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1 // 1 2 // ******************************************* 3 // * License and Disclaimer 4 // * 5 // * The Geant4 software is copyright of th 6 // * the Geant4 Collaboration. It is provided 7 // * conditions of the Geant4 Software License 8 // * LICENSE and available at http://cern.ch/ 9 // * include a list of copyright holders. 10 // * 11 // * Neither the authors of this software syst 12 // * institutes,nor the agencies providing fin 13 // * work make any representation or warran 14 // * regarding this software system or assum 15 // * use. Please see the license in the file 16 // * for the full disclaimer and the limitatio 17 // * 18 // * This code implementation is the result 19 // * technical work of the GEANT4 collaboratio 20 // * By using, copying, modifying or distri 21 // * any work based on the software) you ag 22 // * use in resulting scientific publicati 23 // * acceptance of all terms of the Geant4 Sof 24 // ******************************************* 25 // 26 // 27 // ------------------------------------------- 28 // 29 // GEANT4 Class header file 30 // 31 // 32 // File name: G4mplIonisationWithDeltaMode 33 // 34 // Author: Vladimir Ivanchenko 35 // 36 // Creation date: 06.09.2005 37 // 38 // Modifications: 39 // 12.08.2007 Changing low energy approximatio 40 // Small bug fixing and refactoring 41 // 13.11.2007 Use low-energy asymptotic from [ 42 // 43 // 44 // ------------------------------------------- 45 // References 46 // [1] Steven P. Ahlen: Energy loss of relativ 47 // S.P. Ahlen, Rev. Mod. Phys 52(1980), p1 48 // [2] K.A. Milton arXiv:hep-ex/0602040 49 // [3] S.P. Ahlen and K. Kinoshita, Phys. Rev. 50 51 52 //....oooOO0OOooo........oooOO0OOooo........oo 53 //....oooOO0OOooo........oooOO0OOooo........oo 54 55 #include "G4mplIonisationWithDeltaModel.hh" 56 #include "Randomize.hh" 57 #include "G4PhysicalConstants.hh" 58 #include "G4SystemOfUnits.hh" 59 #include "G4ParticleChangeForLoss.hh" 60 #include "G4Electron.hh" 61 #include "G4DynamicParticle.hh" 62 #include "G4ProductionCutsTable.hh" 63 #include "G4MaterialCutsCouple.hh" 64 #include "G4Log.hh" 65 #include "G4Pow.hh" 66 67 //....oooOO0OOooo........oooOO0OOooo........oo 68 69 using namespace std; 70 71 std::vector<G4double>* G4mplIonisationWithDelt 72 73 G4mplIonisationWithDeltaModel::G4mplIonisation 74 75 : G4VEmModel(nam),G4VEmFluctuationModel(nam) 76 magCharge(mCharge), 77 twoln10(std::log(100.0)), 78 betalow(0.01), 79 betalim(0.1), 80 beta2lim(betalim*betalim), 81 bg2lim(beta2lim*(1.0 + beta2lim)) 82 { 83 nmpl = G4lrint(std::abs(magCharge) * 2 * fin 84 if(nmpl > 6) { nmpl = 6; } 85 else if(nmpl < 1) { nmpl = 1; } 86 pi_hbarc2_over_mc2 = pi * hbarc * hbarc / el 87 chargeSquare = magCharge * magCharge; 88 dedxlim = 45.*nmpl*nmpl*GeV*cm2/g; 89 fParticleChange = nullptr; 90 theElectron = G4Electron::Electron(); 91 G4cout << "### Monopole ionisation model wit 92 << magCharge/eplus << G4endl; 93 monopole = nullptr; 94 mass = 0.0; 95 } 96 97 //....oooOO0OOooo........oooOO0OOooo........oo 98 99 G4mplIonisationWithDeltaModel::~G4mplIonisatio 100 { 101 if(IsMaster()) { delete dedx0; } 102 } 103 104 //....oooOO0OOooo........oooOO0OOooo........oo 105 106 void G4mplIonisationWithDeltaModel::SetParticl 107 { 108 monopole = p; 109 mass = monopole->GetPDGMass(); 110 G4double emin = 111 std::min(LowEnergyLimit(),0.1*mass*(1./sqr 112 G4double emax = 113 std::max(HighEnergyLimit(),10*mass*(1./sqr 114 SetLowEnergyLimit(emin); 