#include <G4MollerBhabhaModel.hh>
Inheritance diagram for G4MollerBhabhaModel:
Definition at line 63 of file G4MollerBhabhaModel.hh.
G4MollerBhabhaModel::G4MollerBhabhaModel | ( | const G4ParticleDefinition * | p = 0 , |
|
const G4String & | nam = "MollerBhabha" | |||
) |
Definition at line 74 of file G4MollerBhabhaModel.cc.
References G4Electron::Electron(), fParticleChange, SetParticle(), and theElectron.
00076 : G4VEmModel(nam), 00077 particle(0), 00078 isElectron(true), 00079 twoln10(2.0*log(10.0)), 00080 lowLimit(0.02*keV), 00081 isInitialised(false) 00082 { 00083 theElectron = G4Electron::Electron(); 00084 if(p) { SetParticle(p); } 00085 fParticleChange = 0; 00086 }
G4MollerBhabhaModel::~G4MollerBhabhaModel | ( | ) | [virtual] |
G4double G4MollerBhabhaModel::ComputeCrossSectionPerAtom | ( | const G4ParticleDefinition * | , | |
G4double | kineticEnergy, | |||
G4double | Z, | |||
G4double | A, | |||
G4double | cutEnergy, | |||
G4double | maxEnergy | |||
) | [virtual] |
Reimplemented from G4VEmModel.
Definition at line 172 of file G4MollerBhabhaModel.cc.
References ComputeCrossSectionPerElectron().
00178 { 00179 return Z*ComputeCrossSectionPerElectron(p,kineticEnergy,cutEnergy,maxEnergy); 00180 }
G4double G4MollerBhabhaModel::ComputeCrossSectionPerElectron | ( | const G4ParticleDefinition * | , | |
G4double | kineticEnergy, | |||
G4double | cutEnergy, | |||
G4double | maxEnergy | |||
) | [virtual] |
Reimplemented in G4PolarizedMollerBhabhaModel.
Definition at line 119 of file G4MollerBhabhaModel.cc.
References G4InuclParticleNames::gam, isElectron, MaxSecondaryEnergy(), particle, and SetParticle().
Referenced by ComputeCrossSectionPerAtom(), G4PolarizedMollerBhabhaModel::ComputeCrossSectionPerElectron(), and CrossSectionPerVolume().
00123 { 00124 if(!particle) { SetParticle(p); } 00125 00126 G4double cross = 0.0; 00127 G4double tmax = MaxSecondaryEnergy(p, kineticEnergy); 00128 tmax = std::min(maxEnergy, tmax); 00129 00130 if(cutEnergy < tmax) { 00131 00132 G4double xmin = cutEnergy/kineticEnergy; 00133 G4double xmax = tmax/kineticEnergy; 00134 G4double tau = kineticEnergy/electron_mass_c2; 00135 G4double gam = tau + 1.0; 00136 G4double gamma2= gam*gam; 00137 G4double beta2 = tau*(tau + 2)/gamma2; 00138 00139 //Moller (e-e-) scattering 00140 if (isElectron) { 00141 00142 G4double gg = (2.0*gam - 1.0)/gamma2; 00143 cross = ((xmax - xmin)*(1.0 - gg + 1.0/(xmin*xmax) 00144 + 1.0/((1.0-xmin)*(1.0 - xmax))) 00145 - gg*log( xmax*(1.0 - xmin)/(xmin*(1.0 - xmax)) ) ) / beta2; 00146 00147 //Bhabha (e+e-) scattering 00148 } else { 00149 00150 G4double y = 1.0/(1.0 + gam); 00151 G4double y2 = y*y; 00152 G4double y12 = 1.0 - 2.0*y; 00153 G4double b1 = 2.0 - y2; 00154 G4double b2 = y12*(3.0 + y2); 00155 G4double y122= y12*y12; 00156 G4double b4 = y122*y12; 00157 G4double b3 = b4 + y122; 00158 00159 cross = (xmax - xmin)*(1.0/(beta2*xmin*xmax) + b2 00160 - 0.5*b3*(xmin + xmax) 00161 + b4*(xmin*xmin + xmin*xmax + xmax*xmax)/3.0) 00162 - b1*log(xmax/xmin); 00163 } 00164 00165 cross *= twopi_mc2_rcl2/kineticEnergy; 00166 } 00167 return cross; 00168 }
G4double G4MollerBhabhaModel::ComputeDEDXPerVolume | ( | const G4Material * | , | |
const G4ParticleDefinition * | , | |||
G4double | kineticEnergy, | |||
G4double | cutEnergy | |||
) | [virtual] |
Reimplemented from G4VEmModel.
