[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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| 26 | // $Id: G4RPGLambdaInelastic.cc,v 1.1 2007/07/18 21:04:20 dennis Exp $ |
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[1228] | 27 | // GEANT4 tag $Name: geant4-09-03 $ |
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[819] | 28 | // |
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| 29 | |
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| 30 | #include "G4RPGLambdaInelastic.hh" |
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| 31 | #include "Randomize.hh" |
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| 32 | |
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| 33 | G4HadFinalState* |
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| 34 | G4RPGLambdaInelastic::ApplyYourself( const G4HadProjectile &aTrack, |
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| 35 | G4Nucleus &targetNucleus ) |
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| 36 | { |
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| 37 | const G4HadProjectile *originalIncident = &aTrack; |
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| 38 | |
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| 39 | // create the target particle |
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| 40 | |
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| 41 | G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle(); |
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| 42 | |
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| 43 | if( verboseLevel > 1 ) |
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| 44 | { |
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| 45 | const G4Material *targetMaterial = aTrack.GetMaterial(); |
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| 46 | G4cout << "G4RPGLambdaInelastic::ApplyYourself called" << G4endl; |
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| 47 | G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, "; |
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| 48 | G4cout << "target material = " << targetMaterial->GetName() << ", "; |
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| 49 | G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName() |
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| 50 | << G4endl; |
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| 51 | } |
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| 52 | |
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| 53 | // Fermi motion and evaporation |
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| 54 | // As of Geant3, the Fermi energy calculation had not been Done |
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| 55 | |
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| 56 | G4double ek = originalIncident->GetKineticEnergy()/MeV; |
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| 57 | G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV; |
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| 58 | G4ReactionProduct modifiedOriginal; |
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| 59 | modifiedOriginal = *originalIncident; |
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| 60 | |
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| 61 | G4double tkin = targetNucleus.Cinema( ek ); |
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| 62 | ek += tkin; |
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| 63 | modifiedOriginal.SetKineticEnergy( ek*MeV ); |
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| 64 | G4double et = ek + amas; |
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| 65 | G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
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| 66 | G4double pp = modifiedOriginal.GetMomentum().mag()/MeV; |
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| 67 | if( pp > 0.0 ) |
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| 68 | { |
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| 69 | G4ThreeVector momentum = modifiedOriginal.GetMomentum(); |
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| 70 | modifiedOriginal.SetMomentum( momentum * (p/pp) ); |
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| 71 | } |
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| 72 | // |
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| 73 | // calculate black track energies |
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| 74 | // |
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| 75 | tkin = targetNucleus.EvaporationEffects( ek ); |
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| 76 | ek -= tkin; |
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| 77 | modifiedOriginal.SetKineticEnergy( ek*MeV ); |
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| 78 | et = ek + amas; |
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| 79 | p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
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| 80 | pp = modifiedOriginal.GetMomentum().mag()/MeV; |
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| 81 | if( pp > 0.0 ) |
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| 82 | { |
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| 83 | G4ThreeVector momentum = modifiedOriginal.GetMomentum(); |
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| 84 | modifiedOriginal.SetMomentum( momentum * (p/pp) ); |
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| 85 | } |
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| 86 | |
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| 87 | G4ReactionProduct currentParticle = modifiedOriginal; |
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| 88 | G4ReactionProduct targetParticle; |
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| 89 | targetParticle = *originalTarget; |
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| 90 | currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere |
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| 91 | targetParticle.SetSide( -1 ); // target always goes in backward hemisphere |
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| 92 | G4bool incidentHasChanged = false; |
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| 93 | G4bool targetHasChanged = false; |
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| 94 | G4bool quasiElastic = false; |
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| 95 | G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles |
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| 96 | G4int vecLen = 0; |
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| 97 | vec.Initialize( 0 ); |
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| 98 | |
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| 99 | const G4double cutOff = 0.1; |
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| 100 | if( currentParticle.GetKineticEnergy()/MeV > cutOff ) |
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| 101 | Cascade( vec, vecLen, |
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| 102 | originalIncident, currentParticle, targetParticle, |
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| 103 | incidentHasChanged, targetHasChanged, quasiElastic ); |
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| 104 | |
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| 105 | CalculateMomenta( vec, vecLen, |
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| 106 | originalIncident, originalTarget, modifiedOriginal, |
