[819] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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[962] | 26 | // $Id: G4RPGNeutronInelastic.cc,v 1.4 2008/05/05 21:21:55 dennis Exp $ |
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[1340] | 27 | // GEANT4 tag $Name: geant4-09-03-ref-09 $ |
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[819] | 28 | // |
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| 29 | |
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| 30 | #include "G4RPGNeutronInelastic.hh" |
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| 31 | #include "Randomize.hh" |
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| 32 | |
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[962] | 33 | |
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| 34 | G4HadFinalState* |
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| 35 | G4RPGNeutronInelastic::ApplyYourself(const G4HadProjectile& aTrack, |
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| 36 | G4Nucleus& targetNucleus) |
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| 37 | { |
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| 38 | theParticleChange.Clear(); |
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| 39 | const G4HadProjectile* originalIncident = &aTrack; |
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| 40 | |
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| 41 | // |
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| 42 | // create the target particle |
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| 43 | // |
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| 44 | G4DynamicParticle* originalTarget = targetNucleus.ReturnTargetParticle(); |
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| 45 | |
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| 46 | G4ReactionProduct modifiedOriginal; |
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| 47 | modifiedOriginal = *originalIncident; |
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| 48 | G4ReactionProduct targetParticle; |
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| 49 | targetParticle = *originalTarget; |
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| 50 | if( originalIncident->GetKineticEnergy()/GeV < 0.01 + 2.*G4UniformRand()/9. ) |
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[819] | 51 | { |
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[962] | 52 | SlowNeutron(originalIncident,modifiedOriginal,targetParticle,targetNucleus ); |
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| 53 | delete originalTarget; |
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| 54 | return &theParticleChange; |
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| 55 | } |
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| 56 | |
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| 57 | // |
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| 58 | // Fermi motion and evaporation |
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| 59 | // As of Geant3, the Fermi energy calculation had not been Done |
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| 60 | // |
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| 61 | G4double ek = originalIncident->GetKineticEnergy()/MeV; |
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| 62 | G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV; |
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[819] | 63 | |
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[962] | 64 | G4double tkin = targetNucleus.Cinema( ek ); |
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| 65 | ek += tkin; |
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| 66 | modifiedOriginal.SetKineticEnergy( ek*MeV ); |
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| 67 | G4double et = ek + amas; |
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| 68 | G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
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| 69 | G4double pp = modifiedOriginal.GetMomentum().mag()/MeV; |
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| 70 | if( pp > 0.0 ) |
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| 71 | { |
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| 72 | G4ThreeVector momentum = modifiedOriginal.GetMomentum(); |
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| 73 | modifiedOriginal.SetMomentum( momentum * (p/pp) ); |
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| 74 | } |
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| 75 | // |
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| 76 | // calculate black track energies |
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| 77 | // |
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| 78 | tkin = targetNucleus.EvaporationEffects( ek ); |
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| 79 | ek -= tkin; |
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| 80 | modifiedOriginal.SetKineticEnergy(ek); |
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| 81 | et = ek + amas; |
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| 82 | p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
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| 83 | pp = modifiedOriginal.GetMomentum().mag(); |
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| 84 | if( pp > 0.0 ) |
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| 85 | { |
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| 86 | G4ThreeVector momentum = modifiedOriginal.GetMomentum(); |
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| 87 | modifiedOriginal.SetMomentum( momentum * (p/pp) ); |
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| 88 | } |
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| 89 | const G4double cutOff = 0.1; |
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| 90 | if( modifiedOriginal.GetKineticEnergy()/MeV <= cutOff ) |
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| 91 | { |
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| 92 | SlowNeutron( originalIncident, modifiedOriginal, targetParticle, targetNucleus ); |
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| 93 | delete originalTarget; |
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| 94 | return &theParticleChange; |
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| 95 | } |
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| 96 | |
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| 97 | G4ReactionProduct currentParticle = modifiedOriginal; |
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| 98 | currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere |
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| 99 | targetParticle.SetSide( -1 ); // target always goes in backward hemisphere |
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| 100 | G4bool incidentHasChanged = false; |
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| 101 | G4bool targetHasChanged = false; |
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| 102 | G4bool quasiElastic = false; |
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| 103 | G4FastVector<G4ReactionProduct,256> vec; // vec will contain sec. particles |
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| 104 | G4int vecLen = 0; |
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| 105 | vec.Initialize( 0 ); |
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[819] | 106 | |
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[962] | 107 | InitialCollision(vec, vecLen, currentParticle, targetParticle, |
