[1197] | 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: G4VHadronElastic.cc,v 1.4 2009/09/23 14:37:44 vnivanch Exp $ |
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[1228] | 27 | // GEANT4 tag $Name: geant4-09-03 $ |
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[1197] | 28 | // |
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| 29 | // Geant4 Header : G4VHadronElastic |
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| 30 | // |
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| 31 | // Author : V.Ivanchenko 29 June 2009 (redesign old elastic model) |
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| 32 | // |
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| 33 | // Modified: |
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| 34 | // |
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| 35 | // |
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| 36 | |
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| 37 | #include "G4VHadronElastic.hh" |
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| 38 | #include "G4ParticleTable.hh" |
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| 39 | #include "G4ParticleDefinition.hh" |
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| 40 | #include "G4IonTable.hh" |
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| 41 | #include "Randomize.hh" |
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| 42 | #include "G4Proton.hh" |
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| 43 | #include "G4Neutron.hh" |
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| 44 | #include "G4Deuteron.hh" |
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| 45 | #include "G4Alpha.hh" |
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| 46 | #include "G4Pow.hh" |
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| 47 | |
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| 48 | G4VHadronElastic::G4VHadronElastic(const G4String& name) |
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| 49 | : G4HadronicInteraction(name) |
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| 50 | { |
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| 51 | SetMinEnergy( 0.0*GeV ); |
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| 52 | SetMaxEnergy( 100.*TeV ); |
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| 53 | lowestEnergyLimit= 1.e-6*eV; |
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| 54 | |
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| 55 | theProton = G4Proton::Proton(); |
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| 56 | theNeutron = G4Neutron::Neutron(); |
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| 57 | theDeuteron = G4Deuteron::Deuteron(); |
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| 58 | theAlpha = G4Alpha::Alpha(); |
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| 59 | } |
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| 60 | |
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| 61 | G4VHadronElastic::~G4VHadronElastic() |
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| 62 | {} |
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| 63 | |
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| 64 | G4HadFinalState* G4VHadronElastic::ApplyYourself( |
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| 65 | const G4HadProjectile& aTrack, G4Nucleus& targetNucleus) |
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| 66 | { |
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| 67 | theParticleChange.Clear(); |
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| 68 | |
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| 69 | const G4HadProjectile* aParticle = &aTrack; |
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| 70 | G4double ekin = aParticle->GetKineticEnergy(); |
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| 71 | if(ekin <= lowestEnergyLimit) { |
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| 72 | theParticleChange.SetEnergyChange(ekin); |
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| 73 | theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit()); |
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| 74 | return &theParticleChange; |
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| 75 | } |
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| 76 | |
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| 77 | G4double aTarget = targetNucleus.GetN(); |
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| 78 | G4double zTarget = targetNucleus.GetZ(); |
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| 79 | |
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| 80 | G4double plab = aParticle->GetTotalMomentum(); |
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| 81 | |
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| 82 | // Scattered particle referred to axis of incident particle |
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| 83 | const G4ParticleDefinition* theParticle = aParticle->GetDefinition(); |
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| 84 | G4double m1 = theParticle->GetPDGMass(); |
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| 85 | |
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| 86 | G4int Z = static_cast<G4int>(zTarget+0.5); |
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| 87 | G4int A = static_cast<G4int>(aTarget+0.5); |
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| 88 | if (verboseLevel>1) { |
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| 89 | G4cout << "G4VHadronElastic: " |
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| 90 | << aParticle->GetDefinition()->GetParticleName() |
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| 91 | << " Plab(GeV/c)= " << plab/GeV |
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| 92 | << " Ekin(MeV) = " << ekin/MeV |
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| 93 | << " scattered off Z= " << Z |
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| 94 | << " A= " << A |
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| 95 | << G4endl; |
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| 96 | } |
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| 97 | G4ParticleDefinition * theDef = 0; |
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| 98 | |
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| 99 | if(Z == 1 && A == 1) theDef = theProton; |
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| 100 | else if (Z == 1 && A == 2) theDef = theDeuteron; |
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| 101 | else if (Z == 1 && A == 3) theDef = G4Triton::Triton(); |
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| 102 | else if (Z == 2 && A == 3) theDef = G4He3::He3(); |
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| 103 | else if (Z == 2 && A == 4) theDef = theAlpha; |
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| 104 | else theDef = G4ParticleTable::GetParticleTable()->FindIon(Z,A,0,Z); |
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| 105 | |
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| 106 | G4double m2 = theDef->GetPDGMass(); |
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| 107 | G4LorentzVector lv1 = aParticle->Get4Momentum(); |
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| 108 | G4LorentzVector lv(0.0,0.0,0.0,m2); |
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| 109 | lv += lv1; |
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| 110 | |
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| 111 | G4ThreeVector bst = lv.boostVector(); |
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| 112 | lv1.boost(-bst); |
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| 113 | |
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| 114 | G4ThreeVector p1 = lv1.vect(); |
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| 115 | momentumCMS = p1.mag(); |
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| 116 | G4double tmax = 4.0*momentumCMS*momentumCMS; |
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| 117 | |
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| 118 | // Sampling in CM system |
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| 119 | G4double t = SampleInvariantT(theParticle, plab, Z, A); |
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| 120 | G4double phi = G4UniformRand()*CLHEP::twopi; |
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| 121 | G4double cost = 1. - 2.0*t/tmax; |
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| 122 | G4double sint; |
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| 123 | |
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| 124 | // problem in sampling |
