[1316] | 1 | // |
---|
| 2 | // ******************************************************************** |
---|
| 3 | // * License and Disclaimer * |
---|
| 4 | // * * |
---|
| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
| 7 | // * conditions of the Geant4 Software License, included in the file * |
---|
| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
| 9 | // * include a list of copyright holders. * |
---|
| 10 | // * * |
---|
| 11 | // * Neither the authors of this software system, nor their employing * |
---|
| 12 | // * institutes,nor the agencies providing financial support for this * |
---|
| 13 | // * work make any representation or warranty, express or implied, * |
---|
| 14 | // * regarding this software system or assume any liability for its * |
---|
| 15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
| 16 | // * for the full disclaimer and the limitation of liability. * |
---|
| 17 | // * * |
---|
| 18 | // * This code implementation is the result of the scientific and * |
---|
| 19 | // * technical work of the GEANT4 collaboration. * |
---|
| 20 | // * By using, copying, modifying or distributing the software (or * |
---|
| 21 | // * any work based on the software) you agree to acknowledge its * |
---|
| 22 | // * use in resulting scientific publications, and indicate your * |
---|
| 23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
| 24 | // ******************************************************************** |
---|
| 25 | // |
---|
[1340] | 26 | // $Id: G4Penelope08ComptonModel.cc,v 1.7 2010/07/28 07:09:16 pandola Exp $ |
---|
[1347] | 27 | // GEANT4 tag $Name: geant4-09-04-ref-00 $ |
---|
[1316] | 28 | // |
---|
| 29 | // Author: Luciano Pandola |
---|
| 30 | // |
---|
| 31 | // History: |
---|
| 32 | // -------- |
---|
| 33 | // 15 Feb 2010 L Pandola Implementation |
---|
| 34 | // 18 Mar 2010 L. Pandola Removed GetAtomsPerMolecule(), now demanded |
---|
| 35 | // to G4PenelopeOscillatorManager |
---|
| 36 | // |
---|
| 37 | #include "G4Penelope08ComptonModel.hh" |
---|
| 38 | #include "G4ParticleDefinition.hh" |
---|
| 39 | #include "G4MaterialCutsCouple.hh" |
---|
| 40 | #include "G4ProductionCutsTable.hh" |
---|
| 41 | #include "G4DynamicParticle.hh" |
---|
| 42 | #include "G4VEMDataSet.hh" |
---|
| 43 | #include "G4PhysicsTable.hh" |
---|
| 44 | #include "G4PhysicsLogVector.hh" |
---|
| 45 | #include "G4AtomicTransitionManager.hh" |
---|
| 46 | #include "G4AtomicShell.hh" |
---|
| 47 | #include "G4Gamma.hh" |
---|
| 48 | #include "G4Electron.hh" |
---|
| 49 | #include "G4PenelopeOscillatorManager.hh" |
---|
| 50 | #include "G4PenelopeOscillator.hh" |
---|
| 51 | |
---|
| 52 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 53 | |
---|
| 54 | |
---|
| 55 | G4Penelope08ComptonModel::G4Penelope08ComptonModel(const G4ParticleDefinition*, |
---|
| 56 | const G4String& nam) |
---|
| 57 | :G4VEmModel(nam),isInitialised(false),oscManager(0) |
---|
| 58 | { |
---|
| 59 | fIntrinsicLowEnergyLimit = 100.0*eV; |
---|
| 60 | fIntrinsicHighEnergyLimit = 100.0*GeV; |
---|
| 61 | // SetLowEnergyLimit(fIntrinsicLowEnergyLimit); |
---|
| 62 | SetHighEnergyLimit(fIntrinsicHighEnergyLimit); |
---|
| 63 | // |
---|
| 64 | oscManager = G4PenelopeOscillatorManager::GetOscillatorManager(); |
---|
| 65 | |
---|
| 66 | verboseLevel= 0; |
---|
| 67 | // Verbosity scale: |
---|
| 68 | // 0 = nothing |
---|
| 69 | // 1 = warning for energy non-conservation |
---|
| 70 | // 2 = details of energy budget |
---|
| 71 | // 3 = calculation of cross sections, file openings, sampling of atoms |
---|
| 72 | // 4 = entering in methods |
---|
| 73 | |
---|
| 74 | //by default, the model will use atomic deexcitation |
---|
| 75 | SetDeexcitationFlag(true); |
---|
| 76 | ActivateAuger(false); |
---|
| 77 | |
---|
| 78 | } |
---|
| 79 | |
---|
| 80 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 81 | |
---|
| 82 | G4Penelope08ComptonModel::~G4Penelope08ComptonModel() |
---|
| 83 | {;} |
---|
| 84 | |
---|
| 85 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 86 | |
---|
| 87 | void G4Penelope08ComptonModel::Initialise(const G4ParticleDefinition*, |
---|
| 88 | const G4DataVector&) |
---|
| 89 | { |
---|
| 90 | if (verboseLevel > 3) |
---|
| 91 | G4cout << "Calling G4Penelope08ComptonModel::Initialise()" << G4endl; |
---|
| 92 | |
---|
| 93 | if (verboseLevel > 0) { |
---|
| 94 | G4cout << "Penelope Compton model is initialized " << G4endl |
---|
| 95 | << "Energy range: " |
---|
| 96 | << LowEnergyLimit() / keV << " keV - " |
---|
| 97 | << HighEnergyLimit() / GeV << " GeV" |
---|
| 98 | << G4endl; |
---|
| 99 | } |
---|
| 100 | |
---|
| 101 | if(isInitialised) return; |
---|
| 102 | fParticleChange = GetParticleChangeForGamma(); |
---|
| 103 | isInitialised = true; |
---|
| 104 | } |
---|