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| 108 | incidentHasChanged, targetHasChanged); |
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| 109 | |
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| 110 | CalculateMomenta(vec, vecLen, |
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| 111 | originalIncident, originalTarget, modifiedOriginal, |
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| 112 | targetNucleus, currentParticle, targetParticle, |
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| 113 | incidentHasChanged, targetHasChanged, quasiElastic); |
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| 114 | |
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| 115 | SetUpChange(vec, vecLen, |
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| 116 | currentParticle, targetParticle, |
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| 117 | incidentHasChanged); |
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| 118 | |
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| 119 | delete originalTarget; |
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| 120 | return &theParticleChange; |
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| 121 | } |
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| 122 | |
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| 123 | void |
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| 124 | G4RPGNeutronInelastic::SlowNeutron(const G4HadProjectile* originalIncident, |
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| 125 | G4ReactionProduct& modifiedOriginal, |
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| 126 | G4ReactionProduct& targetParticle, |
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| 127 | G4Nucleus& targetNucleus) |
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| 128 | { |
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| 129 | const G4double A = targetNucleus.GetN(); // atomic weight |
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| 130 | const G4double Z = targetNucleus.GetZ(); // atomic number |
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| 131 | |
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| 132 | G4double currentKinetic = modifiedOriginal.GetKineticEnergy()/MeV; |
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| 133 | G4double currentMass = modifiedOriginal.GetMass()/MeV; |
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| 134 | if( A < 1.5 ) // Hydrogen |
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| 135 | { |
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[819] | 136 | // |
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[962] | 137 | // very simple simulation of scattering angle and energy |
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| 138 | // nonrelativistic approximation with isotropic angular |
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| 139 | // distribution in the cms system |
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[819] | 140 | // |
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[962] | 141 | G4double cost1, eka = 0.0; |
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| 142 | while (eka <= 0.0) |
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[819] | 143 | { |
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[962] | 144 | cost1 = -1.0 + 2.0*G4UniformRand(); |
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| 145 | eka = 1.0 + 2.0*cost1*A + A*A; |
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[819] | 146 | } |
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[962] | 147 | G4double cost = std::min( 1.0, std::max( -1.0, (A*cost1+1.0)/std::sqrt(eka) ) ); |
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| 148 | eka /= (1.0+A)*(1.0+A); |
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| 149 | G4double ek = currentKinetic*MeV/GeV; |
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| 150 | G4double amas = currentMass*MeV/GeV; |
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| 151 | ek *= eka; |
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| 152 | G4double en = ek + amas; |
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| 153 | G4double p = std::sqrt(std::abs(en*en-amas*amas)); |
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| 154 | G4double sint = std::sqrt(std::abs(1.0-cost*cost)); |
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| 155 | G4double phi = G4UniformRand()*twopi; |
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| 156 | G4double px = sint*std::sin(phi); |
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| 157 | G4double py = sint*std::cos(phi); |
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| 158 | G4double pz = cost; |
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| 159 | targetParticle.SetMomentum( px*GeV, py*GeV, pz*GeV ); |
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| 160 | G4double pxO = originalIncident->Get4Momentum().x()/GeV; |
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| 161 | G4double pyO = originalIncident->Get4Momentum().y()/GeV; |
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| 162 | G4double pzO = originalIncident->Get4Momentum().z()/GeV; |
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| 163 | G4double ptO = pxO*pxO + pyO+pyO; |
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| 164 | if( ptO > 0.0 ) |
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[819] | 165 | { |
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[962] | 166 | G4double pO = std::sqrt(pxO*pxO+pyO*pyO+pzO*pzO); |
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| 167 | cost = pzO/pO; |
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| 168 | sint = 0.5*(std::sqrt(std::abs((1.0-cost)*(1.0+cost)))+std::sqrt(ptO)/pO); |
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| 169 | G4double ph = pi/2.0; |
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| 170 | if( pyO < 0.0 )ph = ph*1.5; |
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| 171 | if( std::abs(pxO) > 0.000001 )ph = std::atan2(pyO,pxO); |
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| 172 | G4double cosp = std::cos(ph); |
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| 173 | G4double sinp = std::sin(ph); |
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| 174 | px = cost*cosp*px - sinp*py+sint*cosp*pz; |
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| 175 | py = cost*sinp*px + cosp*py+sint*sinp*pz; |
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| 176 | pz = -sint*px + cost*pz; |
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[819] | 177 | } |
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[962] | 178 | else |
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[819] | 179 | { |
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[962] | 180 | if( pz < 0.0 )pz *= -1.0; |
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[819] | 181 | } |
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[962] | 182 | G4double pu = std::sqrt(px*px+py*py+pz*pz); |
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| 183 | modifiedOriginal.SetMomentum( targetParticle.GetMomentum() * (p/pu) ); |
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| 184 | modifiedOriginal.SetKineticEnergy( ek*GeV ); |
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[819] | 185 | |
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[962] | 186 | targetParticle.SetMomentum( |
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| 187 | originalIncident->Get4Momentum().vect() - modifiedOriginal.GetMomentum() ); |
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| 188 | G4double pp = targetParticle.GetMomentum().mag(); |
