[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: G4PolarizedGammaConversionModel.cc,v 1.6 2007/11/01 17:32:34 schaelic Exp $ |
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| 27 | // GEANT4 tag $Name: $ |
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| 28 | // |
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| 29 | // ------------------------------------------------------------------- |
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| 30 | // |
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| 31 | // GEANT4 Class file |
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| 32 | // |
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| 33 | // |
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| 34 | // File name: G4PolarizedGammaConversionModel |
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| 35 | // |
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| 36 | // Author: Karim Laihem |
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| 37 | // |
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| 38 | // Creation date: 19.04.2005 |
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| 39 | // |
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| 40 | // Modifications: |
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| 41 | // 21-08-06 Modified to fit in g4.8.1 framework (A.Schaelicke) |
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| 42 | // 19-03-07 Add initialisation of crossSectionCalculator (VI) |
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| 43 | // |
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| 44 | // Class Description: |
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| 45 | // |
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| 46 | // Implementation of gamma convertion to e+e- in the field of a nucleus |
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| 47 | // including polarization transfer |
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| 48 | |
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| 49 | // ------------------------------------------------------------------- |
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| 50 | // |
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| 51 | |
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| 52 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 53 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 54 | |
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| 55 | #include "G4PolarizedGammaConversionModel.hh" |
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| 56 | #include "G4Electron.hh" |
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| 57 | #include "G4Positron.hh" |
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| 58 | #include "G4Gamma.hh" |
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| 59 | #include "Randomize.hh" |
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| 60 | #include "G4DataVector.hh" |
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| 61 | #include "G4PhysicsLogVector.hh" |
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| 62 | #include "G4ParticleChangeForGamma.hh" |
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| 63 | #include "G4PolarizedPairProductionCrossSection.hh" |
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| 64 | #include "G4PolarizationHelper.hh" |
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| 65 | |
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| 66 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 67 | |
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| 68 | |
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| 69 | G4PolarizedGammaConversionModel::G4PolarizedGammaConversionModel(const G4ParticleDefinition* pd, |
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| 70 | const G4String& nam) |
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| 71 | : G4BetheHeitlerModel(pd,nam), crossSectionCalculator(0) |
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| 72 | { |
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| 73 | } |
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| 74 | |
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| 75 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 76 | |
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| 77 | G4PolarizedGammaConversionModel::~G4PolarizedGammaConversionModel() |
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| 78 | { |
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| 79 | if (crossSectionCalculator) delete crossSectionCalculator; |
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| 80 | } |
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| 81 | |
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| 82 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 83 | |
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| 84 | void G4PolarizedGammaConversionModel::Initialise(const G4ParticleDefinition* pd, |
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| 85 | const G4DataVector& dv) |
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| 86 | { |
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| 87 | G4BetheHeitlerModel::Initialise(pd,dv); |
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| 88 | if (!crossSectionCalculator) |
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| 89 | crossSectionCalculator = new G4PolarizedPairProductionCrossSection(); |
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| 90 | } |
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| 91 | |
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| 92 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 93 | |
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| 94 | void G4PolarizedGammaConversionModel::SampleSecondaries(std::vector<G4DynamicParticle*>* vdp, |
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| 95 | const G4MaterialCutsCouple* couple, |
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| 96 | const G4DynamicParticle* dp, |
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| 97 | G4double tmin, |
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| 98 | G4double maxEnergy) |
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| 99 | { |
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| 100 | G4BetheHeitlerModel::SampleSecondaries(vdp, couple, dp, tmin, maxEnergy); |
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| 101 | |
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| 102 | if(vdp && vdp->size()>0) { |
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| 103 | G4double gamEnergy0 = dp->GetKineticEnergy(); |
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| 104 | G4double lepEnergy1 = (*vdp)[0]->GetKineticEnergy(); |
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| 105 | G4double sintheta = dp->GetMomentumDirection().cross((*vdp)[0]->GetMomentumDirection()).mag(); |
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| 106 | if (sintheta>1.) sintheta=1.; |
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| 107 | |
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| 108 | G4StokesVector beamPol = dp->GetPolarization(); |
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| 109 | beamPol.SetPhoton(); |
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| 110 | |
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| 111 | // determine interaction plane |
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| 112 | G4ThreeVector nInteractionFrame = |
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| 113 | G4PolarizationHelper::GetFrame(dp->GetMomentumDirection(), |
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| 114 | (*vdp)[0]->GetMomentumDirection()); |
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| 115 | |
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| 116 | // transform polarization into interaction frame |
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| 117 | beamPol.InvRotateAz(nInteractionFrame,dp->GetMomentumDirection()); |
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| 118 | |
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| 119 | // calulcate polarization transfer |
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| 120 | crossSectionCalculator->SetMaterial(GetCurrentElement()->GetN(), // number of nucleons |
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| 121 | GetCurrentElement()->GetZ(), |
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| 122 | GetCurrentElement()->GetfCoulomb()); |
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| 123 | crossSectionCalculator->Initialize(gamEnergy0, lepEnergy1, sintheta, |
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| 124 | beamPol, G4StokesVector::ZERO); |
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| 125 | |
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| 126 | // deterimine final state polarization |
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| 127 | G4StokesVector lep1Pol = crossSectionCalculator->GetPol2(); |
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| 128 | lep1Pol.RotateAz(nInteractionFrame,(*vdp)[0]->GetMomentumDirection()); |
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| 129 | (*vdp)[0]->SetPolarization(lep1Pol.p1(), |
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| 130 | lep1Pol.p2(), |
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| 131 | lep1Pol.p3()); |
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| 132 | |
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| 133 | size_t num = vdp->size(); |
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| 134 | if (num!=2) G4cout<<" WARNING "<<num<<" secondaries in polarized pairproduction not supported!\n"; |
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| 135 | for (size_t i =1; i<num; ++i) { |
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| 136 | G4StokesVector lep2Pol = crossSectionCalculator->GetPol3(); |
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| 137 | lep2Pol.RotateAz(nInteractionFrame,(*vdp)[i]->GetMomentumDirection()); |
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| 138 | (*vdp)[i]->SetPolarization(lep2Pol.p1(), |
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| 139 | lep2Pol.p2(), |
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| 140 | lep2Pol.p3()); |
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| 141 | |
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| 142 | } |
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| 143 | } |
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| 144 | } |
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| 145 | |
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| 146 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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