| 105 | |
---|
| 106 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 107 | |
---|
| 108 | G4double G4Penelope08ComptonModel::CrossSectionPerVolume(const G4Material* material, |
---|
| 109 | const G4ParticleDefinition* p, |
---|
| 110 | G4double energy, |
---|
| 111 | G4double, |
---|
| 112 | G4double) |
---|
| 113 | { |
---|
| 114 | // Penelope model to calculate the Compton scattering cross section: |
---|
| 115 | // D. Brusa et al., Nucl. Instrum. Meth. A 379 (1996) 167 |
---|
| 116 | // |
---|
| 117 | // The cross section for Compton scattering is calculated according to the Klein-Nishina |
---|
| 118 | // formula for energy > 5 MeV. |
---|
| 119 | // For E < 5 MeV it is used a parametrization for the differential cross-section dSigma/dOmega, |
---|
| 120 | // which is integrated numerically in cos(theta), G4Penelope08ComptonModel::DifferentialCrossSection(). |
---|
| 121 | // The parametrization includes the J(p) |
---|
| 122 | // distribution profiles for the atomic shells, that are tabulated from Hartree-Fock calculations |
---|
| 123 | // from F. Biggs et al., At. Data Nucl. Data Tables 16 (1975) 201 |
---|
| 124 | // |
---|
| 125 | if (verboseLevel > 3) |
---|
| 126 | G4cout << "Calling CrossSectionPerVolume() of G4Penelope08ComptonModel" << G4endl; |
---|
| 127 | SetupForMaterial(p, material, energy); |
---|
| 128 | |
---|
| 129 | //Retrieve the oscillator table for this material |
---|
| 130 | G4PenelopeOscillatorTable* theTable = oscManager->GetOscillatorTableCompton(material); |
---|
| 131 | |
---|
| 132 | G4double cs = 0; |
---|
| 133 | |
---|
| 134 | if (energy < 5*MeV) //explicit calculation for E < 5 MeV |
---|
| 135 | { |
---|
| 136 | size_t numberOfOscillators = theTable->size(); |
---|
| 137 | for (size_t i=0;i<numberOfOscillators;i++) |
---|
| 138 | { |
---|
| 139 | G4PenelopeOscillator* theOsc = (*theTable)[i]; |
---|
| 140 | //sum contributions coming from each oscillator |
---|
| 141 | cs += OscillatorTotalCrossSection(energy,theOsc); |
---|
| 142 | } |
---|
| 143 | } |
---|
| 144 | else //use Klein-Nishina for E>5 MeV |
---|
| 145 | cs = KleinNishinaCrossSection(energy,material); |
---|
| 146 | |
---|
| 147 | //cross sections are in units of pi*classic_electr_radius^2 |
---|
| 148 | cs *= pi*classic_electr_radius*classic_electr_radius; |
---|
| 149 | |
---|
| 150 | //Now, cs is the cross section *per molecule*, let's calculate the |
---|
| 151 | //cross section per volume |
---|
| 152 | |
---|
| 153 | G4double atomDensity = material->GetTotNbOfAtomsPerVolume(); |
---|
| 154 | G4double atPerMol = oscManager->GetAtomsPerMolecule(material); |
---|
| 155 | |
---|
| 156 | if (verboseLevel > 3) |
---|
| 157 | G4cout << "Material " << material->GetName() << " has " << atPerMol << |
---|
| 158 | "atoms per molecule" << G4endl; |
---|
| 159 | |
---|
| 160 | G4double moleculeDensity = 0.; |
---|
| 161 | |
---|
| 162 | if (atPerMol) |
---|
| 163 | moleculeDensity = atomDensity/atPerMol; |
---|
| 164 | |
---|
| 165 | G4double csvolume = cs*moleculeDensity; |
---|
| 166 | |
---|
| 167 | if (verboseLevel > 2) |
---|
| 168 | G4cout << "Compton mean free path at " << energy/keV << " keV for material " << |
---|
| 169 | material->GetName() << " = " << (1./csvolume)/mm << " mm" << G4endl; |
---|
| 170 | return csvolume; |
---|
| 171 | } |
---|
| 172 | |
---|
| 173 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 174 | |
---|
| 175 | //This is a dummy method. Never inkoved by the tracking, it just issues |
---|
| 176 | //a warning if one tries to get Cross Sections per Atom via the |
---|
| 177 | //G4EmCalculator. |
---|
| 178 | G4double G4Penelope08ComptonModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition*, |
---|
| 179 | G4double, |
---|
| 180 | G4double, |
---|
| 181 | G4double, |
---|
| 182 | G4double, |
---|
| 183 | G4double) |
---|
| 184 | { |
---|
| 185 | G4cout << "*** G4Penelope08ComptonModel -- WARNING ***" << G4endl; |
---|
| 186 | G4cout << "Penelope Compton model does not calculate cross section _per atom_ " << G4endl; |
---|
| 187 | G4cout << "so the result is always zero. For physics values, please invoke " << G4endl; |
---|
| 188 | G4cout << "GetCrossSectionPerVolume() or GetMeanFreePath() via the G4EmCalculator" << G4endl; |
---|
| 189 | return 0; |
---|
| 190 | } |
---|
| 191 | |
---|
| 192 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 193 | |
---|
| 194 | void G4Penelope08ComptonModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect, |
---|
| 195 | const G4MaterialCutsCouple* couple, |
---|
| 196 | const G4DynamicParticle* aDynamicGamma, |
---|
| 197 | G4double, |
---|
| 198 | G4double) |
---|
| 199 | { |
---|
| 200 | |
---|
| 201 | // Penelope model to sample the Compton scattering final state. |
---|
| 202 | // D. Brusa et al., Nucl. Instrum. Meth. A 379 (1996) 167 |