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| 189 | G4double tarmas = targetParticle.GetMass(); |
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| 190 | targetParticle.SetTotalEnergy( std::sqrt( pp*pp + tarmas*tarmas ) ); |
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[819] | 191 | |
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[962] | 192 | theParticleChange.SetEnergyChange( modifiedOriginal.GetKineticEnergy() ); |
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| 193 | G4DynamicParticle *pd = new G4DynamicParticle; |
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| 194 | pd->SetDefinition( targetParticle.GetDefinition() ); |
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| 195 | pd->SetMomentum( targetParticle.GetMomentum() ); |
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| 196 | theParticleChange.AddSecondary( pd ); |
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| 197 | return; |
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| 198 | } |
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| 199 | |
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| 200 | G4FastVector<G4ReactionProduct,4> vec; // vec will contain the secondary particles |
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| 201 | G4int vecLen = 0; |
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| 202 | vec.Initialize( 0 ); |
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[819] | 203 | |
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[962] | 204 | G4double theAtomicMass = targetNucleus.AtomicMass( A, Z ); |
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| 205 | G4double massVec[9]; |
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| 206 | massVec[0] = targetNucleus.AtomicMass( A+1.0, Z ); |
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| 207 | massVec[1] = theAtomicMass; |
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| 208 | massVec[2] = 0.; |
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| 209 | if (Z > 1.0) massVec[2] = targetNucleus.AtomicMass(A, Z-1.0); |
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| 210 | massVec[3] = 0.; |
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| 211 | if (Z > 1.0 && A > 1.0) massVec[3] = targetNucleus.AtomicMass(A-1.0, Z-1.0 ); |
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| 212 | massVec[4] = 0.; |
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| 213 | if (Z > 1.0 && A > 2.0 && A-2.0 > Z-1.0) |
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| 214 | massVec[4] = targetNucleus.AtomicMass( A-2.0, Z-1.0 ); |
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| 215 | massVec[5] = 0.; |
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| 216 | if (Z > 2.0 && A > 3.0 && A-3.0 > Z-2.0) |
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| 217 | massVec[5] = targetNucleus.AtomicMass( A-3.0, Z-2.0 ); |
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| 218 | massVec[6] = 0.; |
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| 219 | if (A > 1.0 && A-1.0 > Z) massVec[6] = targetNucleus.AtomicMass(A-1.0, Z); |
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| 220 | massVec[7] = massVec[3]; |
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| 221 | massVec[8] = 0.; |
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| 222 | if (Z > 2.0 && A > 1.0) massVec[8] = targetNucleus.AtomicMass( A-1.0,Z-2.0 ); |
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[819] | 223 | |
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[962] | 224 | twoBody.NuclearReaction(vec, vecLen, originalIncident, |
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| 225 | targetNucleus, theAtomicMass, massVec ); |
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[819] | 226 | |
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[962] | 227 | theParticleChange.SetStatusChange( stopAndKill ); |
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| 228 | theParticleChange.SetEnergyChange( 0.0 ); |
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[819] | 229 | |
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[962] | 230 | G4DynamicParticle* pd; |
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| 231 | for( G4int i=0; i<vecLen; ++i ) { |
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| 232 | pd = new G4DynamicParticle(); |
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| 233 | pd->SetDefinition( vec[i]->GetDefinition() ); |
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| 234 | pd->SetMomentum( vec[i]->GetMomentum() ); |
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| 235 | theParticleChange.AddSecondary( pd ); |
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| 236 | delete vec[i]; |
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[819] | 237 | } |
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[962] | 238 | } |
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| 239 | |
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| 240 | |
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| 241 | // Initial Collision |
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| 242 | // selects the particle types arising from the initial collision of |
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| 243 | // the neutron and target nucleon. Secondaries are assigned to |
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| 244 | // forward and backward reaction hemispheres, but final state energies |
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| 245 | // and momenta are not calculated here. |
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| 246 | |
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| 247 | void |
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| 248 | G4RPGNeutronInelastic::InitialCollision(G4FastVector<G4ReactionProduct,256>& vec, |
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| 249 | G4int& vecLen, |
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| 250 | G4ReactionProduct& currentParticle, |
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| 251 | G4ReactionProduct& targetParticle, |
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| 252 | G4bool& incidentHasChanged, |
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| 253 | G4bool& targetHasChanged) |
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| 254 | { |
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| 255 | G4double KE = currentParticle.GetKineticEnergy()/GeV; |
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[819] | 256 | |
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[962] | 257 | G4int mult; |
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| 258 | G4int partType; |
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| 259 | std::vector<G4int> fsTypes; |
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| 260 | G4int part1; |
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| 261 | G4int part2; |
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| 262 | |
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| 263 | G4double testCharge; |
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| 264 | G4double testBaryon; |
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| 265 | G4double testStrange; |
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| 266 | |
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| 267 | // Get particle types according to incident and target types |
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| 268 | |
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| 269 | if (targetParticle.GetDefinition() == particleDef[neu]) { |
