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24 | // ******************************************************************** |
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25 | // |
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26 | // $Id: G4ElectroNuclearReaction.hh,v 1.27 2009/02/23 09:49:24 mkossov Exp $ |
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27 | // GEANT4 tag $Name: hadr-chips-V09-03-08 $ |
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28 | // |
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29 | // GEANT4 physics class: G4ElectroNuclearReaction -- header file for CHIPS |
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30 | // Created: J.P. Wellisch, following M. Kossov's algorithm. 12/11/2001 |
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31 | // The last update: J.P. Wellisch, 06-June-02 |
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32 | // 17.02.2009 M.Kossov, now it is recommended to use the G4QCollision process |
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33 | // |
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34 | #ifndef G4ElectroNuclearReaction_h |
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35 | #define G4ElectroNuclearReaction_h 1 |
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36 | |
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37 | #include "globals.hh" |
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38 | #include "G4HadronicInteraction.hh" |
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39 | #include "G4ChiralInvariantPhaseSpace.hh" |
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40 | #include "G4ElectroNuclearCrossSection.hh" |
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41 | #include "G4PhotoNuclearCrossSection.hh" |
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42 | #include "G4GammaParticipants.hh" |
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43 | #include "G4QGSModel.hh" |
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44 | #include "G4QGSMFragmentation.hh" |
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45 | #include "G4Nucleus.hh" |
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46 | #include "G4HadFinalState.hh" |
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47 | #include "G4HadProjectile.hh" |
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48 | #include "G4Electron.hh" |
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49 | #include "G4Positron.hh" |
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50 | #include "G4Gamma.hh" |
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51 | #include "G4TheoFSGenerator.hh" |
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52 | #include "G4GeneratorPrecompoundInterface.hh" |
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53 | #include "G4ExcitedStringDecay.hh" |
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54 | |
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55 | class G4ElectroNuclearReaction : public G4HadronicInteraction |
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56 | { |
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57 | public: |
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58 | |
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59 | G4ElectroNuclearReaction():G4HadronicInteraction("CHIPS") |
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60 | { |
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61 | SetMinEnergy(0*GeV); |
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62 | SetMaxEnergy(30*TeV); |
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63 | |
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64 | theHEModel = new G4TheoFSGenerator; |
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65 | theCascade = new G4GeneratorPrecompoundInterface; |
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66 | theHEModel->SetTransport(theCascade); |
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67 | theHEModel->SetHighEnergyGenerator(&theStringModel); |
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68 | theStringDecay = new G4ExcitedStringDecay(&theFragmentation); |
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69 | theStringModel.SetFragmentationModel(theStringDecay); |
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70 | theHEModel->SetMinEnergy(2.5*GeV); |
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71 | theHEModel->SetMaxEnergy(100*TeV); |
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72 | } |
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73 | |
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74 | virtual ~G4ElectroNuclearReaction() {delete theStringDecay;}; |
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75 | |
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76 | G4HadFinalState* ApplyYourself(const G4HadProjectile& aTrack, |
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77 | G4Nucleus& aTargetNucleus); |
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78 | |
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79 | private: |
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80 | |
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81 | G4ChiralInvariantPhaseSpace theLEModel; |
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82 | G4TheoFSGenerator * theHEModel; |
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83 | G4GeneratorPrecompoundInterface * theCascade; |
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84 | G4QGSModel< G4GammaParticipants > theStringModel; |
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85 | G4QGSMFragmentation theFragmentation; |
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86 | G4ExcitedStringDecay * theStringDecay; |
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87 | G4ElectroNuclearCrossSection theElectronData; |
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88 | G4PhotoNuclearCrossSection thePhotonData; |
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89 | G4HadFinalState theResult; |
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90 | }; |
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91 | |
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92 | inline |
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93 | G4HadFinalState* G4ElectroNuclearReaction::ApplyYourself(const G4HadProjectile& aTrack, |
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94 | G4Nucleus& aTargetNucleus) |
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95 | { |
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96 | theResult.Clear(); |
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97 | static const G4double dM=G4Proton::Proton()->GetPDGMass()+ |