---|
| 203 | // The model determines also the original shell from which the electron is expelled, |
---|
| 204 | // in order to produce fluorescence de-excitation (from G4DeexcitationManager) |
---|
| 205 | // |
---|
| 206 | // The final state for Compton scattering is calculated according to the Klein-Nishina |
---|
| 207 | // formula for energy > 5 MeV. In this case, the Doppler broadening is negligible and |
---|
| 208 | // one can assume that the target electron is at rest. |
---|
| 209 | // For E < 5 MeV it is used the parametrization for the differential cross-section dSigma/dOmega, |
---|
| 210 | // to sample the scattering angle and the energy of the emerging electron, which is |
---|
| 211 | // G4Penelope08ComptonModel::DifferentialCrossSection(). The rejection method is |
---|
| 212 | // used to sample cos(theta). The efficiency increases monotonically with photon energy and is |
---|
| 213 | // nearly independent on the Z; typical values are 35%, 80% and 95% for 1 keV, 1 MeV and 10 MeV, |
---|
| 214 | // respectively. |
---|
| 215 | // The parametrization includes the J(p) distribution profiles for the atomic shells, that are |
---|
| 216 | // tabulated |
---|
| 217 | // from Hartree-Fock calculations from F. Biggs et al., At. Data Nucl. Data Tables 16 (1975) 201. |
---|
| 218 | // Doppler broadening is included. |
---|
| 219 | // |
---|
| 220 | |
---|
| 221 | if (verboseLevel > 3) |
---|
| 222 | G4cout << "Calling SampleSecondaries() of G4Penelope08ComptonModel" << G4endl; |
---|
| 223 | |
---|
| 224 | G4double photonEnergy0 = aDynamicGamma->GetKineticEnergy(); |
---|
| 225 | |
---|
| 226 | if (photonEnergy0 <= fIntrinsicLowEnergyLimit) |
---|
| 227 | { |
---|
| 228 | fParticleChange->ProposeTrackStatus(fStopAndKill); |
---|
| 229 | fParticleChange->SetProposedKineticEnergy(0.); |
---|
| 230 | fParticleChange->ProposeLocalEnergyDeposit(photonEnergy0); |
---|
| 231 | return ; |
---|
| 232 | } |
---|
| 233 | |
---|
| 234 | G4ParticleMomentum photonDirection0 = aDynamicGamma->GetMomentumDirection(); |
---|
| 235 | const G4Material* material = couple->GetMaterial(); |
---|
| 236 | |
---|
| 237 | G4PenelopeOscillatorTable* theTable = oscManager->GetOscillatorTableCompton(material); |
---|
| 238 | |
---|
| 239 | const G4int nmax = 64; |
---|
| 240 | G4double rn[nmax],pac[nmax]; |
---|
| 241 | |
---|
| 242 | G4double S=0.0; |
---|
| 243 | G4double epsilon = 0.0; |
---|
| 244 | G4double cosTheta = 1.0; |
---|
| 245 | G4double hartreeFunc = 0.0; |
---|
| 246 | G4double oscStren = 0.0; |
---|
| 247 | size_t numberOfOscillators = theTable->size(); |
---|
| 248 | size_t targetOscillator = 0; |
---|
| 249 | G4double ionEnergy = 0.0*eV; |
---|
| 250 | |
---|
| 251 | G4double ek = photonEnergy0/electron_mass_c2; |
---|
| 252 | G4double ek2 = 2.*ek+1.0; |
---|
| 253 | G4double eks = ek*ek; |
---|
| 254 | G4double ek1 = eks-ek2-1.0; |
---|
| 255 | |
---|
| 256 | G4double taumin = 1.0/ek2; |
---|
| 257 | G4double a1 = std::log(ek2); |
---|
| 258 | G4double a2 = a1+2.0*ek*(1.0+ek)/(ek2*ek2); |
---|
| 259 | |
---|
| 260 | G4double TST = 0; |
---|
| 261 | G4double tau = 0.; |
---|
| 262 | |
---|
| 263 | //If the incoming photon is above 5 MeV, the quicker approach based on the |
---|
| 264 | //pure Klein-Nishina formula is used |
---|
| 265 | if (photonEnergy0 > 5*MeV) |
---|
| 266 | { |
---|
| 267 | do{ |
---|
| 268 | do{ |
---|
| 269 | if ((a2*G4UniformRand()) < a1) |
---|
| 270 | tau = std::pow(taumin,G4UniformRand()); |
---|
| 271 | else |
---|
| 272 | tau = std::sqrt(1.0+G4UniformRand()*(taumin*taumin-1.0)); |
---|
| 273 | //rejection function |
---|
| 274 | TST = (1.0+tau*(ek1+tau*(ek2+tau*eks)))/(eks*tau*(1.0+tau*tau)); |
---|
| 275 | }while (G4UniformRand()> TST); |
---|
| 276 | epsilon=tau; |
---|
| 277 | cosTheta = 1.0 - (1.0-tau)/(ek*tau); |
---|
| 278 | |
---|
| 279 | //Target shell electrons |
---|
| 280 | TST = oscManager->GetTotalZ(material)*G4UniformRand(); |
---|
| 281 | targetOscillator = numberOfOscillators-1; //last level |
---|
| 282 | S=0.0; |
---|
| 283 | G4bool levelFound = false; |
---|
| 284 | for (size_t j=0;j<numberOfOscillators && !levelFound; j++) |
---|
| 285 | { |
---|
| 286 | S += (*theTable)[j]->GetOscillatorStrength(); |
---|
| 287 | if (S > TST) |
---|
| 288 | { |
---|
| 289 | targetOscillator = j; |
---|
| 290 | levelFound = true; |
---|
| 291 | } |
---|
| 292 | } |
---|
| 293 | //check whether the level is valid |
---|
| 294 | ionEnergy = (*theTable)[targetOscillator]->GetIonisationEnergy(); |
---|
| 295 | }while((epsilon*photonEnergy0-photonEnergy0+ionEnergy) >0); |
---|
| 296 | } |
---|
| 297 | else //photonEnergy0 < 5 MeV |
---|
| 298 | { |
---|
| 299 | //Incoherent scattering function for theta=PI |
---|
| 300 | G4double s0=0.0; |
---|
| 301 | G4double pzomc=0.0; |