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| 125 | if(cost > 1.0 || cost < -1.0) { |
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| 126 | if(verboseLevel > 0) { |
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| 127 | G4cout << "G4VHadronElastic WARNING cost= " << cost |
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| 128 | << " after scattering of " |
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| 129 | << aParticle->GetDefinition()->GetParticleName() |
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| 130 | << " p(GeV/c)= " << plab |
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| 131 | << " on " << theDef->GetParticleName() |
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| 132 | << G4endl; |
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| 133 | } |
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| 134 | cost = 1.0; |
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| 135 | sint = 0.0; |
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| 136 | |
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| 137 | // normal situation |
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| 138 | } else { |
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| 139 | sint = std::sqrt((1.0-cost)*(1.0+cost)); |
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| 140 | } |
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| 141 | if (verboseLevel>1) { |
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| 142 | G4cout << " t= " << t << " tmax= " << tmax |
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| 143 | << " Pcms= " << momentumCMS << "cos(t)=" << cost |
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| 144 | << " std::sin(t)=" << sint << G4endl; |
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| 145 | } |
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| 146 | G4ThreeVector v1(sint*std::cos(phi),sint*std::sin(phi),cost); |
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| 147 | v1 *= momentumCMS; |
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| 148 | G4LorentzVector nlv1(v1.x(),v1.y(),v1.z(), |
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| 149 | std::sqrt(momentumCMS*momentumCMS + m1*m1)); |
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| 150 | |
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| 151 | nlv1.boost(bst); |
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| 152 | |
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| 153 | G4double eFinal = nlv1.e() - m1; |
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| 154 | if (verboseLevel > 1) { |
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| 155 | G4cout <<" m= " << m1 << " Efin(MeV)= " << eFinal |
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| 156 | << " Proj: 4-mom " << lv1 << " Final: " << nlv1 |
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| 157 | << G4endl; |
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| 158 | } |
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| 159 | if(eFinal <= lowestEnergyLimit) { |
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| 160 | if(eFinal < 0.0 && verboseLevel > 0) { |
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| 161 | G4cout << "G4VHadronElastic WARNING Efinal= " << eFinal |
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| 162 | << " after scattering of " |
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| 163 | << aParticle->GetDefinition()->GetParticleName() |
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| 164 | << " p(GeV/c)= " << plab |
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| 165 | << " on " << theDef->GetParticleName() |
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| 166 | << G4endl; |
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| 167 | } |
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| 168 | theParticleChange.SetEnergyChange(0.0); |
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| 169 | nlv1 = G4LorentzVector(0.0,0.0,0.0,m1); |
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| 170 | |
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| 171 | } else { |
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| 172 | theParticleChange.SetMomentumChange(nlv1.vect().unit()); |
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| 173 | theParticleChange.SetEnergyChange(eFinal); |
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| 174 | } |
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| 175 | |
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| 176 | G4LorentzVector nlv0 = lv - nlv1; |
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| 177 | G4double erec = nlv0.e() - m2; |
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| 178 | if (verboseLevel > 1) { |
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| 179 | G4cout << "Recoil: " <<" m= " << m2 << " Erec(MeV)= " << erec |
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| 180 | << " 4-mom: " << nlv0 |
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| 181 | << G4endl; |
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| 182 | } |
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| 183 | |
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| 184 | if(erec > GetRecoilEnergyThreshold()) { |
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| 185 | G4DynamicParticle * aSec = new G4DynamicParticle(theDef, nlv0); |
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| 186 | theParticleChange.AddSecondary(aSec); |
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| 187 | } else if(erec > 0.0) { |
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| 188 | theParticleChange.SetLocalEnergyDeposit(erec); |
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| 189 | } |
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| 190 | |
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| 191 | return &theParticleChange; |
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| 192 | } |
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| 193 | |
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| 194 | // sample momentum transfer in the CMS system |
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| 195 | G4double |
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| 196 | G4VHadronElastic::SampleInvariantT(const G4ParticleDefinition* /*p*/, |
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| 197 | G4double /*ptot*/, |
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| 198 | G4int /*Z*/, G4int A) |
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| 199 | { |
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| 200 | static const G4double GeV2 = GeV*GeV; |
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| 201 | G4double tmax = 4.0*momentumCMS*momentumCMS/GeV2; |
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| 202 | G4double aa, bb, cc; |
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| 203 | G4double dd = 10.; |
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| 204 | G4Pow* p = G4Pow::GetInstance(); |
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| 205 | if (A <= 62) { |
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| 206 | bb = 14.5*p->Z23(A); |
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| 207 | aa = p->powZ(A, 1.63)/bb; |
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| 208 | cc = 1.4*p->Z13(A)/dd; |
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| 209 | } else { |
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| 210 | bb = 60.*p->Z13(A); |
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| 211 | aa = p->powZ(A, 1.33)/bb; |
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| 212 | cc = 0.4*p->powZ(A, 0.4)/dd; |
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| 213 | } |
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| 214 | G4double q1 = 1.0 - std::exp(-bb*tmax); |
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| 215 | G4double q2 = 1.0 - std::exp(-dd*tmax); |
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| 216 | G4double s1 = q1*aa; |
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| 217 | G4double s2 = q2*cc; |
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| 218 | if((s1 + s2)*G4UniformRand() < s2) { |
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| 219 | q1 = q2; |
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| 220 | bb = dd; |
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| 221 | } |
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| 222 | return -GeV2*std::log(1.0 - G4UniformRand()*q1)/bb; |
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| 223 | } |
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| 224 | |
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