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| 107 | targetNucleus, currentParticle, targetParticle, |
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| 108 | incidentHasChanged, targetHasChanged, quasiElastic ); |
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| 109 | |
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| 110 | SetUpChange( vec, vecLen, |
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| 111 | currentParticle, targetParticle, |
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| 112 | incidentHasChanged ); |
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| 113 | |
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| 114 | delete originalTarget; |
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| 115 | return &theParticleChange; |
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| 116 | } |
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| 117 | |
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| 118 | |
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| 119 | void G4RPGLambdaInelastic::Cascade( |
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| 120 | G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec, |
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| 121 | G4int& vecLen, |
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| 122 | const G4HadProjectile *originalIncident, |
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| 123 | G4ReactionProduct ¤tParticle, |
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| 124 | G4ReactionProduct &targetParticle, |
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| 125 | G4bool &incidentHasChanged, |
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| 126 | G4bool &targetHasChanged, |
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| 127 | G4bool &quasiElastic ) |
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| 128 | { |
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| 129 | // Derived from H. Fesefeldt's original FORTRAN code CASL0 |
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| 130 | // |
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| 131 | // Lambda undergoes interaction with nucleon within a nucleus. Check if it is |
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| 132 | // energetically possible to produce pions/kaons. In not, assume nuclear excitation |
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| 133 | // occurs and input particle is degraded in energy. No other particles are produced. |
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| 134 | // If reaction is possible, find the correct number of pions/protons/neutrons |
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| 135 | // produced using an interpolation to multiplicity data. Replace some pions or |
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| 136 | // protons/neutrons by kaons or strange baryons according to the average |
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| 137 | // multiplicity per Inelastic reaction. |
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| 138 | |
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| 139 | const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV; |
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| 140 | const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV; |
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| 141 | const G4double targetMass = targetParticle.GetMass()/MeV; |
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| 142 | G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal + |
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| 143 | targetMass*targetMass + |
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| 144 | 2.0*targetMass*etOriginal ); |
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| 145 | G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal); |
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| 146 | if( availableEnergy <= G4PionPlus::PionPlus()->GetPDGMass()/MeV ) |
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| 147 | { |
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| 148 | quasiElastic = true; |
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| 149 | return; |
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| 150 | } |
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| 151 | static G4bool first = true; |
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| 152 | const G4int numMul = 1200; |
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| 153 | const G4int numSec = 60; |
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| 154 | static G4double protmul[numMul], protnorm[numSec]; // proton constants |
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| 155 | static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants |
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| 156 | |
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| 157 | // np = number of pi+, nm = number of pi-, nz = number of pi0 |
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| 158 | |
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| 159 | G4int counter, nt=0, np=0, nm=0, nz=0; |
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| 160 | G4double test; |
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| 161 | const G4double c = 1.25; |
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| 162 | const G4double b[] = { 0.70, 0.35 }; |
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| 163 | if( first ) { // compute normalization constants, this will only be Done once |
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| 164 | first = false; |
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| 165 | G4int i; |
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| 166 | for( i=0; i<numMul; ++i )protmul[i] = 0.0; |
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| 167 | for( i=0; i<numSec; ++i )protnorm[i] = 0.0; |
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| 168 | counter = -1; |
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| 169 | for( np=0; np<(numSec/3); ++np ) { |
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| 170 | for( nm=std::max(0,np-2); nm<=(np+1); ++nm ) { |
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| 171 | for( nz=0; nz<numSec/3; ++nz ) { |
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| 172 | if( ++counter < numMul ) { |
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| 173 | nt = np+nm+nz; |
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| 174 | if( nt>0 && nt<=numSec ) { |
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| 175 | protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c); |
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| 176 | protnorm[nt-1] += protmul[counter]; |
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| 177 | } |
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| 178 | } |
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| 179 | } |
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| 180 | } |
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| 181 | } |
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| 182 | for( i=0; i<numMul; ++i )neutmul[i] = 0.0; |
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| 183 | for( i=0; i<numSec; ++i )neutnorm[i] = 0.0; |
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| 184 | counter = -1; |
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| 185 | for( np=0; np<numSec/3; ++np ) { |