Definition at line 210 of file G4MollerBhabhaModel.cc.
References G4IonisParamMat::DensityCorrection(), G4InuclParticleNames::gam, G4Material::GetElectronDensity(), G4Material::GetIonisation(), G4IonisParamMat::GetMeanExcitationEnergy(), G4Material::GetTotNbOfAtomsPerVolume(), isElectron, MaxSecondaryEnergy(), particle, SetParticle(), and twoln10.
00215 { 00216 if(!particle) { SetParticle(p); } 00217 // calculate the dE/dx due to the ionization by Seltzer-Berger formula 00218 // checl low-energy limit 00219 G4double electronDensity = material->GetElectronDensity(); 00220 00221 G4double Zeff = electronDensity/material->GetTotNbOfAtomsPerVolume(); 00222 G4double th = 0.25*sqrt(Zeff)*keV; 00223 // G4double cut; 00224 // if(isElectron) { cut = std::max(th*0.5, cutEnergy); } 00225 // else { cut = std::max(th, cutEnergy); } 00226 G4double tkin = kineticEnergy; 00227 if (kineticEnergy < th) { tkin = th; } 00228 00229 G4double tau = tkin/electron_mass_c2; 00230 G4double gam = tau + 1.0; 00231 G4double gamma2= gam*gam; 00232 G4double bg2 = tau*(tau + 2); 00233 G4double beta2 = bg2/gamma2; 00234 00235 G4double eexc = material->GetIonisation()->GetMeanExcitationEnergy(); 00236 eexc /= electron_mass_c2; 00237 G4double eexc2 = eexc*eexc; 00238 00239 G4double d = std::min(cut, MaxSecondaryEnergy(p, tkin))/electron_mass_c2; 00240 G4double dedx; 00241 00242 // electron 00243 if (isElectron) { 00244 00245 dedx = log(2.0*(tau + 2.0)/eexc2) - 1.0 - beta2 00246 + log((tau-d)*d) + tau/(tau-d) 00247 + (0.5*d*d + (2.0*tau + 1.)*log(1. - d/tau))/gamma2; 00248 00249 //positron 00250 } else { 00251 00252 G4double d2 = d*d*0.5; 00253 G4double d3 = d2*d/1.5; 00254 G4double d4 = d3*d*0.75; 00255 G4double y = 1.0/(1.0 + gam); 00256 dedx = log(2.0*(tau + 2.0)/eexc2) + log(tau*d) 00257 - beta2*(tau + 2.0*d - y*(3.0*d2 00258 + y*(d - d3 + y*(d2 - tau*d3 + d4))))/tau; 00259 } 00260 00261 //density correction 00262 G4double x = log(bg2)/twoln10; 00263 dedx -= material->GetIonisation()->DensityCorrection(x); 00264 00265 // now you can compute the total ionization loss 00266 dedx *= twopi_mc2_rcl2*electronDensity/beta2; 00267 if (dedx < 0.0) { dedx = 0.0; } 00268 00269 // lowenergy extrapolation 00270 00271 if (kineticEnergy < th) { 00272 x = kineticEnergy/th; 00273 if(x > 0.25) { dedx /= sqrt(x); } 00274 else { dedx *= 1.4*sqrt(x)/(0.1 + x); } 00275 } 00276 return dedx; 00277 }
G4double G4MollerBhabhaModel::CrossSectionPerVolume | ( | const G4Material * | , | |
const G4ParticleDefinition * | , | |||
G4double | kineticEnergy, | |||
G4double | cutEnergy, | |||
G4double | maxEnergy | |||
) | [virtual] |
Reimplemented from G4VEmModel.
Definition at line 184 of file G4MollerBhabhaModel.cc.
References ComputeCrossSectionPerElectron(), and G4Material::GetElectronDensity().
00190 { 00191 G4double eDensity = material->GetElectronDensity(); 00192 return eDensity*ComputeCrossSectionPerElectron(p,kinEnergy,cutEnergy,maxEnergy); 00193 /* 00194 G4double Zeff = eDensity/material->GetTotNbOfAtomsPerVolume(); 00195 G4double th = 0.25*sqrt(Zeff)*keV; 00196 G4double cut; 00197 if(isElectron) { cut = std::max(th*0.5, cutEnergy); } 00198 else { cut = std::max(th, cutEnergy); } 00199 G4double res = 0.0; 00200 // below this threshold no bremsstrahlung 00201 if (kinEnergy > th) { 00202 res = eDensity*ComputeCrossSectionPerElectron(p,kinEnergy,cut,maxEnergy); 00203 } 00204 return res; 00205 */ 00206 }
void G4MollerBhabhaModel::Initialise | ( | const G4ParticleDefinition * | , | |
const G4DataVector & | ||||
) | [virtual] |
Implements G4VEmModel.
