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25 | // |
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26 | // |
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27 | // |
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28 | // $Id: G4ElectroNuclearReaction.hh,v 1.23 2006/06/29 20:07:46 gunter Exp $ |
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29 | // GEANT4 tag $Name: $ |
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30 | // |
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31 | // |
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32 | // GEANT4 physics class: G4ElectroNuclearReaction -- header file |
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33 | // Created: J.P. Wellisch, 12/11/2001 |
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34 | // The last update: J.P. Wellisch, 06-June-02 |
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35 | // |
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36 | #ifndef G4ElectroNuclearReaction_h |
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37 | #define G4ElectroNuclearReaction_h |
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38 | |
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39 | #include "globals.hh" |
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40 | #include "G4HadronicInteraction.hh" |
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41 | #include "G4ChiralInvariantPhaseSpace.hh" |
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42 | #include "G4ElectroNuclearCrossSection.hh" |
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43 | #include "G4PhotoNuclearCrossSection.hh" |
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44 | #include "G4Electron.hh" |
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45 | #include "G4Positron.hh" |
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46 | #include "G4Gamma.hh" |
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47 | #include "G4GammaParticipants.hh" |
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48 | #include "G4QGSModel.hh" |
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49 | #include "G4TheoFSGenerator.hh" |
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50 | #include "G4GeneratorPrecompoundInterface.hh" |
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51 | #include "G4QGSMFragmentation.hh" |
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52 | #include "G4ExcitedStringDecay.hh" |
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53 | |
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54 | class G4ElectroNuclearReaction : public G4HadronicInteraction |
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55 | { |
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56 | public: |
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57 | virtual ~G4ElectroNuclearReaction(){} |
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58 | G4ElectroNuclearReaction() |
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59 | { |
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60 | SetMinEnergy(0*GeV); |
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61 | SetMaxEnergy(30*TeV); |
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62 | |
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63 | theHEModel = new G4TheoFSGenerator; |
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64 | theCascade = new G4GeneratorPrecompoundInterface; |
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65 | } |
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66 | |
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67 | virtual G4HadFinalState* ApplyYourself(const G4HadProjectile& aTrack, |
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68 | G4Nucleus& aTargetNucleus); |
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69 | |
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70 | private: |
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71 | G4ChiralInvariantPhaseSpace theLEModel; |
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72 | G4TheoFSGenerator * theHEModel; |
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73 | G4GeneratorPrecompoundInterface * theCascade; |
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74 | G4QGSModel< G4GammaParticipants > theStringModel; |
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75 | G4QGSMFragmentation theFragmentation; |
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76 | G4ExcitedStringDecay * theStringDecay; |
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77 | G4ElectroNuclearCrossSection theElectronData; |
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78 | G4PhotoNuclearCrossSection thePhotonData; |
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79 | G4HadFinalState theResult; |
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80 | }; |
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81 | |
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82 | inline G4HadFinalState* G4ElectroNuclearReaction:: |
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83 | ApplyYourself(const G4HadProjectile& aTrack, G4Nucleus& aTargetNucleus) |
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84 | { |
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85 | theResult.Clear(); |
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86 | static const G4double dM=G4Proton::Proton()->GetPDGMass()+G4Neutron::Neutron()->GetPDGMass(); // Mean double nucleon mass = m_n+m_p (@@ no binding) |
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87 | static const G4double me=G4Electron::Electron()->GetPDGMass(); // electron mass |
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88 | static const G4double me2=me*me; // squared electron mass |
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89 | static const G4double dpi=twopi; // 2*pi |
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90 | G4DynamicParticle theTempEl(const_cast<G4ParticleDefinition *>(aTrack.GetDefinition()), |
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91 | aTrack.Get4Momentum().vect()); |
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92 | const G4DynamicParticle* theElectron=&theTempEl; |
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93 | const G4ParticleDefinition* aD = theElectron->GetDefinition(); |
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94 | if((aD != G4Electron::ElectronDefinition()) && (aD != G4Positron::PositronDefinition())) |