115 SetHighEnergyLimit(emax); 116 } 117 118 //....oooOO0OOooo........oooOO0OOooo........oo 119 120 void 121 G4mplIonisationWithDeltaModel::Initialise(cons 122 cons 123 { 124 if(!monopole) { SetParticle(p); } 125 if(!fParticleChange) { fParticleChange = Get 126 if(IsMaster()) { 127 if(!dedx0) { dedx0 = new std::vector<G4dou 128 G4ProductionCutsTable* theCoupleTable= 129 G4ProductionCutsTable::GetProductionCuts 130 G4int numOfCouples = (G4int)theCoupleTable 131 G4int n = (G4int)dedx0->size(); 132 if(n < numOfCouples) { dedx0->resize(numOf 133 G4Pow* g4calc = G4Pow::GetInstance(); 134 135 // initialise vector assuming low conducti 136 for(G4int i=0; i<numOfCouples; ++i) { 137 138 const G4Material* material = 139 theCoupleTable->GetMaterialCutsCouple( 140 G4double eDensity = material->GetElectro 141 G4double vF2 = 2*electron_Compton_length 142 (*dedx0)[i] = pi_hbarc2_over_mc2*eDensit 143 (G4Log(vF2/fine_structure_const) - 0.5 144 } 145 } 146 } 147 148 //....oooOO0OOooo........oooOO0OOooo........oo 149 150 G4double 151 G4mplIonisationWithDeltaModel::MinEnergyCut(co 152 co 153 { 154 return couple->GetMaterial()->GetIonisation( 155 } 156 157 //....oooOO0OOooo........oooOO0OOooo........oo 158 159 G4double 160 G4mplIonisationWithDeltaModel::ComputeDEDXPerV 161 162 163 164 { 165 if(!monopole) { SetParticle(p); } 166 G4double tmax = MaxSecondaryEnergy(p,kinetic 167 G4double cutEnergy = std::min(tmax, maxEnerg 168 cutEnergy = std::max(LowEnergyLimit(), cutEn 169 G4double tau = kineticEnergy / mass; 170 G4double gam = tau + 1.0; 171 G4double bg2 = tau * (tau + 2.0); 172 G4double beta2 = bg2 / (gam * gam); 173 G4double beta = sqrt(beta2); 174 175 // low-energy asymptotic formula 176 G4double dedx = (*dedx0)[CurrentCouple()->Ge 177 178 // above asymptotic 179 if(beta > betalow) { 180 181 // high energy 182 if(beta >= betalim) { 183 dedx = ComputeDEDXAhlen(material, bg2, c 184 185 } else { 186 G4double dedx1 = (*dedx0)[CurrentCouple( 187 G4double dedx2 = ComputeDEDXAhlen(materi 188 189 // extrapolation between two formula 190 G4double kapa2 = beta - betalow; 191 G4double kapa1 = betalim - beta; 192 dedx = (kapa1*dedx1 + kapa2*dedx2)/(kapa 193 } 194 } 195 return dedx; 196 } 197 198 //....oooOO0OOooo........oooOO0OOooo........oo 199 200 G4double 201 G4mplIonisationWithDeltaModel::ComputeDEDXAhle 202 203 204 { 205 G4double eDensity = material->GetElectronDen 206 G4double eexc = material->GetIonisation()-> 207 208 // Ahlen's formula for nonconductors, [1]p15 209 G4double dedx = 210 0.5*(G4Log(2.0*electron_mass_c2*bg2*cutEne 211 212 // Kazama et al. cross-section correction 213 G4double k = 0.406; 214 if(nmpl > 1) { k = 0.346; } 215 216 // Bloch correction 217 const G4double B[7] = { 0.0, 0.248, 0.672, 1 218 219 dedx += 0.5 * k - B[nmpl]; 220 221 // density effect correction 222 G4double x = G4Log(bg2)/twoln10; 223 dedx -= material->GetIonisation()->DensityCo 224 225 // now compute the total ionization loss 226 dedx *= pi_hbarc2_over_mc2 * eDensity * nmp 227 228 dedx = std::max(dedx, 0.0); 229 return dedx; 230 } 231 232 //....oooOO0OOooo........oooOO0OOooo........oo 233 234 G4double 235 G4mplIonisationWithDeltaModel::ComputeCrossSec 236 con 237 G4d 238 G4d 239 G4d 240 { 241 if(!monopole) { SetParticle(p); } 242 G4double tmax = MaxSecondaryEnergy(p, kineti 243 G4double maxEnergy = std::min(tmax, maxKinEn 244 G4double cutEnergy = std::max(LowEnergyLimit 245 G4double cross = (cutEnergy < maxEnergy) 246 ? (0.5/cutEnergy - 0.5/maxEnergy)*pi_hbarc 247 return