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| 186 | for( nm=std::max(0,np-1); nm<=(np+2); ++nm ) { |
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| 187 | for( nz=0; nz<numSec/3; ++nz ) { |
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| 188 | if( ++counter < numMul ) { |
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| 189 | nt = np+nm+nz; |
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| 190 | if( nt>0 && nt<=numSec ) { |
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| 191 | neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c); |
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| 192 | neutnorm[nt-1] += neutmul[counter]; |
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| 193 | } |
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| 194 | } |
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| 195 | } |
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| 196 | } |
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| 197 | } |
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| 198 | for( i=0; i<numSec; ++i ) { |
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| 199 | if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i]; |
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| 200 | if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i]; |
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| 201 | } |
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| 202 | } // end of initialization |
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| 203 | |
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| 204 | const G4double expxu = 82.; // upper bound for arg. of exp |
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| 205 | const G4double expxl = -expxu; // lower bound for arg. of exp |
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| 206 | G4ParticleDefinition *aNeutron = G4Neutron::Neutron(); |
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| 207 | G4ParticleDefinition *aProton = G4Proton::Proton(); |
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| 208 | G4ParticleDefinition *aSigmaPlus = G4SigmaPlus::SigmaPlus(); |
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| 209 | G4ParticleDefinition *aSigmaMinus = G4SigmaMinus::SigmaMinus(); |
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| 210 | G4ParticleDefinition *aSigmaZero = G4SigmaZero::SigmaZero(); |
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| 211 | |
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| 212 | // energetically possible to produce pion(s) --> inelastic scattering |
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| 213 | // otherwise quasi-elastic scattering |
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| 214 | |
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| 215 | G4double n, anpn; |
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| 216 | GetNormalizationConstant( availableEnergy, n, anpn ); |
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| 217 | G4double ran = G4UniformRand(); |
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| 218 | G4double dum, excs = 0.0; |
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| 219 | if( targetParticle.GetDefinition() == aProton ) { |
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| 220 | counter = -1; |
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| 221 | for( np=0; np<numSec/3 && ran>=excs; ++np ) { |
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| 222 | for( nm=std::max(0,np-2); nm<=(np+1) && ran>=excs; ++nm ) { |
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| 223 | for( nz=0; nz<numSec/3 && ran>=excs; ++nz ) { |
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| 224 | if( ++counter < numMul ) { |
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| 225 | nt = np+nm+nz; |
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| 226 | if( nt>0 && nt<=numSec ) { |
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| 227 | test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) ); |
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| 228 | dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n); |
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| 229 | if( std::fabs(dum) < 1.0 ) { |
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| 230 | if( test >= 1.0e-10 )excs += dum*test; |
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| 231 | } else { |
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| 232 | excs += dum*test; |
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| 233 | } |
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| 234 | } |
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| 235 | } |
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| 236 | } |
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| 237 | } |
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| 238 | } |
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| 239 | if( ran >= excs ) // 3 previous loops continued to the end |
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| 240 | { |
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| 241 | quasiElastic = true; |
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| 242 | return; |
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| 243 | } |
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| 244 | np--; nm--; nz--; |
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| 245 | G4int ncht = std::max( 1, np-nm ); |
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| 246 | switch( ncht ) { |
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| 247 | case 1: |
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| 248 | currentParticle.SetDefinitionAndUpdateE( aSigmaPlus ); |
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| 249 | incidentHasChanged = true; |
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| 250 | break; |
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| 251 | case 2: |
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| 252 | if( G4UniformRand() < 0.5 ) { |
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| 253 | if( G4UniformRand() < 0.5 ) { |
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| 254 | currentParticle.SetDefinitionAndUpdateE( aSigmaZero ); |
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| 255 | incidentHasChanged = true; |
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| 256 | } |
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| 257 | } else { |
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| 258 | currentParticle.SetDefinitionAndUpdateE( aSigmaPlus ); |
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| 259 | incidentHasChanged = true; |
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| 260 | targetParticle.SetDefinitionAndUpdateE( aNeutron ); |
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| 261 | targetHasChanged = true; |
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| 262 | } |
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| 263 | break; |
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| 264 | case 3: |
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| 265 | if( G4UniformRand() < 0.5 ) { |
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| 266 | if( G4UniformRand() < 0.5 ) { |
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| 267 | currentParticle.SetDefinitionAndUpdateE( aSigmaZero ); |
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| 268 | incidentHasChanged = true; |
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| 269 | } |
