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 | #include "G4AdjointComptonModel.hh" |
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27 | #include "G4AdjointCSManager.hh" |
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28 | |
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29 | |
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30 | #include "G4Integrator.hh" |
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31 | #include "G4TrackStatus.hh" |
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32 | #include "G4ParticleChange.hh" |
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33 | #include "G4AdjointElectron.hh" |
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34 | #include "G4AdjointGamma.hh" |
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35 | #include "G4Gamma.hh" |
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36 | |
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37 | |
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38 | //////////////////////////////////////////////////////////////////////////////// |
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39 | // |
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40 | G4AdjointComptonModel::G4AdjointComptonModel(): |
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41 | G4VEmAdjointModel("AdjointCompton") |
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42 | |
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43 | { SetApplyCutInRange(false); |
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44 | SetUseMatrix(true); |
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45 | SetUseMatrixPerElement(true); |
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46 | SetIsIonisation(false); |
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47 | SetUseOnlyOneMatrixForAllElements(true); |
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48 | theAdjEquivOfDirectPrimPartDef =G4AdjointGamma::AdjointGamma(); |
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49 | theAdjEquivOfDirectSecondPartDef=G4AdjointElectron::AdjointElectron(); |
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50 | theDirectPrimaryPartDef=G4Gamma::Gamma(); |
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51 | second_part_of_same_type=false; |
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52 | |
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53 | } |
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54 | //////////////////////////////////////////////////////////////////////////////// |
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55 | // |
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56 | G4AdjointComptonModel::~G4AdjointComptonModel() |
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57 | {;} |
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58 | //////////////////////////////////////////////////////////////////////////////// |
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59 | // |
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60 | void G4AdjointComptonModel::SampleSecondaries(const G4Track& aTrack, |
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61 | G4bool IsScatProjToProjCase, |
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62 | G4ParticleChange* fParticleChange) |
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63 | { |
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64 | |
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65 | |
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66 | //A recall of the compton scattering law is |
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67 | //Egamma2=Egamma1/(1+(Egamma1/E0_electron)(1.-cos_th)) |
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68 | //Therefore Egamma2_max= Egamma2(cos_th=1) = Egamma1 |
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69 | //Therefore Egamma2_min= Egamma2(cos_th=-1) = Egamma1/(1+2.(Egamma1/E0_electron)) |
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70 | |
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71 | |
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72 | const G4DynamicParticle* theAdjointPrimary =aTrack.GetDynamicParticle(); |
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73 | //DefineCurrentMaterial(aTrack->GetMaterialCutsCouple()); |
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74 | size_t ind= 0; |
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75 | |
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76 | |
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77 | |
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78 | |
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79 | //Elastic inverse scattering //not correct in all the cases |
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80 | //--------------------------------------------------------- |
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81 | G4double adjointPrimKinEnergy = theAdjointPrimary->GetKineticEnergy(); |
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82 | |
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83 | //G4cout<<adjointPrimKinEnergy<<std::endl; |
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84 | if (adjointPrimKinEnergy>HighEnergyLimit*0.999){ |
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85 | return; |
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86 | } |
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87 | |
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88 | //Sample secondary energy |
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89 | //----------------------- |
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90 | G4double gammaE1; |
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91 | |
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92 | gammaE1 = SampleAdjSecEnergyFromCSMatrix(ind, |
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93 | adjointPrimKinEnergy, |
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94 | IsScatProjToProjCase); |
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95 | |
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96 | |
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97 | //gammaE2 |
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98 | //----------- |
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99 | |
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100 | G4double gammaE2 = adjointPrimKinEnergy; |
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101 | if (!IsScatProjToProjCase) gammaE2 = gammaE1 - adjointPrimKinEnergy; |
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102 | |
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103 | |