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98 | G4Neutron::Neutron()->GetPDGMass(); // MeanDoubleNucleon Mass = m_n+m_p (@@ no binding) |
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99 | static const G4double me=G4Electron::Electron()->GetPDGMass(); // electron mass |
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100 | static const G4double me2=me*me; // squared electron mass |
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101 | G4DynamicParticle theTempEl(const_cast<G4ParticleDefinition *>(aTrack.GetDefinition()), |
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102 | aTrack.Get4Momentum().vect()); |
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103 | const G4DynamicParticle* theElectron=&theTempEl; |
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104 | const G4ParticleDefinition* aD = theElectron->GetDefinition(); |
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105 | if((aD != G4Electron::ElectronDefinition()) && (aD != G4Positron::PositronDefinition())) |
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106 | throw G4HadronicException(__FILE__, __LINE__, |
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107 | "G4ElectroNuclearReaction::ApplyYourself called for neither electron or positron"); |
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108 | const G4ElementTable* aTab = G4Element::GetElementTable(); |
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109 | G4Element * anElement = 0; |
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110 | G4int aZ = static_cast<G4int>(aTargetNucleus.GetZ()+.1); |
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111 | for(size_t ii=0; ii<aTab->size(); ii++) |
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112 | { |
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113 | if ( std::abs((*aTab)[ii]->GetZ()-aZ) < .1) |
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114 | { |
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115 | anElement = (*aTab)[ii]; |
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116 | break; |
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117 | } |
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118 | } |
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119 | if(0==anElement) |
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120 | { |
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121 | G4cerr<<"***G4ElectroNuclearReaction::ApplyYourself: element with Z=" |
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122 | <<aTargetNucleus.GetZ()<<" is not in the element table"<<G4endl; |
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123 | throw G4HadronicException(__FILE__, __LINE__, "Anomalous element error."); |
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124 | } |
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125 | |
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126 | // Note: high energy gamma nuclear now implemented. |
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127 | G4double xSec = theElectronData.GetCrossSection(theElectron, anElement);// Check XSection |
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128 | if(xSec<=0.) |
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129 | { |
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130 | theResult.SetStatusChange(isAlive); |
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131 | theResult.SetEnergyChange(theElectron->GetKineticEnergy()); |
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132 | // new direction for the electron |
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133 | theResult.SetMomentumChange(theElectron->GetMomentumDirection()); |
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134 | return &theResult; // DO-NOTHING condition |
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135 | } |
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136 | G4double photonEnergy = theElectronData.GetEquivalentPhotonEnergy(); |
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137 | G4double theElectronKinEnergy=theElectron->GetKineticEnergy(); |
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138 | if( theElectronKinEnergy < photonEnergy ) |
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139 | { |
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140 | G4cout<<"G4ElectroNuclearReaction::ApplyYourself: photonEnergy is very high"<<G4endl; |
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141 | G4cout<<">>> If this condition persists, please contact Geant4 group"<<G4endl; |
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142 | theResult.SetStatusChange(isAlive); |
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143 | theResult.SetEnergyChange(theElectron->GetKineticEnergy()); |
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144 | // new direction for the electron |
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145 | theResult.SetMomentumChange(theElectron->GetMomentumDirection()); |
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146 | return &theResult; // DO-NOTHING condition |
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147 | } |
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148 | G4double photonQ2 = theElectronData.GetEquivalentPhotonQ2(photonEnergy); |
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149 | G4double W=photonEnergy-photonQ2/dM; // Hadronic energy flow from the virtual photon |
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150 | if(getenv("debug_G4ElectroNuclearReaction") ) |
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151 | { |
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152 | G4cout << "G4ElectroNuclearReaction: Equivalent Energy = "<<W<<G4endl; |
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153 | } |
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154 | if(W<0.) |
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155 | { |
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156 | theResult.SetStatusChange(isAlive); |
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157 | theResult.SetEnergyChange(theElectron->GetKineticEnergy()); |
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158 | // new direction for the electron |
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159 | theResult.SetMomentumChange(theElectron->GetMomentumDirection()); |
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160 | return &theResult; // DO-NOTHING condition |
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161 | throw G4HadronicException(__FILE__, __LINE__, |
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162 | "G4ElectroNuclearReaction::ApplyYourself: negative equivalent energy"); |
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163 | } |
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164 | G4DynamicParticle* theDynamicPhoton = new |
