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Novak) << 43 // 40 // 44 // Class Description: 41 // Class Description: 45 // 42 // 46 // Implementation of gamma conversion to e+e- << 43 // Implementation of gamma convertion to e+e- in the field of a nucleus 47 // relativistic approximation 44 // relativistic approximation 48 // 45 // 49 46 50 // ------------------------------------------- 47 // ------------------------------------------------------------------- 51 // 48 // 52 49 53 #ifndef G4PairProductionRelModel_h 50 #ifndef G4PairProductionRelModel_h 54 #define G4PairProductionRelModel_h 1 51 #define G4PairProductionRelModel_h 1 55 52 56 #include <CLHEP/Units/PhysicalConstants.h> 53 #include <CLHEP/Units/PhysicalConstants.h> 57 54 58 #include "G4VEmModel.hh" 55 #include "G4VEmModel.hh" 59 #include "G4Log.hh" << 56 #include "G4PhysicsTable.hh" 60 #include <vector> << 57 #include "G4NistManager.hh" 61 58 62 class G4ParticleChangeForGamma; 59 class G4ParticleChangeForGamma; 63 class G4Pow; << 64 60 65 class G4PairProductionRelModel : public G4VEmM 61 class G4PairProductionRelModel : public G4VEmModel 66 { 62 { 67 63 68 public: 64 public: 69 65 70 explicit G4PairProductionRelModel(const G4Pa << 66 G4PairProductionRelModel(const G4ParticleDefinition* p = 0, 71 const G4St << 67 const G4String& nam = "BetheHeitlerLPM"); 72 68 73 ~G4PairProductionRelModel() override; << 69 virtual ~G4PairProductionRelModel(); 74 70 75 void Initialise(const G4ParticleDefinition*, << 71 virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&); 76 72 77 void InitialiseLocal(const G4ParticleDefinit << 73 virtual void InitialiseLocal(const G4ParticleDefinition*, 78 G4VEmModel* masterModel) override; << 74 G4VEmModel* masterModel); 79 75 80 G4double ComputeCrossSectionPerAtom(const G4 << 76 virtual G4double ComputeCrossSectionPerAtom( 81 G4double kinEnergy, << 77 const G4ParticleDefinition*, 82 G4double Z, << 78 G4double kinEnergy, 83 G4double A=0., << 79 G4double Z, 84 G4double cut=0., << 80 G4double A=0., 85 G4double emax=DBL_MAX) override; << 81 G4double cut=0., 86 << 82 G4double emax=DBL_MAX); 87 void SampleSecondaries(std::vector<G4Dynamic << 83 88 const G4MaterialCutsCouple*, << 84 virtual void SampleSecondaries(std::vector<G4DynamicParticle*>*, 89 const G4DynamicParticle*, << 85 const G4MaterialCutsCouple*, 90 G4double tmin, << 86 const G4DynamicParticle*, 91 G4double maxEnergy) override; << 87 G4double tmin, 92 << 88 G4double maxEnergy); 93 void SetupForMaterial(const G4ParticleDefini << 89 94 const G4Material*,G4double) override; << 90 virtual void SetupForMaterial(const G4ParticleDefinition*, 95 << 91 const G4Material*,G4double); 96 inline void SetLPMflag(G4bool val) { fIsUs << 92 97 inline G4bool LPMflag() const { retur << 93 // * fast inline functions * 98 << 94 inline void SetCurrentElement(G4double /*Z*/); 99 G4PairProductionRelModel & operator= << 95 100 (const G4PairProductionRelModel &right) = de << 96 // set / get methods 101 G4PairProductionRelModel(const G4PairProduc << 97 inline void SetLPMconstant(G4double val); >> 98 inline G4double LPMconstant() const; >> 99 >> 100 inline void SetLPMflag(G4bool); >> 101 inline G4bool