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104 | |
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105 | |
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106 | |
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107 | |
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108 | //Cos th |
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109 | //------- |
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110 | // G4cout<<"Compton scattering "<<gammaE1<<'\t'<<gammaE2<<std::endl; |
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111 | G4double cos_th = 1.+ electron_mass_c2*(1./gammaE1 -1./gammaE2); |
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112 | if (!IsScatProjToProjCase) { |
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113 | G4double p_elec=theAdjointPrimary->GetTotalMomentum(); |
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114 | cos_th = (gammaE1 - gammaE2*cos_th)/p_elec; |
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115 | } |
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116 | G4double sin_th = 0.; |
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117 | if (std::abs(cos_th)>1){ |
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118 | //G4cout<<"Problem in compton scattering with cos_th "<<cos_th<<std::endl; |
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119 | if (cos_th>0) { |
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120 | cos_th=1.; |
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121 | } |
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122 | else cos_th=-1.; |
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123 | sin_th=0.; |
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124 | } |
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125 | else sin_th = std::sqrt(1.-cos_th*cos_th); |
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126 | |
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127 | |
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128 | |
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129 | |
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130 | //gamma0 momentum |
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131 | //-------------------- |
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132 | |
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133 | |
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134 | G4ThreeVector dir_parallel=theAdjointPrimary->GetMomentumDirection(); |
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135 | G4double phi =G4UniformRand()*2.*3.1415926; |
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136 | G4ThreeVector gammaMomentum1 = gammaE1*G4ThreeVector(std::cos(phi)*sin_th,std::sin(phi)*sin_th,cos_th); |
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137 | gammaMomentum1.rotateUz(dir_parallel); |
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138 | // G4cout<<gamma0Energy<<'\t'<<gamma0Momentum<<std::endl; |
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139 | |
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140 | |
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141 | //It is important to correct the weight of particles before adding the secondary |
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142 | //------------------------------------------------------------------------------ |
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143 | CorrectPostStepWeight(fParticleChange, aTrack.GetWeight(), adjointPrimKinEnergy,gammaE1); |
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144 | |
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145 | if (!IsScatProjToProjCase && CorrectWeightMode){ //kill the primary and add a secondary |
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146 | fParticleChange->ProposeTrackStatus(fStopAndKill); |
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147 | fParticleChange->AddSecondary(new G4DynamicParticle(theAdjEquivOfDirectPrimPartDef,gammaMomentum1)); |
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148 | //G4cout<<"gamma0Momentum "<<gamma0Momentum<<std::endl; |
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149 | } |
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150 | else { |
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151 | fParticleChange->ProposeEnergy(gammaE1); |
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152 | fParticleChange->ProposeMomentumDirection(gammaMomentum1.unit()); |
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153 | } |
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154 | |
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155 | |
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156 | } |
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157 | //////////////////////////////////////////////////////////////////////////////// |
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158 | // |
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159 | //The implementation here is correct for energy loss process, for the photoelectric and compton scattering the method should be redefine |
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160 | G4double G4AdjointComptonModel::DiffCrossSectionPerAtomPrimToSecond( |
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161 | G4double gamEnergy0, |
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162 | G4double kinEnergyElec, |
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163 | G4double Z, |
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164 | G4double A) |
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165 | { |
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166 | G4double gamEnergy1 = gamEnergy0 - kinEnergyElec; |
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167 | G4double dSigmadEprod=0.; |
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168 | if (gamEnergy1>0.) dSigmadEprod=DiffCrossSectionPerAtomPrimToScatPrim(gamEnergy0,gamEnergy1,Z,A); |
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169 | return dSigmadEprod; |
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170 | } |
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171 | |
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172 | |
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173 | //////////////////////////////////////////////////////////////////////////////// |
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174 | // |
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175 | G4double G4AdjointComptonModel::DiffCrossSectionPerAtomPrimToScatPrim( |
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176 | G4double gamEnergy0, |
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177 | G4double gamEnergy1, |
