1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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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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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: geant4-09-02 $ |
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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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