---|
| 302 | G4double rni=0.0; |
---|
| 303 | G4double aux=0.0; |
---|
| 304 | for (size_t i=0;i<numberOfOscillators;i++) |
---|
| 305 | { |
---|
| 306 | ionEnergy = (*theTable)[i]->GetIonisationEnergy(); |
---|
| 307 | if (photonEnergy0 > ionEnergy) |
---|
| 308 | { |
---|
| 309 | G4double aux = photonEnergy0*(photonEnergy0-ionEnergy)*2.0; |
---|
| 310 | hartreeFunc = (*theTable)[i]->GetHartreeFactor(); |
---|
| 311 | oscStren = (*theTable)[i]->GetOscillatorStrength(); |
---|
| 312 | pzomc = hartreeFunc*(aux-electron_mass_c2*ionEnergy)/ |
---|
| 313 | (electron_mass_c2*std::sqrt(2.0*aux+ionEnergy*ionEnergy)); |
---|
| 314 | if (pzomc > 0) |
---|
| 315 | rni = 1.0-0.5*std::exp(0.5-(std::sqrt(0.5)+std::sqrt(2.0)*pzomc)* |
---|
| 316 | (std::sqrt(0.5)+std::sqrt(2.0)*pzomc)); |
---|
| 317 | else |
---|
| 318 | rni = 0.5*std::exp(0.5-(std::sqrt(0.5)-std::sqrt(2.0)*pzomc)* |
---|
| 319 | (std::sqrt(0.5)-std::sqrt(2.0)*pzomc)); |
---|
| 320 | s0 += oscStren*rni; |
---|
| 321 | } |
---|
| 322 | } |
---|
| 323 | //Sampling tau |
---|
| 324 | G4double cdt1 = 0.; |
---|
| 325 | do |
---|
| 326 | { |
---|
| 327 | if ((G4UniformRand()*a2) < a1) |
---|
| 328 | tau = std::pow(taumin,G4UniformRand()); |
---|
| 329 | else |
---|
| 330 | tau = std::sqrt(1.0+G4UniformRand()*(taumin*taumin-1.0)); |
---|
| 331 | cdt1 = (1.0-tau)/(ek*tau); |
---|
| 332 | //Incoherent scattering function |
---|
| 333 | S = 0.; |
---|
| 334 | for (size_t i=0;i<numberOfOscillators;i++) |
---|
| 335 | { |
---|
| 336 | ionEnergy = (*theTable)[i]->GetIonisationEnergy(); |
---|
| 337 | if (photonEnergy0 > ionEnergy) //sum only on excitable levels |
---|
| 338 | { |
---|
| 339 | aux = photonEnergy0*(photonEnergy0-ionEnergy)*cdt1; |
---|
| 340 | hartreeFunc = (*theTable)[i]->GetHartreeFactor(); |
---|
| 341 | oscStren = (*theTable)[i]->GetOscillatorStrength(); |
---|
| 342 | pzomc = hartreeFunc*(aux-electron_mass_c2*ionEnergy)/ |
---|
| 343 | (electron_mass_c2*std::sqrt(2.0*aux+ionEnergy*ionEnergy)); |
---|
| 344 | if (pzomc > 0) |
---|
| 345 | rn[i] = 1.0-0.5*std::exp(0.5-(std::sqrt(0.5)+std::sqrt(2.0)*pzomc)* |
---|
| 346 | (std::sqrt(0.5)+std::sqrt(2.0)*pzomc)); |
---|
| 347 | else |
---|
| 348 | rn[i] = 0.5*std::exp(0.5-(std::sqrt(0.5)-std::sqrt(2.0)*pzomc)* |
---|
| 349 | (std::sqrt(0.5)-std::sqrt(2.0)*pzomc)); |
---|
| 350 | S += oscStren*rn[i]; |
---|
| 351 | pac[i] = S; |
---|
| 352 | } |
---|
| 353 | else |
---|
| 354 | pac[i] = S-1e-6; |
---|
| 355 | } |
---|
| 356 | //Rejection function |
---|
| 357 | TST = S*(1.0+tau*(ek1+tau*(ek2+tau*eks)))/(eks*tau*(1.0+tau*tau)); |
---|
| 358 | }while ((G4UniformRand()*s0) > TST); |
---|
| 359 | |
---|
| 360 | cosTheta = 1.0 - cdt1; |
---|
| 361 | G4double fpzmax=0.0,fpz=0.0; |
---|
| 362 | G4double A=0.0; |
---|
| 363 | //Target electron shell |
---|
| 364 | do |
---|
| 365 | { |
---|
| 366 | do |
---|
| 367 | { |
---|
| 368 | TST = S*G4UniformRand(); |
---|
| 369 | targetOscillator = numberOfOscillators-1; //last level |
---|
| 370 | G4bool levelFound = false; |
---|
| 371 | for (size_t i=0;i<numberOfOscillators && !levelFound;i++) |
---|
| 372 | { |
---|
| 373 | if (pac[i]>TST) |
---|
| 374 | { |
---|
| 375 | targetOscillator = i; |
---|
| 376 | levelFound = true; |
---|
| 377 | } |
---|
| 378 | } |
---|
| 379 | A = G4UniformRand()*rn[targetOscillator]; |
---|
| 380 | hartreeFunc = (*theTable)[targetOscillator]->GetHartreeFactor(); |
---|
| 381 | oscStren = (*theTable)[targetOscillator]->GetOscillatorStrength(); |
---|
| 382 | if (A < 0.5) |
---|
| 383 | pzomc = (std::sqrt(0.5)-std::sqrt(0.5-std::log(2.0*A)))/ |
---|
| 384 | (std::sqrt(2.0)*hartreeFunc); |
---|
| 385 | else |
---|
| 386 | pzomc = (std::sqrt(0.5-std::log(2.0-2.0*A))-std::sqrt(0.5))/ |
---|
| 387 | (std::sqrt(2.0)*hartreeFunc); |
---|
| 388 | } while (pzomc < -1); |
---|
| 389 | |
---|
| 390 | // F(EP) rejection |
---|
| 391 | G4double XQC = 1.0+tau*(tau-2.0*cosTheta); |
---|
| 392 | G4double AF = std::sqrt(XQC)*(1.0+tau*(tau-cosTheta)/XQC); |
---|
| 393 | if (AF > 0) |
---|
| 394 | fpzmax = 1.0+AF*0.2; |
---|
| 395 | else |
---|
| 396 | fpzmax = 1.0-AF*0.2; |
---|
| 397 | fpz = 1.0+AF*std::max(std::min(pzomc,0.2),-0.2); |
---|
| 398 | }while ((fpzmax*G4UniformRand())>fpz); |
---|
| 399 | |
---|
| 400 | //Energy of the scattered photon |
---|
| 401 | G4double T = pzomc*pzomc; |
---|
| 402 | G4double b1 = 1.0-T*tau*tau; |
---|
| 403 | G4double b2 = 1.0-T*tau*cosTheta; |
---|
| 404 | if (pzomc > 0.0) |
---|
| 405 | epsilon = (tau/b1)*(b2+std::sqrt(std::abs(b2*b2-b1*(1.0-T)))); |
---|
| 406 | else |
---|
| 407 | epsilon = (tau/b1)*(b2-std::sqrt(std::abs(b2*b2-b1*(1.0-T)))); |
---|
| 408 | } //energy < 5 MeV |
---|
| 409 | |
---|
| 410 | //Ok, the kinematics has been calculated. |
---|
| 411 | G4double sinTheta = std::sqrt(1-cosTheta*cosTheta); |
