[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 | // |
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[1196] | 27 | // $Id: G4ChargeExchange.cc,v 1.16 2009/09/22 16:21:46 vnivanch Exp $ |
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[1340] | 28 | // GEANT4 tag $Name: geant4-09-03-ref-09 $ |
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[819] | 29 | // |
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| 30 | // |
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| 31 | // G4 Model: Charge and strangness exchange based on G4LightMedia model |
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| 32 | // 28 May 2006 V.Ivanchenko |
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| 33 | // |
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| 34 | // Modified: |
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| 35 | // 07-Jun-06 V.Ivanchenko fix problem of rotation of final state |
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| 36 | // 25-Jul-06 V.Ivanchenko add 19 MeV low energy, below which S-wave is sampled |
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| 37 | // |
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| 38 | |
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| 39 | #include "G4ChargeExchange.hh" |
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| 40 | #include "G4ParticleTable.hh" |
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| 41 | #include "G4ParticleDefinition.hh" |
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| 42 | #include "G4IonTable.hh" |
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| 43 | #include "Randomize.hh" |
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[962] | 44 | #include "G4NucleiProperties.hh" |
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[819] | 45 | |
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[962] | 46 | G4ChargeExchange::G4ChargeExchange() : G4HadronicInteraction("Charge Exchange") |
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[819] | 47 | { |
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| 48 | SetMinEnergy( 0.0*GeV ); |
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| 49 | SetMaxEnergy( 100.*TeV ); |
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| 50 | |
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[962] | 51 | lowEnergyRecoilLimit = 100.*keV; |
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| 52 | lowestEnergyLimit = 1.*MeV; |
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[819] | 53 | |
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| 54 | theProton = G4Proton::Proton(); |
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| 55 | theNeutron = G4Neutron::Neutron(); |
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| 56 | theAProton = G4AntiProton::AntiProton(); |
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| 57 | theANeutron = G4AntiNeutron::AntiNeutron(); |
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| 58 | thePiPlus = G4PionPlus::PionPlus(); |
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| 59 | thePiMinus = G4PionMinus::PionMinus(); |
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| 60 | thePiZero = G4PionZero::PionZero(); |
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| 61 | theKPlus = G4KaonPlus::KaonPlus(); |
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| 62 | theKMinus = G4KaonMinus::KaonMinus(); |
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| 63 | theK0S = G4KaonZeroShort::KaonZeroShort(); |
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| 64 | theK0L = G4KaonZeroLong::KaonZeroLong(); |
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| 65 | theL = G4Lambda::Lambda(); |
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| 66 | theAntiL = G4AntiLambda::AntiLambda(); |
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| 67 | theSPlus = G4SigmaPlus::SigmaPlus(); |
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| 68 | theASPlus = G4AntiSigmaPlus::AntiSigmaPlus(); |
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| 69 | theSMinus = G4SigmaMinus::SigmaMinus(); |
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| 70 | theASMinus = G4AntiSigmaMinus::AntiSigmaMinus(); |
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| 71 | theS0 = G4SigmaZero::SigmaZero(); |
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| 72 | theAS0 = G4AntiSigmaZero::AntiSigmaZero(); |
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| 73 | theXiMinus = G4XiMinus::XiMinus(); |
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| 74 | theXi0 = G4XiZero::XiZero(); |
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| 75 | theAXiMinus = G4AntiXiMinus::AntiXiMinus(); |
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| 76 | theAXi0 = G4AntiXiZero::AntiXiZero(); |
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| 77 | theOmega = G4OmegaMinus::OmegaMinus(); |
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| 78 | theAOmega = G4AntiOmegaMinus::AntiOmegaMinus(); |
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| 79 | theD = G4Deuteron::Deuteron(); |
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| 80 | theT = G4Triton::Triton(); |
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| 81 | theA = G4Alpha::Alpha(); |
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| 82 | theA = G4He3::He3(); |
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| 83 | } |
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| 84 | |
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| 85 | G4ChargeExchange::~G4ChargeExchange() |
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[962] | 86 | {} |
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[819] | 87 | |
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| 88 | G4HadFinalState* G4ChargeExchange::ApplyYourself( |
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| 89 | const G4HadProjectile& aTrack, G4Nucleus& targetNucleus) |
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| 90 | { |
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| 91 | theParticleChange.Clear(); |
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| 92 | const G4HadProjectile* aParticle = &aTrack; |
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| 93 | G4double ekin = aParticle->GetKineticEnergy(); |
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| 94 | |
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| 95 | G4double aTarget = targetNucleus.GetN(); |
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| 96 | G4double zTarget = targetNucleus.GetZ(); |
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| 97 | |