Definition at line 105 of file G4MollerBhabhaModel.cc.
References fParticleChange, G4VEmModel::GetParticleChangeForLoss(), particle, and SetParticle().
00107 { 00108 if(!particle) { SetParticle(p); } 00109 00110 if(isInitialised) { return; } 00111 00112 isInitialised = true; 00113 fParticleChange = GetParticleChangeForLoss(); 00114 }
G4double G4MollerBhabhaModel::MaxSecondaryEnergy | ( | const G4ParticleDefinition * | , | |
G4double | kinEnergy | |||
) | [protected, virtual] |
Reimplemented from G4VEmModel.
Definition at line 95 of file G4MollerBhabhaModel.cc.
References isElectron.
Referenced by G4PolarizedMollerBhabhaModel::ComputeCrossSectionPerElectron(), ComputeCrossSectionPerElectron(), and ComputeDEDXPerVolume().
00097 { 00098 G4double tmax = kinEnergy; 00099 if(isElectron) { tmax *= 0.5; } 00100 return tmax; 00101 }
void G4MollerBhabhaModel::SampleSecondaries | ( | std::vector< G4DynamicParticle * > * | , | |
const G4MaterialCutsCouple * | , | |||
const G4DynamicParticle * | , | |||
G4double | tmin, | |||
G4double | maxEnergy | |||
) | [virtual] |
Implements G4VEmModel.
Reimplemented in G4PolarizedMollerBhabhaModel.
Definition at line 281 of file G4MollerBhabhaModel.cc.
References fParticleChange, G4UniformRand, G4InuclParticleNames::gam, G4DynamicParticle::GetKineticEnergy(), G4DynamicParticle::GetMomentumDirection(), isElectron, G4ParticleChangeForLoss::SetProposedKineticEnergy(), G4ParticleChangeForLoss::SetProposedMomentumDirection(), and theElectron.
00286 { 00287 G4double kineticEnergy = dp->GetKineticEnergy(); 00288 //const G4Material* mat = couple->GetMaterial(); 00289 //G4double Zeff = mat->GetElectronDensity()/mat->GetTotNbOfAtomsPerVolume(); 00290 // G4double th = 0.25*sqrt(Zeff)*keV; 00291 G4double tmax; 00292 G4double tmin = cutEnergy; 00293 if(isElectron) { 00294 tmax = 0.5*kineticEnergy; 00295 } else { 00296 tmax = kineticEnergy; 00297 } 00298 if(maxEnergy < tmax) { tmax = maxEnergy; } 00299 if(tmin >= tmax) { return; } 00300 00301 G4double energy = kineticEnergy + electron_mass_c2; 00302 G4double totalMomentum = sqrt(kineticEnergy*(energy + electron_mass_c2)); 00303 G4double xmin = tmin/kineticEnergy; 00304 G4double xmax = tmax/kineticEnergy; 00305 G4double gam = energy/electron_mass_c2; 00306 G4double gamma2 = gam*gam; 00307 G4double beta2 = 1.0 - 1.0/gamma2; 00308 G4double x, z, q, grej; 00309 00310 G4ThreeVector direction = dp->GetMomentumDirection(); 00311 00312 //Moller (e-e-) scattering 00313 if (isElectron) { 00314 00315 G4double gg = (2.0*gam - 1.0)/gamma2; 00316 G4double y = 1.0 - xmax; 00317 grej = 1.0 - gg*xmax + xmax*xmax*(1.0 - gg + (1.0 - gg*y)/(y*y)); 00318 00319 do { 00320 q = G4UniformRand(); 00321 x = xmin*xmax/(xmin*(1.0 - q) + xmax*q); 00322 y = 1.0 - x; 00323 z = 1.0 - gg*x + x*x*(1.0 - gg + (1.0 - gg*y)/(y*y)); 00324 /* 00325 if(z > grej) { 00326 G4cout << "G4MollerBhabhaModel::SampleSecondary Warning! " 00327 << "Majorant " << grej << " < " 00328 << z << " for x= " << x 00329 << " e-e- scattering" 00330 << G4endl; 00331 } 00332 */ 00333 } while(grej * G4UniformRand() > z); 00334 00335 //Bhabha (e+e-) scattering 00336 } else { 00337 00338 G4double y = 1.0/(1.0 + gam); 00339 G4double y2 = y*y; 00340 G4double y12 = 1.0 - 2.0*y; 00341 G4double b1 = 2.0 - y2; 00342 G4double b2 = y12*(3.0 + y2); 