---|
| 412 | G4double phi = twopi * G4UniformRand() ; |
---|
| 413 | G4double dirx = sinTheta * std::cos(phi); |
---|
| 414 | G4double diry = sinTheta * std::sin(phi); |
---|
| 415 | G4double dirz = cosTheta ; |
---|
| 416 | |
---|
| 417 | // Update G4VParticleChange for the scattered photon |
---|
| 418 | G4ThreeVector photonDirection1(dirx,diry,dirz); |
---|
| 419 | photonDirection1.rotateUz(photonDirection0); |
---|
| 420 | fParticleChange->ProposeMomentumDirection(photonDirection1) ; |
---|
| 421 | |
---|
| 422 | G4double photonEnergy1 = epsilon * photonEnergy0; |
---|
| 423 | |
---|
| 424 | if (photonEnergy1 > 0.) |
---|
| 425 | fParticleChange->SetProposedKineticEnergy(photonEnergy1) ; |
---|
| 426 | else |
---|
| 427 | { |
---|
| 428 | fParticleChange->SetProposedKineticEnergy(0.) ; |
---|
| 429 | fParticleChange->ProposeTrackStatus(fStopAndKill); |
---|
| 430 | } |
---|
| 431 | |
---|
| 432 | //Create scattered electron |
---|
| 433 | G4double diffEnergy = photonEnergy0*(1-epsilon); |
---|
| 434 | ionEnergy = (*theTable)[targetOscillator]->GetIonisationEnergy(); |
---|
| 435 | |
---|
| 436 | G4double Q2 = |
---|
| 437 | photonEnergy0*photonEnergy0+photonEnergy1*(photonEnergy1-2.0*photonEnergy0*cosTheta); |
---|
| 438 | G4double cosThetaE = 0.; //scattering angle for the electron |
---|
| 439 | |
---|
| 440 | if (Q2 > 1.0e-12) |
---|
| 441 | cosThetaE = (photonEnergy0-photonEnergy1*cosTheta)/std::sqrt(Q2); |
---|
| 442 | else |
---|
| 443 | cosThetaE = 1.0; |
---|
| 444 | G4double sinThetaE = std::sqrt(1-cosThetaE*cosThetaE); |
---|
| 445 | |
---|
| 446 | //Now, try to handle fluorescence |
---|
| 447 | //Notice: merged levels are indicated with Z=0 and flag=30 |
---|
| 448 | G4int shFlag = (*theTable)[targetOscillator]->GetShellFlag(); |
---|
| 449 | G4int Z = (G4int) (*theTable)[targetOscillator]->GetParentZ(); |
---|
| 450 | |
---|
| 451 | //initialize here, then check photons created by Atomic-Deexcitation, and the final state e- |
---|
| 452 | std::vector<G4DynamicParticle*>* photonVector=0; |
---|
| 453 | const G4AtomicTransitionManager* transitionManager = G4AtomicTransitionManager::Instance(); |
---|
| 454 | G4double bindingEnergy = 0.*eV; |
---|
| 455 | G4int shellId = 0; |
---|
| 456 | |
---|
| 457 | //Real level |
---|
| 458 | if (Z > 0 && shFlag<30) |
---|
| 459 | { |
---|
| 460 | const G4AtomicShell* shell = transitionManager->Shell(Z,shFlag-1); |
---|
| 461 | bindingEnergy = shell->BindingEnergy(); |
---|
| 462 | shellId = shell->ShellId(); |
---|
| 463 | } |
---|
| 464 | |
---|
| 465 | G4double ionEnergyInPenelopeDatabase = ionEnergy; |
---|
| 466 | //protection against energy non-conservation |
---|
| 467 | ionEnergy = std::max(bindingEnergy,ionEnergyInPenelopeDatabase); |
---|
| 468 | |
---|
| 469 | //subtract the excitation energy. If not emitted by fluorescence |
---|
| 470 | //the ionization energy is deposited as local energy deposition |
---|
| 471 | G4double eKineticEnergy = diffEnergy - ionEnergy; |
---|
| 472 | G4double localEnergyDeposit = ionEnergy; |
---|
| 473 | G4double energyInFluorescence = 0.; //testing purposes only |
---|
| 474 | |
---|
| 475 | if (eKineticEnergy < 0) |
---|
| 476 | { |
---|
| 477 | //It means that there was some problem/mismatch between the two databases. |
---|
| 478 | //Try to make it work |
---|
| 479 | //In this case available Energy (diffEnergy) < ionEnergy |
---|
| 480 | //Full residual energy is deposited locally |
---|
| 481 | localEnergyDeposit = diffEnergy; |
---|
| 482 | eKineticEnergy = 0.0; |
---|
| 483 | } |
---|
| 484 | |
---|
| 485 | //the local energy deposit is what remains: part of this may be spent for fluorescence. |
---|
| 486 | if(DeexcitationFlag() && Z > 5) { |
---|
| 487 | |
---|
| 488 | const G4ProductionCutsTable* theCoupleTable= |
---|
| 489 | G4ProductionCutsTable::GetProductionCutsTable(); |
---|
| 490 | |
---|
| 491 | size_t index = couple->GetIndex(); |
---|
| 492 | G4double cutg = (*(theCoupleTable->GetEnergyCutsVector(0)))[index]; |
---|
| 493 | G4double cute = (*(theCoupleTable->GetEnergyCutsVector(1)))[index]; |
---|
| 494 | |
---|
| 495 | // Generation of fluorescence |
---|
| 496 | // Data in EADL are available only for Z > 5 |
---|
| 497 | // Protection to avoid generating photons in the unphysical case of |
---|
| 498 | // shell binding energy > photon energy |
---|
| 499 | if (localEnergyDeposit > cutg || localEnergyDeposit > cute) |
---|
| 500 | { |
---|
| 501 | G4DynamicParticle* aPhoton; |
---|
| 502 | deexcitationManager.SetCutForSecondaryPhotons(cutg); |
---|
| 503 | deexcitationManager.SetCutForAugerElectrons(cute); |
---|
| 504 | |
---|
| 505 | photonVector = deexcitationManager.GenerateParticles(Z,shellId); |
---|
| 506 | if(photonVector) |
---|
| 507 | { |
---|