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95 | throw G4HadronicException(__FILE__, __LINE__, "G4ElectroNuclearReaction::ApplyYourself called for neither electron or positron"); |
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96 | |
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97 | const G4ElementTable* aTab = G4Element::GetElementTable(); |
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98 | G4Element * anElement = 0; |
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99 | G4int aZ = static_cast<G4int>(aTargetNucleus.GetZ()+.1); |
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100 | for(size_t ii=0; ii<aTab->size(); ii++) |
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101 | { |
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102 | if ( std::abs((*aTab)[ii]->GetZ()-aZ) < .1) |
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103 | { |
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104 | anElement = (*aTab)[ii]; |
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105 | break; |
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106 | } |
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107 | } |
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108 | if(0==anElement) |
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109 | { |
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110 | G4cerr<<"***G4ElectroNuclearReaction::ApplyYourself: element with Z="<<aTargetNucleus.GetZ()<< |
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111 | " is not in the element table"<<G4endl; // @@ how to retrieve A or N for the isotop? |
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112 | throw G4HadronicException(__FILE__, __LINE__, "Anomalous element error."); |
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113 | } |
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114 | |
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115 | // Note: high energy gamma nuclear now implemented. |
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116 | |
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117 | G4double xSec = theElectronData.GetCrossSection(theElectron, anElement); // Check cross section |
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118 | if(xSec<=0.) |
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119 | { |
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120 | theResult.SetStatusChange(isAlive); |
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121 | theResult.SetEnergyChange(theElectron->GetKineticEnergy()); |
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122 | theResult.SetMomentumChange(theElectron->GetMomentumDirection()); // new direction for the electron |
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123 | return &theResult; // DO-NOTHING condition |
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124 | } |
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125 | G4double photonEnergy = theElectronData.GetEquivalentPhotonEnergy(); |
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126 | G4double theElectronKinEnergy=theElectron->GetKineticEnergy(); |
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127 | if( theElectronKinEnergy < photonEnergy ) |
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128 | { |
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129 | G4cout << "G4ElectroNuclearReaction::ApplyYourself: photonEnergy is very high"<<G4endl; |
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130 | G4cout << "If this condition appears frequently, please contact Hans-Peter.Wellisch@cern.ch"<<G4endl; |
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131 | theResult.SetStatusChange(isAlive); |
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132 | theResult.SetEnergyChange(theElectron->GetKineticEnergy()); |
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133 | theResult.SetMomentumChange(theElectron->GetMomentumDirection()); // new direction for the electron |
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134 | return &theResult; // DO-NOTHING condition |
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135 | } |
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136 | G4double photonQ2 = theElectronData.GetEquivalentPhotonQ2(photonEnergy); |
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137 | G4double W=photonEnergy-photonQ2/dM; // Hadronic energy flow (W-energy) from the virtual photon |
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138 | if(getenv("debug_G4ElectroNuclearReaction") ) |
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139 | { |
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140 | G4cout << "G4ElectroNuclearReaction: Equivalent Energy = "<<W<<G4endl; |
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141 | } |
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142 | if(W<0.) |
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143 | { |
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144 | theResult.SetStatusChange(isAlive); |
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145 | theResult.SetEnergyChange(theElectron->GetKineticEnergy()); |
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146 | theResult.SetMomentumChange(theElectron->GetMomentumDirection()); // new direction for the electron |
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147 | return &theResult; // DO-NOTHING condition |
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148 | throw G4HadronicException(__FILE__, __LINE__, "G4ElectroNuclearReaction::ApplyYourself: negative equivalent energy"); |
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149 | } |
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150 | G4DynamicParticle* theDynamicPhoton = new |
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151 | G4DynamicParticle(G4Gamma::GammaDefinition(), |
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152 | G4ParticleMomentum(1.,0.,0.), photonEnergy*MeV); //->-* |
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153 | G4double sigNu=thePhotonData.GetCrossSection(theDynamicPhoton, anElement); // | |
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154 | theDynamicPhoton->SetKineticEnergy(W); // Redefine photon with equivalent energy | |
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155 | G4double sigK =thePhotonData.GetCrossSection(theDynamicPhoton, anElement); // | |
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156 | delete theDynamicPhoton; // <-------------------------------------------------------* |
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157 | G4double rndFraction = theElectronData.GetVirtualFactor(photonEnergy, photonQ2); |