LPMflag() const; 102 102 103 protected: 103 protected: 104 104 105 // for evaluating screening related function << 105 // screening functions 106 inline void ComputePhi12(const G4double delt << 106 inline G4double Phi1(G4double delta) const; 107 G4double &phi1, G4double &phi2); << 107 inline G4double Phi2(G4double delta) const; 108 inline G4double ScreenFunction1(const G4doub << 108 inline G4double ScreenFunction1(G4double ScreenVariable); 109 inline G4double ScreenFunction2(const G4doub << 109 inline G4double ScreenFunction2(G4double ScreenVariable); 110 inline void ScreenFunction12(const G4double << 110 inline G4double DeltaMax() const; 111 G4double &f1, G4double &f2); << 111 inline G4double DeltaMin(G4double) const; 112 // helper methods for cross-section computat << 112 113 G4double ComputeParametrizedXSectionPerAtom( << 113 // lpm functions 114 G4double ComputeXSectionPerAtom(G4double gam << 114 void CalcLPMFunctions(G4double k, G4double eplus); 115 G4double ComputeDXSectionPerAtom(G4double ep << 115 116 G4double Z) << 116 G4double ComputeXSectionPerAtom(G4double totalEnergy, G4double Z); 117 G4double ComputeRelDXSectionPerAtom(G4double << 117 118 G4double gammaEnergy, G4double Z << 118 G4double ComputeDXSectionPerAtom(G4double eplusEnergy, G4double totalEnergy, G4double Z); 119 << 119 G4double ComputeRelDXSectionPerAtom(G4double eplusEnergy, G4double totalEnergy, G4double Z); 120 private: << 120 121 << 121 // hide assignment operator 122 // for creating some data structure per Z << 122 G4PairProductionRelModel & operator=(const G4PairProductionRelModel &right); 123 void InitialiseElementData(); << 123 G4PairProductionRelModel(const G4PairProductionRelModel&); 124 struct ElementData { << 124 125 G4double fLogZ13; << 125 G4NistManager* nist; 126 G4double fCoulomb; << 126 127 G4double fLradEl; << 127 G4ParticleDefinition* theGamma; 128 G4double fDeltaFactor; << 128 G4ParticleDefinition* theElectron; 129 G4double fDeltaMaxLow; << 129 G4ParticleDefinition* thePositron; 130 G4double fDeltaMaxHigh; << 130 G4ParticleChangeForGamma* fParticleChange; 131 G4double fEtaValue; << 131 132 G4double fLPMVarS1Cond; << 132 G4double fLPMconstant; 133 G4double fLPMILVarS1Cond; << 133 G4bool fLPMflag; 134 }; << 134 135 // for precomputing comp. intensive parts of << 135 // cash 136 // using them at run-time << 136 G4double z13, z23, lnZ; 137 void InitLPMFunctions(); << 137 G4double Fel, Finel, fCoulomb; 138 void ComputeLPMGsPhis(G4double &funcGS, G4do << 138 G4double currentZ; 139 const G4double varShat << 139 140 void GetLPMFunctions(G4double &lpmGs, G4doub << 140 // LPM effect 141 void ComputeLPMfunctions(G4double &fXiS, G4d << 141 G4double lpmEnergy; 142 const G4double eps, << 142 G4double xiLPM, phiLPM, gLPM; 143 const G4int izet); << 143 144 struct LPMFuncs { << 144 // consts 145 LPMFuncs() : fIsInitialized(false), fISDel << 145 G4bool use_completescreening; 146 G4bool fIsInitialized; << 146 147 G4double fISDelta; << 147 static const G4double xgi[8], wgi[8]; 148 G4double fSLimit; << 148 static const G4double Fel_light[5]; 149 std::vector<G4double> fLPMFuncG; << 149 static const G4double Finel_light[5]; 150 std::vector<G4double> fLPMFuncPhi; << 150 