| 508 | size_t nPhotons = photonVector->size(); |
---|
| 509 | for (size_t k=0; k<nPhotons; k++) |
---|
| 510 | { |
---|
| 511 | aPhoton = (*photonVector)[k]; |
---|
| 512 | if (aPhoton) |
---|
| 513 | { |
---|
| 514 | G4double itsEnergy = aPhoton->GetKineticEnergy(); |
---|
| 515 | if (itsEnergy <= localEnergyDeposit) |
---|
| 516 | { |
---|
| 517 | localEnergyDeposit -= itsEnergy; |
---|
| 518 | if (aPhoton->GetDefinition() == G4Gamma::Gamma()) |
---|
| 519 | energyInFluorescence += itsEnergy;; |
---|
| 520 | fvect->push_back(aPhoton); |
---|
| 521 | } |
---|
| 522 | else |
---|
| 523 | { |
---|
| 524 | delete aPhoton; |
---|
| 525 | (*photonVector)[k]=0; |
---|
| 526 | } |
---|
| 527 | } |
---|
| 528 | } |
---|
| 529 | delete photonVector; |
---|
| 530 | } |
---|
| 531 | } |
---|
| 532 | } |
---|
| 533 | |
---|
| 534 | //Always produce explicitely the electron |
---|
| 535 | G4DynamicParticle* electron = 0; |
---|
| 536 | |
---|
| 537 | G4double xEl = sinThetaE * std::cos(phi+pi); |
---|
| 538 | G4double yEl = sinThetaE * std::sin(phi+pi); |
---|
| 539 | G4double zEl = cosThetaE; |
---|
| 540 | G4ThreeVector eDirection(xEl,yEl,zEl); //electron direction |
---|
| 541 | eDirection.rotateUz(photonDirection0); |
---|
| 542 | electron = new G4DynamicParticle (G4Electron::Electron(), |
---|
| 543 | eDirection,eKineticEnergy) ; |
---|
| 544 | fvect->push_back(electron); |
---|
| 545 | |
---|
| 546 | |
---|
| 547 | if (localEnergyDeposit < 0) |
---|
| 548 | { |
---|
| 549 | G4cout << "WARNING-" |
---|
| 550 | << "G4Penelope08ComptonModel::SampleSecondaries - Negative energy deposit" |
---|
| 551 | << G4endl; |
---|
| 552 | localEnergyDeposit=0.; |
---|
| 553 | } |
---|
| 554 | fParticleChange->ProposeLocalEnergyDeposit(localEnergyDeposit); |
---|
| 555 | |
---|
| 556 | G4double electronEnergy = 0.; |
---|
| 557 | if (verboseLevel > 1) |
---|
| 558 | { |
---|
| 559 | G4cout << "-----------------------------------------------------------" << G4endl; |
---|
| 560 | G4cout << "Energy balance from G4Penelope08Compton" << G4endl; |
---|
| 561 | G4cout << "Incoming photon energy: " << photonEnergy0/keV << " keV" << G4endl; |
---|
| 562 | G4cout << "-----------------------------------------------------------" << G4endl; |
---|
| 563 | G4cout << "Scattered photon: " << photonEnergy1/keV << " keV" << G4endl; |
---|
| 564 | if (electron) |
---|
| 565 | electronEnergy = eKineticEnergy; |
---|
| 566 | G4cout << "Scattered electron " << electronEnergy/keV << " keV" << G4endl; |
---|
| 567 | G4cout << "Fluorescence: " << energyInFluorescence/keV << " keV" << G4endl; |
---|
| 568 | G4cout << "Local energy deposit " << localEnergyDeposit/keV << " keV" << G4endl; |
---|
| 569 | G4cout << "Total final state: " << (photonEnergy1+electronEnergy+energyInFluorescence+ |
---|
| 570 | localEnergyDeposit)/keV << |
---|
| 571 | " keV" << G4endl; |
---|
| 572 | G4cout << "-----------------------------------------------------------" << G4endl; |
---|
| 573 | } |
---|
| 574 | if (verboseLevel > 0) |
---|
| 575 | { |
---|
| 576 | G4double energyDiff = std::fabs(photonEnergy1+ |
---|
| 577 | electronEnergy+energyInFluorescence+ |
---|
| 578 | localEnergyDeposit-photonEnergy0); |
---|
| 579 | if (energyDiff > 0.05*keV) |
---|
| 580 | G4cout << "Warning from G4Penelope08Compton: problem with energy conservation: " << |
---|
| 581 | (photonEnergy1+electronEnergy+energyInFluorescence+localEnergyDeposit)/keV << |
---|
| 582 | " keV (final) vs. " << |
---|
| 583 | photonEnergy0/keV << " keV (initial)" << G4endl; |
---|
| 584 | } |
---|
| 585 | } |
---|
| 586 | |
---|
| 587 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 588 | |
---|
| 589 | G4double G4Penelope08ComptonModel::DifferentialCrossSection(G4double cosTheta,G4double energy, |
---|
| 590 | G4PenelopeOscillator* osc) |
---|
| 591 | { |
---|
| 592 | // |
---|
| 593 | // Penelope model. Single differential cross section *per electron* |
---|
| 594 | // for photon Compton scattering by |
---|
| 595 | // electrons in the given atomic oscillator, differential in the direction of the |
---|
| 596 | // scattering photon. This is in units of pi*classic_electr_radius**2 |
---|
| 597 | // |
---|
| 598 | // D. Brusa et al., Nucl. Instrum. Meth. A 379 (1996) 167 |
---|
| 599 | // The parametrization includes the J(p) distribution profiles for the atomic shells, |
---|
| 600 | // that are tabulated from Hartree-Fock calculations |
---|
| 601 | // from F. Biggs et al., At. Data Nucl. Data Tables 16 (1975) 201 |
---|
| 602 | // |
---|
| 603 | G4double ionEnergy = osc->GetIonisationEnergy(); |
---|
| 604 | G4double harFunc = osc->GetHartreeFactor(); |
---|
| 605 | |
---|
| 606 | const G4double k2 = std::sqrt(2.); |
---|
| 607 | const G4double k1 = 1./k2; |
---|
| 608 | |
---|
| 609 | if (energy < ionEnergy) |
---|