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| 98 | G4int Z = static_cast<G4int>(zTarget+0.5); |
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| 99 | G4int A = static_cast<G4int>(aTarget+0.5); |
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| 100 | |
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[962] | 101 | if(ekin <= lowestEnergyLimit || A < 3) { |
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[819] | 102 | theParticleChange.SetEnergyChange(ekin); |
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| 103 | theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit()); |
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| 104 | return &theParticleChange; |
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| 105 | } |
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| 106 | |
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| 107 | G4double plab = aParticle->GetTotalMomentum(); |
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| 108 | |
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| 109 | if (verboseLevel > 1) |
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| 110 | G4cout << "G4ChargeExchange::DoIt: Incident particle plab=" |
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| 111 | << plab/GeV << " GeV/c " |
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| 112 | << " ekin(MeV) = " << ekin/MeV << " " |
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| 113 | << aParticle->GetDefinition()->GetParticleName() << G4endl; |
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| 114 | |
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| 115 | // Scattered particle referred to axis of incident particle |
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| 116 | const G4ParticleDefinition* theParticle = aParticle->GetDefinition(); |
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| 117 | |
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| 118 | G4int N = A - Z; |
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| 119 | G4int projPDG = theParticle->GetPDGEncoding(); |
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| 120 | if (verboseLevel > 1) |
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| 121 | G4cout << "G4ChargeExchange for " << theParticle->GetParticleName() |
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| 122 | << " PDGcode= " << projPDG << " on nucleus Z= " << Z |
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| 123 | << " A= " << A << " N= " << N |
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| 124 | << G4endl; |
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| 125 | |
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| 126 | G4ParticleDefinition * theDef = 0; |
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| 127 | |
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[962] | 128 | G4double m2 = G4NucleiProperties::GetNuclearMass((G4double)A, (G4double)Z); |
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[819] | 129 | G4LorentzVector lv1 = aParticle->Get4Momentum(); |
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| 130 | G4LorentzVector lv0(0.0,0.0,0.0,m2); |
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| 131 | |
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| 132 | G4LorentzVector lv = lv0 + lv1; |
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| 133 | G4ThreeVector bst = lv.boostVector(); |
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| 134 | lv1.boost(-bst); |
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| 135 | lv0.boost(-bst); |
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| 136 | |
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| 137 | // Sample final particles |
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| 138 | G4bool theHyperon = false; |
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| 139 | G4ParticleDefinition* theRecoil = 0; |
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| 140 | G4ParticleDefinition* theSecondary = 0; |
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| 141 | |
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| 142 | if(theParticle == theProton) { |
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| 143 | theSecondary = theNeutron; |
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| 144 | Z++; |
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| 145 | } else if(theParticle == theNeutron) { |
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| 146 | theSecondary = theProton; |
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| 147 | Z--; |
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| 148 | } else if(theParticle == thePiPlus) { |
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| 149 | theSecondary = thePiZero; |
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| 150 | Z++; |
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| 151 | } else if(theParticle == thePiMinus) { |
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| 152 | theSecondary = thePiZero; |
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| 153 | Z--; |
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| 154 | } else if(theParticle == theKPlus) { |
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| 155 | if(G4UniformRand()<0.5) theSecondary = theK0S; |
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| 156 | else theSecondary = theK0L; |
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| 157 | Z++; |
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| 158 | } else if(theParticle == theKMinus) { |
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| 159 | if(G4UniformRand()<0.5) theSecondary = theK0S; |
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| 160 | else theSecondary = theK0L; |
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| 161 | Z--; |
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| 162 | } else if(theParticle == theK0S || theParticle == theK0L) { |
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| 163 | if(G4UniformRand()*aTarget < zTarget) { |
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| 164 | theSecondary = theKPlus; |
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| 165 | Z--; |
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| 166 | } else { |
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| 167 | theSecondary = theKMinus; |
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| 168 | Z++; |
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| 169 | } |
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| 170 | } else if(theParticle == theANeutron) { |
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| 171 | theSecondary = theAProton; |