cross; 248 } 249 250 //....oooOO0OOooo........oooOO0OOooo........oo 251 252 G4double 253 G4mplIonisationWithDeltaModel::ComputeCrossSec 254 cons 255 G4do 256 G4do 257 G4do 258 G4do 259 { 260 G4double cross = 261 Z*ComputeCrossSectionPerElectron(p,kinetic 262 return cross; 263 } 264 265 //....oooOO0OOooo........oooOO0OOooo........oo 266 267 void 268 G4mplIonisationWithDeltaModel::SampleSecondari 269 270 271 272 273 { 274 G4double kineticEnergy = dp->GetKineticEnerg 275 G4double tmax = MaxSecondaryEnergy(dp->GetDe 276 277 G4double maxKinEnergy = std::min(maxEnergy,t 278 if(minKinEnergy >= maxKinEnergy) { return; } 279 280 //G4cout << "G4mplIonisationWithDeltaModel:: 281 // << kineticEnergy/GeV << " M(GeV)= 282 // << " tmin(MeV)= " << minKinEnergy 283 284 G4double totEnergy = kineticEnergy + mas 285 G4double etot2 = totEnergy*totEnergy 286 G4double beta2 = kineticEnergy*(kine 287 288 // sampling without nuclear size effect 289 G4double q = G4UniformRand(); 290 G4double deltaKinEnergy = minKinEnergy*maxKi 291 /(minKinEnergy*(1.0 - q) + maxKinEnergy*q) 292 293 // delta-electron is produced 294 G4double totMomentum = totEnergy*sqrt(beta2) 295 G4double deltaMomentum = 296 sqrt(deltaKinEnergy * (deltaKinEner 297 G4double cost = deltaKinEnergy * (totEnergy 298 (deltaMomen 299 cost = std::min(cost, 1.0); 300 301 G4double sint = sqrt((1.0 - cost)*(1.0 + cos 302 303 G4double phi = twopi * G4UniformRand() ; 304 305 G4ThreeVector deltaDirection(sint*cos(phi),s 306 G4ThreeVector direction = dp->GetMomentumDir 307 deltaDirection.rotateUz(direction); 308 309 // create G4DynamicParticle object for delta 310 G4DynamicParticle* delta = 311 new G4DynamicParticle(theElectron,deltaDir 312 313 vdp->push_back(delta); 314 315 // Change kinematics of primary particle 316 kineticEnergy -= deltaKinEnergy; 317 G4ThreeVector finalP = direction*totMomentum 318 finalP = finalP.unit(); 319 320 fParticleChange->SetProposedKineticEnergy(ki 321 fParticleChange->SetProposedMomentumDirectio 322 } 323 324 //....oooOO0OOooo........oooOO0OOooo........oo 325 326 G4double G4mplIonisationWithDeltaModel::Sample 327 const G 328 const G 329 const G 330 const G 331 const G 332 const G 333 { 334 G4double siga = Dispersion(couple->GetMateri 335 G4double loss = meanLoss; 336 siga = std::sqrt(siga); 337 G4double twomeanLoss = meanLoss + meanLoss; 338 339 if(twomeanLoss < siga) { 340 G4double x; 341 do { 342 loss = twomeanLoss*G4UniformRand(); 343 x = (loss - meanLoss)/siga; 344 // Loop checking, 07-Aug-2015, Vladimir 345 } while (1.0 - 0.5*x*x < G4UniformRand()); 346 } else { 347 do { 348 loss = G4RandGauss::shoot(meanLoss,siga) 349 // Loop checking, 07-Aug-2015, Vladimir 350 } while (0.0 > loss || loss > twomeanLoss) 351 } 352 return loss; 353 } 354 355 //....oooOO0OOooo........oooOO0OOooo........oo 356 357 G4double 358 G4mplIonisationWithDeltaModel::Dispersion(cons 359 cons 360 const G4double tcut, 361 const G4double tmax, 362 const G4double length) 363 { 364 G4double siga = 0.0; 365 G4double tau = dp->GetKineticEnergy()/mass 366 if(tau > 0.0) { 367 const G4double beta = dp->GetBeta(); 368 siga = (tmax/(beta*beta) - 0.5*tcut) * tw 369 * material->GetElectronDensity() * charg 370 } 371 return siga; 372 } 373 374 //....oooOO0OOooo........oooOO0OOooo........oo 375 376 G4double 377 G4mplIonisationWithDeltaModel::MaxSecondaryEne 378 379 { 380 G4double tau = kinEnergy/mass; 381 return 2.0*electron_mass_c2*tau*(tau + 2.); 382 } 383 384 //....oooOO0OOooo........oooOO0OOooo........oo 385