| 610 | return 0; |
---|
| 611 | |
---|
| 612 | //energy of the Compton line |
---|
| 613 | G4double cdt1 = 1.0-cosTheta; |
---|
| 614 | G4double EOEC = 1.0+(energy/electron_mass_c2)*cdt1; |
---|
| 615 | G4double ECOE = 1.0/EOEC; |
---|
| 616 | |
---|
| 617 | //Incoherent scattering function (analytical profile) |
---|
| 618 | G4double aux = energy*(energy-ionEnergy)*cdt1; |
---|
| 619 | G4double Pzimax = |
---|
| 620 | (aux - electron_mass_c2*ionEnergy)/(electron_mass_c2*std::sqrt(2*aux+ionEnergy*ionEnergy)); |
---|
| 621 | G4double sia = 0.0; |
---|
| 622 | G4double x = harFunc*Pzimax; |
---|
| 623 | if (x > 0) |
---|
| 624 | sia = 1.0-0.5*std::exp(0.5-(k1+k2*x)*(k1+k2*x)); |
---|
| 625 | else |
---|
| 626 | sia = 0.5*std::exp(0.5-(k1-k2*x)*(k1-k2*x)); |
---|
| 627 | |
---|
| 628 | //1st order correction, integral of Pz times the Compton profile. |
---|
| 629 | //Calculated approximately using a free-electron gas profile |
---|
| 630 | G4double pf = 3.0/(4.0*harFunc); |
---|
| 631 | if (std::fabs(Pzimax) < pf) |
---|
| 632 | { |
---|
| 633 | G4double QCOE2 = 1.0+ECOE*ECOE-2.0*ECOE*cosTheta; |
---|
| 634 | G4double p2 = Pzimax*Pzimax; |
---|
| 635 | G4double dspz = std::sqrt(QCOE2)* |
---|
| 636 | (1.0+ECOE*(ECOE-cosTheta)/QCOE2)*harFunc |
---|
| 637 | *0.25*(2*p2-(p2*p2)/(pf*pf)-(pf*pf)); |
---|
| 638 | sia += std::max(dspz,-1.0*sia); |
---|
| 639 | } |
---|
| 640 | |
---|
| 641 | G4double XKN = EOEC+ECOE-1.0+cosTheta*cosTheta; |
---|
| 642 | |
---|
| 643 | //Differential cross section (per electron, in units of pi*classic_electr_radius**2) |
---|
| 644 | G4double diffCS = ECOE*ECOE*XKN*sia; |
---|
| 645 | |
---|
| 646 | return diffCS; |
---|
| 647 | } |
---|
| 648 | |
---|
| 649 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 650 | |
---|
| 651 | void G4Penelope08ComptonModel::ActivateAuger(G4bool augerbool) |
---|
| 652 | { |
---|
| 653 | if (!DeexcitationFlag() && augerbool) |
---|
| 654 | { |
---|
| 655 | G4cout << "WARNING - G4Penelope08ComptonModel" << G4endl; |
---|
| 656 | G4cout << "The use of the Atomic Deexcitation Manager is set to false " << G4endl; |
---|
| 657 | G4cout << "Therefore, Auger electrons will be not generated anyway" << G4endl; |
---|
| 658 | } |
---|
| 659 | deexcitationManager.ActivateAugerElectronProduction(augerbool); |
---|
| 660 | if (verboseLevel > 1) |
---|
| 661 | G4cout << "Auger production set to " << augerbool << G4endl; |
---|
| 662 | } |
---|
| 663 | |
---|
| 664 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 665 | |
---|
| 666 | G4double G4Penelope08ComptonModel::OscillatorTotalCrossSection(G4double energy,G4PenelopeOscillator* osc) |
---|
| 667 | { |
---|
| 668 | //Total cross section (integrated) for the given oscillator in units of |
---|
| 669 | //pi*classic_electr_radius^2 |
---|
| 670 | |
---|
| 671 | //Integrate differential cross section for each oscillator |
---|
| 672 | G4double stre = osc->GetOscillatorStrength(); |
---|
| 673 | |
---|
| 674 | // here one uses the using the 20-point |
---|
| 675 | // Gauss quadrature method with an adaptive bipartition scheme |
---|
| 676 | const G4int npoints=10; |
---|
| 677 | const G4int ncallsmax=20000; |
---|
| 678 | const G4int nst=256; |
---|
| 679 | static G4double Abscissas[10] = {7.652651133497334e-02,2.2778585114164508e-01,3.7370608871541956e-01, |
---|
| 680 | 5.1086700195082710e-01,6.3605368072651503e-01,7.4633190646015079e-01, |
---|
| 681 | 8.3911697182221882e-01,9.1223442825132591e-01,9.6397192727791379e-01, |
---|
| 682 | 9.9312859918509492e-01}; |
---|
| 683 | static G4double Weights[10] = {1.5275338713072585e-01,1.4917298647260375e-01,1.4209610931838205e-01, |
---|
| 684 | 1.3168863844917663e-01,1.1819453196151842e-01,1.0193011981724044e-01, |
---|
| 685 | 8.3276741576704749e-02,6.2672048334109064e-02,4.0601429800386941e-02, |
---|
| 686 | 1.7614007139152118e-02}; |
---|
| 687 | |
---|
| 688 | G4double MaxError = 1e-5; |
---|
| 689 | //Error control |
---|
| 690 | G4double Ctol = std::min(std::max(MaxError,1e-13),1e-02); |
---|
| 691 | G4double Ptol = 0.01*Ctol; |
---|
| 692 | G4double Err=1e35; |
---|
| 693 | |
---|
| 694 | //Gauss integration from -1 to 1 |
---|
| 695 | G4double LowPoint = -1.0; |
---|
| 696 | G4double HighPoint = 1.0; |
---|
| 697 | |
---|
| 698 | G4double h=HighPoint-LowPoint; |
---|
| 699 | G4double sumga=0.0; |
---|
| 700 | G4double a=0.5*(HighPoint-LowPoint); |
---|
| 701 | G4double b=0.5*(HighPoint+LowPoint); |
---|
| 702 | G4double c=a*Abscissas[0]; |
---|
| 703 | G4double d= Weights[0]* |
---|
| 704 | (DifferentialCrossSection(b+c,energy,osc)+DifferentialCrossSection(b-c,energy,osc)); |
---|
| 705 | for (G4int i=2;i<=npoints;i++) |
---|
| 706 | { |
---|
| 707 | c=a*Abscissas[i-1]; |
---|
| 708 | d += Weights[i-1]* |
---|