00343 G4double y122= y12*y12; 00344 G4double b4 = y122*y12; 00345 G4double b3 = b4 + y122; 00346 00347 y = xmax*xmax; 00348 grej = 1.0 + (y*y*b4 - xmin*xmin*xmin*b3 + y*b2 - xmin*b1)*beta2; 00349 do { 00350 q = G4UniformRand(); 00351 x = xmin*xmax/(xmin*(1.0 - q) + xmax*q); 00352 y = x*x; 00353 z = 1.0 + (y*y*b4 - x*y*b3 + y*b2 - x*b1)*beta2; 00354 /* 00355 if(z > grej) { 00356 G4cout << "G4MollerBhabhaModel::SampleSecondary Warning! " 00357 << "Majorant " << grej << " < " 00358 << z << " for x= " << x 00359 << " e+e- scattering" 00360 << G4endl; 00361 } 00362 */ 00363 } while(grej * G4UniformRand() > z); 00364 } 00365 00366 G4double deltaKinEnergy = x * kineticEnergy; 00367 00368 G4double deltaMomentum = 00369 sqrt(deltaKinEnergy * (deltaKinEnergy + 2.0*electron_mass_c2)); 00370 G4double cost = deltaKinEnergy * (energy + electron_mass_c2) / 00371 (deltaMomentum * totalMomentum); 00372 G4double sint = (1.0 - cost)*(1. + cost); 00373 if(sint > 0.0) { sint = sqrt(sint); } 00374 else { sint = 0.0; } 00375 00376 G4double phi = twopi * G4UniformRand() ; 00377 00378 G4ThreeVector deltaDirection(sint*cos(phi),sint*sin(phi), cost) ; 00379 deltaDirection.rotateUz(direction); 00380 00381 // primary change 00382 kineticEnergy -= deltaKinEnergy; 00383 fParticleChange->SetProposedKineticEnergy(kineticEnergy); 00384 00385 G4ThreeVector dir = totalMomentum*direction - deltaMomentum*deltaDirection; 00386 direction = dir.unit(); 00387 fParticleChange->SetProposedMomentumDirection(direction); 00388 00389 // create G4DynamicParticle object for delta ray 00390 G4DynamicParticle* delta = new G4DynamicParticle(theElectron, 00391 deltaDirection,deltaKinEnergy); 00392 vdp->push_back(delta); 00393 }
void G4MollerBhabhaModel::SetParticle | ( | const G4ParticleDefinition * | p | ) | [inline, protected] |
Definition at line 132 of file G4MollerBhabhaModel.hh.
References isElectron, particle, and theElectron.
Referenced by ComputeCrossSectionPerElectron(), ComputeDEDXPerVolume(), G4MollerBhabhaModel(), and Initialise().
00133 { 00134 particle = p; 00135 if(p != theElectron) { isElectron = false; } 00136 }
Definition at line 114 of file G4MollerBhabhaModel.hh.
Referenced by G4MollerBhabhaModel(), Initialise(), G4PolarizedMollerBhabhaModel::SampleSecondaries(), and SampleSecondaries().
G4bool G4MollerBhabhaModel::isElectron [protected] |
Definition at line 116 of file G4MollerBhabhaModel.hh.
Referenced by ComputeCrossSectionPerElectron(), ComputeDEDXPerVolume(), G4PolarizedMollerBhabhaModel::G4PolarizedMollerBhabhaModel(), MaxSecondaryEnergy(), G4PolarizedMollerBhabhaModel::SampleSecondaries(), SampleSecondaries(), and SetParticle().
G4double G4MollerBhabhaModel::lowLimit [protected] |
const G4ParticleDefinition* G4MollerBhabhaModel::particle [protected] |
Definition at line 112 of file G4MollerBhabhaModel.hh.
Referenced by ComputeCrossSectionPerElectron(), ComputeDEDXPerVolume(), Initialise(), and SetParticle().
G4ParticleDefinition* G4MollerBhabhaModel::theElectron [protected] |
Definition at line 113 of file G4MollerBhabhaModel.hh.
Referenced by G4MollerBhabhaModel(), G4PolarizedMollerBhabhaModel::G4PolarizedMollerBhabhaModel(), G4PolarizedMollerBhabhaModel::SampleSecondaries(), SampleSecondaries(), and SetParticle().
G4double G4MollerBhabhaModel::twoln10 [protected] |