[819] | 1 | // |
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| 2 | // ******************************************************************** |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 24 | // ******************************************************************** |
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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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