static const G4double facFel; 151 }; << 151 static const G4double facFinel; >> 152 >> 153 static const G4double preS1, logTwo; 152 154 153 protected: << 154 static const G4int gMaxZet; << 155 // << 156 static const G4double gLPMconsta << 157 // << 158 static const G4double gXGL[8]; << 159 static const G4double gWGL[8]; << 160 static const G4double gFelLowZet << 161 static const G4double gFinelLowZ << 162 // << 163 static const G4double gXSecFacto << 164 static const G4double gEgLPMActi << 165 // << 166 static std::vector<ElementData*> gElementDa << 167 static LPMFuncs gLPMFuncs; << 168 // << 169 G4bool isFirstInstance{false}; << 170 G4bool fIsUseLPMC << 171 G4bool fIsUseComp << 172 // << 173 G4double fLPMEnergy << 174 // << 175 G4double fParametri << 176 G4double fCoulombCo << 177 // << 178 G4Pow* fG4Calc; << 179 G4ParticleDefinition* fTheGamma; << 180 G4ParticleDefinition* fTheElectr << 181 G4ParticleDefinition* fThePositr << 182 G4ParticleChangeForGamma* fParticleC << 183 }; 155 }; 184 // << 156 185 // Bethe screening functions for the elastic ( << 157 186 // Bethe's phi1, phi2 coherent screening funct << 158 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... 187 // by using (the universal) atomic form factor << 159 188 // Fermi model of the atom (using numerical so << 160 inline 189 // screening function instead of Moliere's ana << 161 void G4PairProductionRelModel::SetLPMconstant(G4double val) 190 // numerical results can be well approximated << 162 { 191 // especially near the delta=1 limit) by: << 163 fLPMconstant = val; 192 // ## if delta <= 1.4 << 193 // phi1(delta) = 20.806 - delta*(3.190 - 0.57 << 194 // phi2(delta) = 20.234 - delta*(2.126 - 0.09 << 195 // ## if delta > 1.4 << 196 // phi1(delta) = phi2(delta) = 21.0190 - 4.14 << 197 // with delta = 136mc^2kZ^{-1/3}/[E(Eg-E)] = 1 << 198 // Eg is the initial photon energy, E is the t << 199 // the e-/e+ pair, eps0 = mc^2/Eg and eps = E/ << 200 << 201 inline void G4PairProductionRelModel::ComputeP << 202 G4double &phi1, << 203 G4double &phi2) << 204 { << 205 if (delta > 1.4) { << 206 phi1 = 21.0190 - 4.145*G4Log(delta + 0.9 << 207 phi2 = phi1; << 208 } else { << 209 phi1 = 20.806 - delta*(3.190 - 0.5710*de << 210 phi2 = 20.234 - delta*(2.126 - 0.0903*de << 211 } << 212 } 164 } 213 165 214 // Compute the value of the screening function << 166 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... 215 inline G4double G4PairProductionRelModel::Scre << 167 >> 168 inline >> 169 G4double G4PairProductionRelModel::LPMconstant() const >> 170 { >> 171 return fLPMconstant; >> 172 } >> 173 >> 174 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... >> 175 >> 176 inline >> 177 void G4PairProductionRelModel::SetLPMflag(G4bool val) 216 { 178 { 217 return (delta > 1.4) ? 42.038 - 8.29*G4Log(d << 179 fLPMflag = val; 218 : 42.184 - delta*(7.444 << 219 } 180 } 220 181 221 // Compute the value of the screening function << 182 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... 222 inline G4double G4PairProductionRelModel::Scre << 183 >> 184 inline >> 185 G4bool G4PairProductionRelModel::LPMflag() const 223 { 186 { 224 return (delta > 1.4) ? 