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| 270 | targetParticle.SetDefinitionAndUpdateE( aNeutron ); |
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| 271 | targetHasChanged = true; |
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| 272 | } else { |
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| 273 | currentParticle.SetDefinitionAndUpdateE( aSigmaMinus ); |
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| 274 | incidentHasChanged = true; |
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| 275 | } |
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| 276 | break; |
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| 277 | default: |
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| 278 | currentParticle.SetDefinitionAndUpdateE( aSigmaMinus ); |
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| 279 | incidentHasChanged = true; |
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| 280 | targetParticle.SetDefinitionAndUpdateE( aNeutron ); |
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| 281 | targetHasChanged = true; |
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| 282 | break; |
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| 283 | } |
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| 284 | } |
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| 285 | else // target must be a neutron |
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| 286 | { |
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| 287 | counter = -1; |
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| 288 | for( np=0; np<numSec/3 && ran>=excs; ++np ) { |
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| 289 | for( nm=std::max(0,np-1); nm<=(np+2) && ran>=excs; ++nm ) { |
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| 290 | for( nz=0; nz<numSec/3 && ran>=excs; ++nz ) { |
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| 291 | if( ++counter < numMul ) { |
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| 292 | nt = np+nm+nz; |
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| 293 | if( nt>0 && nt<=numSec ) { |
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| 294 | test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) ); |
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| 295 | dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n); |
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| 296 | if( std::fabs(dum) < 1.0 ) { |
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| 297 | if( test >= 1.0e-10 )excs += dum*test; |
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| 298 | } else { |
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| 299 | excs += dum*test; |
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| 300 | } |
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| 301 | } |
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| 302 | } |
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| 303 | } |
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| 304 | } |
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| 305 | } |
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| 306 | if( ran >= excs ) // 3 previous loops continued to the end |
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| 307 | { |
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| 308 | quasiElastic = true; |
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| 309 | return; |
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| 310 | } |
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| 311 | np--; nm--; nz--; |
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| 312 | G4int ncht = std::max( 1, np-nm+3 ); |
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| 313 | switch( ncht ) { |
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| 314 | case 1: |
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| 315 | currentParticle.SetDefinitionAndUpdateE( aSigmaPlus ); |
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| 316 | incidentHasChanged = true; |
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| 317 | targetParticle.SetDefinitionAndUpdateE( aProton ); |
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| 318 | targetHasChanged = true; |
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| 319 | break; |
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| 320 | case 2: |
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| 321 | if( G4UniformRand() < 0.5 ) { |
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| 322 | if( G4UniformRand() < 0.5 ) { |
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| 323 | currentParticle.SetDefinitionAndUpdateE( aSigmaZero ); |
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| 324 | incidentHasChanged = true; |
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| 325 | } |
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| 326 | targetParticle.SetDefinitionAndUpdateE( aProton ); |
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| 327 | targetHasChanged = true; |
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| 328 | } else { |
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| 329 | currentParticle.SetDefinitionAndUpdateE( aSigmaPlus ); |
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| 330 | incidentHasChanged = true; |
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| 331 | } |
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| 332 | break; |
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| 333 | case 3: |
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| 334 | if( G4UniformRand() < 0.5 ) { |
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| 335 | if( G4UniformRand() < 0.5 ) { |
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| 336 | currentParticle.SetDefinitionAndUpdateE( aSigmaZero ); |
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| 337 | incidentHasChanged = true; |
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| 338 | } |
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| 339 | } else { |
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| 340 | currentParticle.SetDefinitionAndUpdateE( aSigmaMinus ); |
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| 341 | incidentHasChanged = true; |
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| 342 | targetParticle.SetDefinitionAndUpdateE( aProton ); |
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| 343 | targetHasChanged = true; |
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| 344 | } |
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| 345 | break; |
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| 346 | default: |
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| 347 | currentParticle.SetDefinitionAndUpdateE( aSigmaMinus ); |
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| 348 | incidentHasChanged = true; |
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| 349 | break; |
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| 350 | } |
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| 351 | } |
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| 352 | SetUpPions( np, nm, nz, vec, vecLen ); |
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| 353 | return; |
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| 354 | } |
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| 355 | |
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| 356 | /* end of file */ |
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| 357 | |
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