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| 172 | Z++; |
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| 173 | } else if(theParticle == theAProton) { |
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| 174 | theSecondary = theANeutron; |
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| 175 | Z--; |
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| 176 | } else if(theParticle == theL) { |
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| 177 | G4double x = G4UniformRand(); |
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| 178 | if(G4UniformRand()*aTarget < zTarget) { |
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| 179 | if(x < 0.2) { |
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| 180 | theSecondary = theS0; |
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| 181 | } else if (x < 0.4) { |
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| 182 | theSecondary = theSPlus; |
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| 183 | Z--; |
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| 184 | } else if (x < 0.6) { |
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| 185 | theSecondary = theProton; |
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| 186 | theRecoil = theL; |
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| 187 | theHyperon = true; |
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| 188 | A--; |
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| 189 | } else if (x < 0.8) { |
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| 190 | theSecondary = theProton; |
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| 191 | theRecoil = theS0; |
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| 192 | theHyperon = true; |
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| 193 | A--; |
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| 194 | } else { |
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| 195 | theSecondary = theNeutron; |
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| 196 | theRecoil = theSPlus; |
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| 197 | theHyperon = true; |
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| 198 | A--; |
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| 199 | } |
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| 200 | } else { |
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| 201 | if(x < 0.2) { |
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| 202 | theSecondary = theS0; |
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| 203 | } else if (x < 0.4) { |
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| 204 | theSecondary = theSMinus; |
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| 205 | Z++; |
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| 206 | } else if (x < 0.6) { |
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| 207 | theSecondary = theNeutron; |
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| 208 | theRecoil = theL; |
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| 209 | A--; |
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| 210 | theHyperon = true; |
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| 211 | } else if (x < 0.8) { |
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| 212 | theSecondary = theNeutron; |
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| 213 | theRecoil = theS0; |
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| 214 | theHyperon = true; |
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| 215 | A--; |
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| 216 | } else { |
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| 217 | theSecondary = theProton; |
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| 218 | theRecoil = theSMinus; |
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| 219 | theHyperon = true; |
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| 220 | A--; |
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| 221 | } |
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| 222 | } |
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| 223 | } |
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| 224 | |
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| 225 | if (Z == 1 && A == 2) theDef = theD; |
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| 226 | else if (Z == 1 && A == 3) theDef = theT; |
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| 227 | else if (Z == 2 && A == 3) theDef = theHe3; |
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| 228 | else if (Z == 2 && A == 4) theDef = theA; |
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| 229 | else theDef = G4ParticleTable::GetParticleTable()->FindIon(Z,A,0,Z); |
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| 230 | |
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| 231 | G4double m11 = theSecondary->GetPDGMass(); |
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| 232 | G4double m21 = theDef->GetPDGMass(); |
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| 233 | if(theRecoil) m21 += theRecoil->GetPDGMass(); |
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| 234 | else theRecoil = theDef; |
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| 235 | |
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| 236 | G4double etot = lv0.e() + lv1.e(); |
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| 237 | |
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[962] | 238 | // kinematiacally impossible |
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| 239 | if(etot < m11 + m21) { |
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| 240 | theParticleChange.SetEnergyChange(ekin); |
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| 241 | theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit()); |
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| 242 | return &theParticleChange; |
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| 243 | } |
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| 244 | |
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[819] | 245 | G4ThreeVector p1 = lv1.vect(); |
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[962] | 246 | G4double e1 = 0.5*etot*(1.0 - (m21*m21 - m11*m11)/(etot*etot)); |
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[819] | 247 | // G4double e2 = etot - e1; |
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| 248 | G4double ptot = std::sqrt(e1*e1 - m11*m11); |
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| 249 | |
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| 250 | G4double tmax = 4.0*ptot*ptot; |
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[962] | 251 | G4double g2 = GeV*GeV; |