42.038 - 8.29*G4Log(d << 187 return fLPMflag; 225 : 41.326 - delta*(5.848 << 226 } 188 } 227 189 228 // Same as ScreenFunction1 and ScreenFunction2 << 190 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... 229 inline void G4PairProductionRelModel::ScreenFu << 191 230 << 192 inline void G4PairProductionRelModel::SetCurrentElement(G4double Z) 231 { 193 { 232 if (delta > 1.4) { << 194 if(Z != currentZ) { 233 f1 = 42.038 - 8.29*G4Log(delta + 0.958); << 195 currentZ = Z; 234 f2 = f1; << 196 235 } else { << 197 G4int iz = G4int(Z); 236 f1 = 42.184 - delta*(7.444 - 1.623*delta); << 198 z13 = nist->GetZ13(iz); 237 f2 = 41.326 - delta*(5.848 - 0.902*delta); << 199 z23 = z13*z13; >> 200 lnZ = nist->GetLOGZ(iz); >> 201 >> 202 if (iz <= 4) { >> 203 Fel = Fel_light[iz]; >> 204 Finel = Finel_light[iz] ; >> 205 } >> 206 else { >> 207 Fel = facFel - lnZ/3. ; >> 208 Finel = facFinel - 2.*lnZ/3. ; >> 209 } >> 210 fCoulomb=GetCurrentElement()->GetfCoulomb(); 238 } 211 } 239 } 212 } >> 213 >> 214 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... >> 215 >> 216 inline G4double G4PairProductionRelModel::Phi1(G4double delta) const >> 217 { >> 218 G4double screenVal; >> 219 >> 220 if (delta > 1.) >> 221 screenVal = 21.12 - 4.184*std::log(delta+0.952); >> 222 else >> 223 screenVal = 20.868 - delta*(3.242 - 0.625*delta); >> 224 >> 225 return screenVal; >> 226 } >> 227 >> 228 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... >> 229 >> 230 inline G4double G4PairProductionRelModel::Phi2(G4double delta) const >> 231 { >> 232 G4double screenVal; >> 233 >> 234 if (delta > 1.) >> 235 screenVal = 21.12 - 4.184*std::log(delta+0.952); >> 236 else >> 237 screenVal = 20.209 - delta*(1.930 + 0.086*delta); >> 238 >> 239 return screenVal; >> 240 } >> 241 >> 242 inline G4double G4PairProductionRelModel::ScreenFunction1(G4double ScreenVariable) >> 243 >> 244 // compute the value of the screening function 3*PHI1 - PHI2 >> 245 >> 246 { >> 247 G4double screenVal; >> 248 >> 249 if (ScreenVariable > 1.) >> 250 screenVal = 42.24 - 8.368*std::log(ScreenVariable+0.952); >> 251 else >> 252 screenVal = 42.392 - ScreenVariable*(7.796 - 1.961*ScreenVariable); >> 253 >> 254 return screenVal; >> 255 } >> 256 >> 257 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... >> 258 >> 259 inline G4double G4PairProductionRelModel::ScreenFunction2(G4double ScreenVariable) >> 260 >> 261 // compute the value of the screening function 1.5*PHI1 + 0.5*PHI2 >> 262 >> 263 { >> 264 G4double screenVal; >> 265 >> 266 if (ScreenVariable > 1.) >> 267 screenVal = 42.24 - 8.368*std::log(ScreenVariable+0.952); >> 268 else >> 269 screenVal = 41.405 - ScreenVariable*(5.828 - 0.8945*ScreenVariable); >> 270 >> 271 return screenVal; >> 272 } >> 273 >> 274 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... >> 275 >> 276 >> 277 inline G4double G4PairProductionRelModel::DeltaMax() const >> 278 { >> 279 // k > 50 MeV >> 280 G4double FZ = 8.*(lnZ/3. + fCoulomb); >> 281 return std::exp( (42.24-FZ)/8.368 ) + 0.952; >> 282 } >> 283 >> 284 inline G4double G4PairProductionRelModel::DeltaMin(G4double k) const >> 285 { >> 286 return 4.*136./z13*(CLHEP::electron_mass_c2/k); >> 287 } >> 288 >> 289 240 290 241 #endif 291 #endif 242 292