| 709 | (DifferentialCrossSection(b+c,energy,osc)+DifferentialCrossSection(b-c,energy,osc)); |
---|
| 710 | } |
---|
| 711 | G4int icall = 2*npoints; |
---|
| 712 | G4int LH=1; |
---|
| 713 | G4double S[nst],x[nst],sn[nst],xrn[nst]; |
---|
| 714 | S[0]=d*a; |
---|
| 715 | x[0]=LowPoint; |
---|
| 716 | |
---|
| 717 | G4bool loopAgain = true; |
---|
| 718 | |
---|
| 719 | //Adaptive bipartition scheme |
---|
| 720 | do{ |
---|
| 721 | G4double h0=h; |
---|
| 722 | h=0.5*h; //bipartition |
---|
| 723 | G4double sumr=0; |
---|
| 724 | G4int LHN=0; |
---|
| 725 | G4double si,xa,xb,xc; |
---|
| 726 | for (G4int i=1;i<=LH;i++){ |
---|
| 727 | si=S[i-1]; |
---|
| 728 | xa=x[i-1]; |
---|
| 729 | xb=xa+h; |
---|
| 730 | xc=xa+h0; |
---|
| 731 | a=0.5*(xb-xa); |
---|
| 732 | b=0.5*(xb+xa); |
---|
| 733 | c=a*Abscissas[0]; |
---|
| 734 | G4double d = Weights[0]* |
---|
| 735 | (DifferentialCrossSection(b+c,energy,osc)+DifferentialCrossSection(b-c,energy,osc)); |
---|
| 736 | |
---|
| 737 | for (G4int j=1;j<npoints;j++) |
---|
| 738 | { |
---|
| 739 | c=a*Abscissas[j]; |
---|
| 740 | d += Weights[j]* |
---|
| 741 | (DifferentialCrossSection(b+c,energy,osc)+DifferentialCrossSection(b-c,energy,osc)); |
---|
| 742 | } |
---|
| 743 | G4double s1=d*a; |
---|
| 744 | a=0.5*(xc-xb); |
---|
| 745 | b=0.5*(xc+xb); |
---|
| 746 | c=a*Abscissas[0]; |
---|
| 747 | d=Weights[0]* |
---|
| 748 | (DifferentialCrossSection(b+c,energy,osc)+DifferentialCrossSection(b-c,energy,osc)); |
---|
| 749 | |
---|
| 750 | for (G4int j=1;j<npoints;j++) |
---|
| 751 | { |
---|
| 752 | c=a*Abscissas[j]; |
---|
| 753 | d += Weights[j]* |
---|
| 754 | (DifferentialCrossSection(b+c,energy,osc)+DifferentialCrossSection(b-c,energy,osc)); |
---|
| 755 | } |
---|
| 756 | G4double s2=d*a; |
---|
| 757 | icall=icall+4*npoints; |
---|
| 758 | G4double s12=s1+s2; |
---|
| 759 | if (std::abs(s12-si)<std::max(Ptol*std::abs(s12),1e-35)) |
---|
| 760 | sumga += s12; |
---|
| 761 | else |
---|
| 762 | { |
---|
| 763 | sumr += s12; |
---|
| 764 | LHN += 2; |
---|
| 765 | sn[LHN-1]=s2; |
---|
| 766 | xrn[LHN-1]=xb; |
---|
| 767 | sn[LHN-2]=s1; |
---|
| 768 | xrn[LHN-2]=xa; |
---|
| 769 | } |
---|
| 770 | |
---|
| 771 | if (icall>ncallsmax || LHN>nst) |
---|
| 772 | { |
---|
| 773 | G4cout << "G4Penelope08ComptonModel: " << G4endl; |
---|
| 774 | G4cout << "LowPoint: " << LowPoint << ", High Point: " << HighPoint << G4endl; |
---|
| 775 | G4cout << "Tolerance: " << MaxError << G4endl; |
---|
| 776 | G4cout << "Calls: " << icall << ", Integral: " << sumga << ", Error: " << Err << G4endl; |
---|
| 777 | G4cout << "Number of open subintervals: " << LHN << G4endl; |
---|
| 778 | G4cout << "WARNING: the required accuracy has not been attained" << G4endl; |
---|
| 779 | loopAgain = false; |
---|
| 780 | } |
---|
| 781 | } |
---|
| 782 | Err=std::abs(sumr)/std::max(std::abs(sumr+sumga),1e-35); |
---|
| 783 | if (Err < Ctol || LHN == 0) |
---|
| 784 | loopAgain = false; //end of cycle |
---|
| 785 | LH=LHN; |
---|
| 786 | for (G4int i=0;i<LH;i++) |
---|
| 787 | { |
---|
| 788 | S[i]=sn[i]; |
---|
| 789 | x[i]=xrn[i]; |
---|
| 790 | } |
---|
| 791 | }while(Ctol < 1.0 && loopAgain); |
---|
| 792 | |
---|
| 793 | |
---|
| 794 | G4double xs = stre*sumga; |
---|
| 795 | |
---|
| 796 | return xs; |
---|
| 797 | } |
---|
| 798 | |
---|
| 799 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
| 800 | |
---|
| 801 | G4double G4Penelope08ComptonModel::KleinNishinaCrossSection(G4double energy, |
---|
| 802 | const G4Material* material) |
---|
| 803 | { |
---|
| 804 | // use Klein-Nishina formula |
---|
| 805 | // total cross section in units of pi*classic_electr_radius^2 |
---|
| 806 | |
---|
| 807 | G4double cs = 0; |
---|
| 808 | |
---|
| 809 | G4double ek =energy/electron_mass_c2; |
---|
| 810 | G4double eks = ek*ek; |
---|
| 811 | G4double ek2 = 1.0+ek+ek; |
---|
| 812 | G4double ek1 = eks-ek2-1.0; |
---|
| 813 | |
---|
| 814 | G4double t0 = 1.0/ek2; |
---|
| 815 | G4double csl = 0.5*eks*t0*t0+ek2*t0+ek1*std::log(t0)-(1.0/t0); |
---|
| 816 | |
---|
| 817 | G4PenelopeOscillatorTable* theTable = oscManager->GetOscillatorTableCompton(material); |
---|
| 818 | |
---|
| 819 | for (size_t i=0;i<theTable->size();i++) |
---|
| 820 | { |
---|
| 821 | G4PenelopeOscillator* theOsc = (*theTable)[i]; |
---|
| 822 | G4double ionEnergy = theOsc->GetIonisationEnergy(); |
---|
| 823 | G4double tau=(energy-ionEnergy)/energy; |
---|
| 824 | if (tau > t0) |
---|
| 825 | { |
---|
| 826 | G4double csu = 0.5*eks*tau*tau+ek2*tau+ek1*std::log(tau)-(1.0/tau); |
---|
| 827 | G4double stre = theOsc->GetOscillatorStrength(); |
---|
| 828 | |
---|
| 829 | cs += stre*(csu-csl); |
---|
| 830 | } |
---|
| 831 | } |
---|
| 832 | |
---|
| 833 | cs /= (ek*eks); |
---|
| 834 | |
---|
| 835 | return cs; |
---|
| 836 | |
---|
| 837 | } |
---|
| 838 | |
---|