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178 | G4double Z, |
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179 | G4double ) |
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180 | { //Based on Klein Nishina formula |
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181 | //* In the forward case (see G4KleinNishinaModel) the cross section is parametrised while the secondaries are sampled from the |
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182 | // Klein Nishida differential cross section |
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183 | // The used diffrential cross section here is therefore the cross section multiplied by the normalidsed differential Klein Nishida cross section |
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184 | |
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185 | |
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186 | //Klein Nishida Cross Section |
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187 | //----------------------------- |
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188 | G4double epsilon = gamEnergy0 / electron_mass_c2 ; |
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189 | G4double one_plus_two_epsi =1.+2.*epsilon; |
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190 | G4double gamEnergy1_max = gamEnergy0; |
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191 | G4double gamEnergy1_min = gamEnergy0/one_plus_two_epsi; |
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192 | if (gamEnergy1 >gamEnergy1_max || gamEnergy1<gamEnergy1_min) { |
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193 | /*G4cout<<"the differential CS is null"<<std::endl; |
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194 | G4cout<<gamEnergy0<<std::endl; |
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195 | G4cout<<gamEnergy1<<std::endl; |
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196 | G4cout<<gamEnergy1_min<<std::endl;*/ |
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197 | return 0.; |
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198 | } |
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199 | |
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200 | |
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201 | G4double epsi2 = epsilon *epsilon ; |
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202 | G4double one_plus_two_epsi_2=one_plus_two_epsi*one_plus_two_epsi; |
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203 | |
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204 | |
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205 | G4double CS=std::log(one_plus_two_epsi)*(1.- 2.*(1.+epsilon)/epsi2); |
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206 | CS+=4./epsilon +0.5*(1.-1./one_plus_two_epsi_2); |
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207 | CS/=epsilon; |
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208 | //Note that the pi*re2*Z factor is neglected because it is suppresed when computing dCS_dE1/CS; |
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209 | // in the differential cross section |
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210 | |
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211 | |
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212 | //Klein Nishida Differential Cross Section |
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213 | //----------------------------------------- |
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214 | G4double epsilon1 = gamEnergy1 / electron_mass_c2 ; |
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215 | G4double v= epsilon1/epsilon; |
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216 | G4double term1 =1.+ 1./epsilon -1/epsilon1; |
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217 | G4double dCS_dE1= 1./v +v + term1*term1 -1.; |
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218 | dCS_dE1 *=1./epsilon/gamEnergy0; |
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219 | |
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220 | |
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221 | //Normalised to the CS used in G4 |
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222 | //------------------------------- |
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223 | |
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224 | G4double G4direct_CS = theDirectEMModel->ComputeCrossSectionPerAtom(G4Gamma::Gamma(), |
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225 | gamEnergy0, |
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226 | Z, 0., 0.,0.); |
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227 | |
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228 | dCS_dE1 *= G4direct_CS/CS; |
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229 | /* G4cout<<"the differential CS is not null"<<std::endl; |
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230 | G4cout<<gamEnergy0<<std::endl; |
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231 | G4cout<<gamEnergy1<<std::endl;*/ |
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232 | |
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233 | return dCS_dE1; |
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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 | G4double G4AdjointComptonModel::GetSecondAdjEnergyMaxForScatProjToProjCase(G4double PrimAdjEnergy) |
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240 | { G4double inv_e_max = 1./PrimAdjEnergy - 2./electron_mass_c2; |
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241 | G4double e_max = HighEnergyLimit; |
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242 | if (inv_e_max > 0. ) e_max=std::min(1./inv_e_max,HighEnergyLimit); |
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243 | return e_max; |
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244 | } |
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245 | //////////////////////////////////////////////////////////////////////////////// |
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246 | // |
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247 | G4double G4AdjointComptonModel::GetSecondAdjEnergyMinForProdToProjCase(G4double PrimAdjEnergy) |
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248 | { G4double half_e=PrimAdjEnergy/2.; |
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249 | G4double term=std::sqrt(half_e*(electron_mass_c2+half_e)); |
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250 | G4double emin=half_e+term; |
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251 | return emin; |
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252 | } |
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