion charge fluctuations according to 00190 // Q.Yang et al., NIM B61(1991)149-155. 00191 //G4cout << "sigE= " << sqrt(siga) << " charge= " << charge <<G4endl; 00192 00193 G4double Z = electronDensity/material->GetTotNbOfAtomsPerVolume(); 00194 00195 G4double fac = Factor(material, Z); 00196 00197 // heavy ion correction 00198 // G4double f1 = 1.065e-4*chargeSquare; 00199 // if(beta2 > theBohrBeta2) f1/= beta2; 00200 // else f1/= theBohrBeta2; 00201 // if(f1 > 2.5) f1 = 2.5; 00202 // fac *= (1.0 + f1); 00203 00204 // taking into account the cut 00205 G4double fac_cut = 1.0 + (fac - 1.0)*2.0*electron_mass_c2*beta2/(tmax*(1.0 - beta2)); 00206 if(fac_cut > 0.01 && fac > 0.01) { 00207 siga *= fac_cut; 00208 } 00209 00210 //G4cout << "siga(keV)= " << sqrt(siga)/keV << " fac= " << fac 00211 // << " f1= " << f1 << G4endl; 00212 00213 return siga; 00214 }
| void G4IonFluctuations::InitialiseMe | ( | const G4ParticleDefinition * | ) | [virtual] |
Reimplemented from G4VEmFluctuationModel.
Definition at line 95 of file G4IonFluctuations.cc.
References G4ParticleDefinition::GetPDGCharge(), G4ParticleDefinition::GetPDGMass(), and G4UniversalFluctuation::InitialiseMe().
00096 { 00097 particle = part; 00098 particleMass = part->GetPDGMass(); 00099 charge = part->GetPDGCharge()/eplus; 00100 chargeSquare = charge*charge; 00101 effChargeSquare= chargeSquare; 00102 uniFluct.InitialiseMe(part); 00103 }
| G4double G4IonFluctuations::SampleFluctuations | ( | const G4Material * | , | |
| const G4DynamicParticle * | , | |||
| G4double & | tmax, | |||
| G4double & | length, | |||
| G4double & | meanLoss | |||
| ) | [virtual] |
Implements G4VEmFluctuationModel.
Definition at line 107 of file G4IonFluctuations.cc.
References Dispersion(), G4UniformRand, G4InuclParticleNames::gam, G4DynamicParticle::GetKineticEnergy(), and G4UniversalFluctuation::SampleFluctuations().
00112 { 00113 // G4cout << "### meanLoss= " << meanLoss << G4endl; 00114 if(meanLoss <= minLoss) return meanLoss; 00115 00116 //G4cout << "G4IonFluctuations::SampleFluctuations E(MeV)= " << dp->GetKineticEnergy() 00117 // << " Elim(MeV)= " << parameter*charge*particleMass << G4endl; 00118 00119 // Vavilov fluctuations 00120 if(dp->GetKineticEnergy() > parameter*charge*particleMass) { 00121 return uniFluct.SampleFluctuations(material,dp,tmax,length,meanLoss); 00122 } 00123 00124 G4double siga = Dispersion(material,dp,tmax,length); 00125 G4double loss = meanLoss; 00126 00127 //G4cout << "### siga= " << sqrt(siga) << " navr= " << navr << G4endl; 00128 00129 // Gaussian fluctuation 00130 00131 // Increase fluctuations for big fractional energy loss 00132 //G4cout << "siga= " << siga << G4endl; 00133 if ( meanLoss > minFraction*kineticEnergy ) { 00134 G4double gam = (kineticEnergy - meanLoss)/particleMass + 1.0; 00135 G4double b2 = 1.0 - 1.0/(gam*gam); 00136 if(b2 < xmin*beta2) b2 = xmin*beta2; 00137 G4double x = b2/beta2; 00138 G4double x3 = 1.0/(x*x*x); 00139 siga *= 0.25*(1.0 + x)*(x3 + (1.0/b2 - 0.5)/(1.0/beta2 - 0.5) ); 00140 } 00141 siga = sqrt(siga); 00142 G4double sn = meanLoss/siga; 00143 G4double twomeanLoss = meanLoss + meanLoss; 00144 // G4cout << "siga= " << siga << " sn= " << sn << G4endl; 00145 00146 // thick target case 00147 if (sn >= 2.0) { 00148 00149 do { 00150 loss = G4RandGauss::shoot(meanLoss,siga); 00151 } while (0.0 > loss || twomeanLoss < loss); 00152 00153 // Gamma distribution 00154 } else if(sn > 0.1) { 00155 00156 G4double neff = sn*sn; 00157 loss = meanLoss*CLHEP::RandGamma::shoot(neff,1.0)/neff; 00158 00159 // uniform distribution for very small steps 00160 } else { 00161 loss = twomeanLoss*G4UniformRand(); 00162 } 00163 00164 //G4cout << "meanLoss= " << meanLoss << " loss= " << loss << G4endl; 00165 return loss; 00166 }
| void G4IonFluctuations::SetParticleAndCharge | ( | const G4ParticleDefinition * | , | |
| G4double | q2 | |||
| ) | [virtual] |
Reimplemented from G4VEmFluctuationModel.
Definition at line 431 of file G4IonFluctuations.cc.
References G4ParticleDefinition::GetPDGCharge(), G4ParticleDefinition::GetPDGMass(), and G4UniversalFluctuation::SetParticleAndCharge().
00433 { 00434 if(part != particle) { 00435 particle = part; 00436 particleMass = part->GetPDGMass(); 00437 charge = part->GetPDGCharge()/eplus; 00438 chargeSquare = charge*charge; 00439 } 00440 effChargeSquare = q2; 00441 uniFluct.SetParticleAndCharge(part, q2); 00442 }
1.4.7