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165 | G4DynamicParticle(G4Gamma::GammaDefinition(), |
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166 | G4ParticleMomentum(1.,0.,0.), photonEnergy*MeV); //----->-* |
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167 | G4double sigNu=thePhotonData.GetCrossSection(theDynamicPhoton, anElement); // | |
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168 | theDynamicPhoton->SetKineticEnergy(W); // Redefine photon with equivalent energy | |
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169 | G4double sigK =thePhotonData.GetCrossSection(theDynamicPhoton, anElement); // | |
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170 | delete theDynamicPhoton; // <-------------------------------------------------------* |
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171 | G4double rndFraction = theElectronData.GetVirtualFactor(photonEnergy, photonQ2); |
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172 | if(sigNu*G4UniformRand()>sigK*rndFraction) |
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173 | { |
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174 | theResult.SetStatusChange(isAlive); |
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175 | theResult.SetEnergyChange(theElectron->GetKineticEnergy()); |
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176 | // new direction for the electron |
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177 | theResult.SetMomentumChange(theElectron->GetMomentumDirection()); |
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178 | return &theResult; // DO-NOTHING condition |
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179 | } |
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180 | theResult.SetStatusChange(isAlive); |
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181 | // Scatter an electron and make gamma+A reaction |
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182 | G4double iniE=theElectronKinEnergy+me; // Initial total energy of electron |
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183 | G4double finE=iniE-photonEnergy; // Final total energy of electron |
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184 | theResult.SetEnergyChange(std::max(0.,finE-me)); // Modifies the KINETIC ENERGY |
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185 | G4double EEm=iniE*finE-me2; // Just an intermediate value to avoid "2*" |
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186 | G4double iniP=std::sqrt(iniE*iniE-me2); // Initial momentum of the electron |
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187 | G4double finP=std::sqrt(finE*finE-me2); // Final momentum of the electron |
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188 | G4double cost=(EEm+EEm-photonQ2)/iniP/finP;// std::cos(theta) for the electron scattering |
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189 | if(cost>1.) cost=1.; |
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190 | if(cost<-1.) cost=-1.; |
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191 | G4ThreeVector dir=theElectron->GetMomentumDirection(); // Direction of primary electron |
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192 | G4ThreeVector ort=dir.orthogonal(); // Not normed orthogonal vector (!) (to dir) |
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193 | G4ThreeVector ortx = ort.unit(); // First unit vector orthogonal to the direction |
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194 | G4ThreeVector orty = dir.cross(ortx); // Second unit vector orthoganal to the direction |
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195 | G4double sint=std::sqrt(1.-cost*cost); // Perpendicular component |
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196 | G4double phi=twopi*G4UniformRand(); // phi of scattered electron |
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197 | G4double sinx=sint*std::sin(phi); // x-component |
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198 | G4double siny=sint*std::cos(phi); // y-component |
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199 | G4ThreeVector findir=cost*dir+sinx*ortx+siny*orty; |
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200 | theResult.SetMomentumChange(findir); // new direction for the electron |
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201 | G4ThreeVector photonMomentum=iniP*dir-finP*findir; |
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202 | G4DynamicParticle localGamma(G4Gamma::GammaDefinition(), photonEnergy, photonMomentum); |
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203 | //G4DynamicParticle localGamma(G4Gamma::GammaDefinition(),photonDirection, photonEnergy); |
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204 | //G4DynamicParticle localGamma(G4Gamma::GammaDefinition(), photonLorentzVector); |
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205 | G4ThreeVector position(0,0,0); |
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206 | G4HadProjectile localTrack(localGamma); |
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207 | G4HadFinalState * result; |
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208 | if(photonEnergy < 3*GeV) |
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209 | { |
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210 | result = theLEModel.ApplyYourself(localTrack, aTargetNucleus, &theResult); |
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211 | } |
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212 | else |
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213 | { |
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214 | // G4cout << "0) Getting a high energy electro-nuclear reaction"<<G4endl; |
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215 | G4HadFinalState * aResult = theHEModel->ApplyYourself(localTrack, aTargetNucleus); |
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216 | for(G4int all = 0; all < aResult->GetNumberOfSecondaries(); all++) |
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217 | { |
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218 | theResult.AddSecondary(aResult->GetSecondary(all)); |
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219 | } |
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220 | aResult->SecondariesAreStale(); |
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221 | result = &theResult; |
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222 | } |
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223 | return result; |
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224 | } |
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225 | |
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226 | #endif |
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