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[819] | 252 | |
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[962] | 253 | G4double t = g2*SampleT(tmax/g2,aTarget); |
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[819] | 254 | |
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| 255 | if(verboseLevel>1) |
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[962] | 256 | G4cout <<"## G4ChargeExchange t= " << t << " tmax= " << tmax |
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[819] | 257 | << " ptot= " << ptot << G4endl; |
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| 258 | |
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| 259 | // Sampling in CM system |
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| 260 | G4double phi = G4UniformRand()*twopi; |
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| 261 | G4double cost = 1. - 2.0*t/tmax; |
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[962] | 262 | if(std::abs(cost) > 1.0) cost = 1.0; |
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[819] | 263 | G4double sint = std::sqrt((1.0-cost)*(1.0+cost)); |
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| 264 | |
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[962] | 265 | //if (verboseLevel > 1) |
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| 266 | // G4cout << "cos(t)=" << cost << " std::sin(t)=" << sint << G4endl; |
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[819] | 267 | |
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| 268 | G4ThreeVector v1(sint*std::cos(phi),sint*std::sin(phi),cost); |
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| 269 | v1 *= ptot; |
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| 270 | G4LorentzVector nlv1(v1.x(),v1.y(),v1.z(),e1); |
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| 271 | G4LorentzVector nlv0 = lv0 + lv1 - nlv1; |
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| 272 | |
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| 273 | nlv0.boost(bst); |
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| 274 | nlv1.boost(bst); |
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| 275 | |
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| 276 | theParticleChange.SetStatusChange(stopAndKill); |
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[962] | 277 | theParticleChange.SetEnergyChange(0.0); |
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[819] | 278 | G4DynamicParticle * aSec = new G4DynamicParticle(theSecondary, nlv1); |
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| 279 | theParticleChange.AddSecondary(aSec); |
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| 280 | |
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| 281 | G4double erec = nlv0.e() - m21; |
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[962] | 282 | |
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| 283 | //G4cout << "erec= " <<erec << " Esec= " << aSec->GetKineticEnergy() << G4endl; |
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| 284 | |
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[819] | 285 | if(theHyperon) { |
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| 286 | theParticleChange.SetLocalEnergyDeposit(erec); |
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| 287 | aSec = new G4DynamicParticle(); |
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| 288 | aSec->SetDefinition(theRecoil); |
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| 289 | aSec->SetKineticEnergy(0.0); |
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[962] | 290 | } else if(erec > lowEnergyRecoilLimit) { |
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[819] | 291 | aSec = new G4DynamicParticle(theRecoil, nlv0); |
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| 292 | theParticleChange.AddSecondary(aSec); |
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| 293 | } else { |
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[962] | 294 | if(erec < 0.0) erec = 0.0; |
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[819] | 295 | theParticleChange.SetLocalEnergyDeposit(erec); |
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| 296 | } |
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| 297 | return &theParticleChange; |
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| 298 | } |
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[962] | 299 | |
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| 300 | G4double G4ChargeExchange::SampleT(G4double tmax, G4double A) |
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| 301 | { |
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| 302 | G4double aa, bb, cc, dd; |
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| 303 | if (A <= 62.) { |
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| 304 | aa = std::pow(A, 1.63); |
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| 305 | bb = 14.5*std::pow(A, 0.66); |
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| 306 | cc = 1.4*std::pow(A, 0.33); |
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| 307 | dd = 10.; |
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| 308 | } else { |
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| 309 | aa = std::pow(A, 1.33); |
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| 310 | bb = 60.*std::pow(A, 0.33); |
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| 311 | cc = 0.4*std::pow(A, 0.40); |
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| 312 | dd = 10.; |
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| 313 | } |
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[1196] | 314 | G4double x1 = (1.0 - std::exp(-tmax*bb))*aa/bb; |
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| 315 | G4double x2 = (1.0 - std::exp(-tmax*dd))*cc/dd; |
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[962] | 316 | |
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| 317 | G4double t; |
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| 318 | G4double y = bb; |
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| 319 | if(G4UniformRand()*(x1 + x2) < x2) y = dd; |
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| 320 | |
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| 321 | do {t = -std::log(G4UniformRand())/y;} while (t > tmax); |
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| 322 | |
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| 323 | return t; |
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| 324 | } |
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| 325 | |
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