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| 270 | mult = GetMultiplicityT1(KE); |
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| 271 | fsTypes = GetFSPartTypesForNN(mult, KE); |
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| 272 | |
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| 273 | part1 = fsTypes[0]; |
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| 274 | part2 = fsTypes[1]; |
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| 275 | currentParticle.SetDefinition(particleDef[part1]); |
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| 276 | targetParticle.SetDefinition(particleDef[part2]); |
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| 277 | if (part1 == pro) { |
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| 278 | if (part2 == neu) { |
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| 279 | if (G4UniformRand() > 0.5) { |
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| 280 | incidentHasChanged = true; |
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| 281 | } else { |
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| 282 | targetHasChanged = true; |
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| 283 | currentParticle.SetDefinition(particleDef[part2]); |
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| 284 | targetParticle.SetDefinition(particleDef[part1]); |
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| 285 | } |
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| 286 | } else { |
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| 287 | targetHasChanged = true; |
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| 288 | incidentHasChanged = true; |
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[819] | 289 | } |
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| 290 | |
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[962] | 291 | } else { // neutron |
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| 292 | if (part2 > neu && part2 < xi0) targetHasChanged = true; |
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[819] | 293 | } |
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[962] | 294 | |
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| 295 | testCharge = 0.0; |
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| 296 | testBaryon = 2.0; |
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| 297 | testStrange = 0.0; |
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| 298 | |
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| 299 | } else { // target was a proton |
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| 300 | mult = GetMultiplicityT0(KE); |
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| 301 | fsTypes = GetFSPartTypesForNP(mult, KE); |
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| 302 | |
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| 303 | part1 = fsTypes[0]; |
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| 304 | part2 = fsTypes[1]; |
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| 305 | currentParticle.SetDefinition(particleDef[part1]); |
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| 306 | targetParticle.SetDefinition(particleDef[part2]); |
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| 307 | if (part1 == pro) { |
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| 308 | if (part2 == pro) { |
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| 309 | incidentHasChanged = true; |
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| 310 | } else if (part2 == neu) { |
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| 311 | if (G4UniformRand() > 0.5) { |
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| 312 | incidentHasChanged = true; |
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| 313 | targetHasChanged = true; |
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| 314 | } else { |
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| 315 | currentParticle.SetDefinition(particleDef[part2]); |
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| 316 | targetParticle.SetDefinition(particleDef[part1]); |
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| 317 | } |
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| 318 | |
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| 319 | } else if (part2 > neu && part2 < xi0) { |
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| 320 | incidentHasChanged = true; |
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| 321 | targetHasChanged = true; |
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[819] | 322 | } |
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[962] | 323 | |
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| 324 | } else { // neutron |
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| 325 | targetHasChanged = true; |
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[819] | 326 | } |
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[962] | 327 | |
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| 328 | testCharge = 1.0; |
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| 329 | testBaryon = 2.0; |
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| 330 | testStrange = 0.0; |
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[819] | 331 | } |
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| 332 | |
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[962] | 333 | // if (mult == 2 && !incidentHasChanged && !targetHasChanged) |
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| 334 | // quasiElastic = true; |
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| 335 | |
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| 336 | // Remove incident and target from fsTypes |
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| 337 | |
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| 338 | fsTypes.erase(fsTypes.begin()); |
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| 339 | fsTypes.erase(fsTypes.begin()); |
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| 340 | |
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| 341 | // Remaining particles are secondaries. Put them into vec. |
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| 342 | |
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| 343 | G4ReactionProduct* rp(0); |
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| 344 | for(G4int i=0; i < mult-2; ++i ) { |
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| 345 | partType = fsTypes[i]; |
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| 346 | rp = new G4ReactionProduct(); |
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| 347 | rp->SetDefinition(particleDef[partType]); |
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| 348 | (G4UniformRand() < 0.5) ? rp->SetSide(-1) : rp->SetSide(1); |
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| 349 | vec.SetElement(vecLen++, rp); |
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| 350 | } |
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| 351 | |
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| 352 | // Check conservation of charge, strangeness, baryon number |
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| 353 | |
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| 354 | CheckQnums(vec, vecLen, currentParticle, targetParticle, |
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| 355 | testCharge, testBaryon, testStrange); |
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| 356 | |
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| 357 | return; |
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| 358 | } |
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