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158 | if(sigNu*G4UniformRand()>sigK*rndFraction) |
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159 | { |
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160 | theResult.SetStatusChange(isAlive); |
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161 | theResult.SetEnergyChange(theElectron->GetKineticEnergy()); |
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162 | theResult.SetMomentumChange(theElectron->GetMomentumDirection()); // new direction for the electron |
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163 | return &theResult; // DO-NOTHING condition |
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164 | } |
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165 | theResult.SetStatusChange(isAlive); |
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166 | // Scatter an electron and make gamma+A reaction |
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167 | G4double iniE=theElectronKinEnergy+me; // Initial total energy of electron |
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168 | G4double finE=iniE-photonEnergy; // Final total energy of electron |
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169 | theResult.SetEnergyChange(std::max(0.,finE-me)); // Modifies the KINETIC ENERGY (Why not in the name?) |
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170 | G4double EEm=iniE*finE-me2; // Just an intermediate value to avoid "2*" |
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171 | G4double iniP=std::sqrt(iniE*iniE-me2); // Initial momentum of the electron |
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172 | G4double finP=std::sqrt(finE*finE-me2); // Final momentum of the electron |
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173 | G4double cost=(EEm+EEm-photonQ2)/iniP/finP; // std::cos(theta) for the electron scattering |
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174 | if(cost>1.) cost=1.; |
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175 | if(cost<-1.) cost=-1.; |
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176 | G4ThreeVector dir=theElectron->GetMomentumDirection(); // Direction of primary electron |
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177 | G4ThreeVector ort=dir.orthogonal(); // Not normed orthogonal vector (!) (to dir) |
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178 | G4ThreeVector ortx = ort.unit(); // First unit vector orthogonal to the direction |
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179 | G4ThreeVector orty = dir.cross(ortx); // Second unit vector orthoganal to the direction |
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180 | G4double sint=std::sqrt(1.-cost*cost); // Perpendicular component |
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181 | G4double phi=dpi*G4UniformRand(); // phi of scattered electron |
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182 | G4double sinx=sint*std::sin(phi); // x-component |
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183 | G4double siny=sint*std::cos(phi); // y-component |
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184 | G4ThreeVector findir=cost*dir+sinx*ortx+siny*orty; |
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185 | theResult.SetMomentumChange(findir); // new direction for the electron |
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186 | G4ThreeVector photonMomentum=iniP*dir-finP*findir; |
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187 | G4DynamicParticle localGamma(G4Gamma::GammaDefinition(), photonEnergy, photonMomentum); |
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188 | //G4DynamicParticle localGamma(G4Gamma::GammaDefinition(), photonDirection, photonEnergy); |
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189 | //G4DynamicParticle localGamma(G4Gamma::GammaDefinition(), photonLorentzVector); |
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190 | G4ThreeVector position(0,0,0); |
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191 | G4HadProjectile localTrack(localGamma); |
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192 | G4HadFinalState * result; |
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193 | if(photonEnergy < 3*GeV) |
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194 | { |
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195 | result = theLEModel.ApplyYourself(localTrack, aTargetNucleus, &theResult); |
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196 | } |
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197 | else |
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198 | { |
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199 | // G4cout << "0) Getting a high energy electro-nuclear reaction"<<G4endl; |
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200 | theHEModel->SetTransport(theCascade); |
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201 | theHEModel->SetHighEnergyGenerator(&theStringModel); |
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202 | theStringDecay = new G4ExcitedStringDecay(&theFragmentation); |
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203 | theStringModel.SetFragmentationModel(theStringDecay); |
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204 | theHEModel->SetMinEnergy(2.5*GeV); |
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205 | theHEModel->SetMaxEnergy(100*TeV); |
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206 | |
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207 | G4HadFinalState * aResult = theHEModel->ApplyYourself(localTrack, aTargetNucleus); |
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208 | for(G4int all = 0; all < aResult->GetNumberOfSecondaries(); all++) |
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209 | { |
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210 | theResult.AddSecondary(aResult->GetSecondary(all)); |
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211 | } |
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212 | aResult->SecondariesAreStale(); |
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213 | result = &theResult; |
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214 | } |
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215 | return result; |
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216 | } |
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217 | |
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218 | #endif |
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