1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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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: G4BoldyshevTripletModel.cc,v 1.2 2010/11/12 16:48:13 flongo Exp $ |
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27 | // GEANT4 tag $Name: geant4-09-04-ref-00 $ |
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28 | // |
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29 | // |
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30 | // Author: Gerardo Depaola & Francesco Longo |
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31 | // |
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32 | // History: |
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33 | // -------- |
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34 | // 23-06-2010 First implementation as model |
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35 | |
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36 | |
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37 | #include "G4BoldyshevTripletModel.hh" |
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38 | |
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39 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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40 | |
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41 | using namespace std; |
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42 | |
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43 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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44 | |
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45 | G4BoldyshevTripletModel::G4BoldyshevTripletModel(const G4ParticleDefinition*, |
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46 | const G4String& nam) |
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47 | :G4VEmModel(nam),smallEnergy(4.*MeV),isInitialised(false), |
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48 | crossSectionHandler(0),meanFreePathTable(0) |
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49 | { |
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50 | lowEnergyLimit = 4.0*electron_mass_c2; |
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51 | highEnergyLimit = 100 * GeV; |
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52 | SetHighEnergyLimit(highEnergyLimit); |
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53 | |
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54 | verboseLevel= 0; |
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55 | // Verbosity scale: |
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56 | // 0 = nothing |
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57 | // 1 = warning for energy non-conservation |
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58 | // 2 = details of energy budget |
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59 | // 3 = calculation of cross sections, file openings, sampling of atoms |
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60 | // 4 = entering in methods |
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61 | |
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62 | if(verboseLevel > 0) { |
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63 | G4cout << "Triplet Gamma conversion is constructed " << G4endl |
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64 | << "Energy range: " |
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65 | << lowEnergyLimit / MeV << " MeV - " |
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66 | << highEnergyLimit / GeV << " GeV" |
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67 | << G4endl; |
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68 | } |
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69 | } |
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70 | |
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71 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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72 | |
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73 | G4BoldyshevTripletModel::~G4BoldyshevTripletModel() |
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74 | { |
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75 | if (crossSectionHandler) delete crossSectionHandler; |
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76 | } |
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77 | |
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78 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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79 | |
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80 | void |
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81 | G4BoldyshevTripletModel::Initialise(const G4ParticleDefinition*, |
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82 | const G4DataVector&) |
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83 | { |
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84 | if (verboseLevel > 3) |
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85 | G4cout << "Calling G4BoldyshevTripletModel::Initialise()" << G4endl; |
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86 | |
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87 | if (crossSectionHandler) |
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88 | { |
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89 | crossSectionHandler->Clear(); |
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90 | delete crossSectionHandler; |
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91 | } |
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92 | |
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93 | // Read data tables for all materials |
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94 | |
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95 | crossSectionHandler = new G4CrossSectionHandler(); |
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96 | crossSectionHandler->Initialise(0,lowEnergyLimit,100.*GeV,400); |
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97 | G4String crossSectionFile = "tripdata/pp-trip-cs-"; // here only pair in electron field cs should be used |
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98 | crossSectionHandler->LoadData(crossSectionFile); |
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99 | |
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100 | // |
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101 | |
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102 | if (verboseLevel > 0) { |
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103 | G4cout << "Loaded cross section files for Livermore GammaConversion" << G4endl; |
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104 | G4cout << "To obtain the total cross section this should be used only " << G4endl |
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105 | << "in connection with G4NuclearGammaConversion " << G4endl; |
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106 | } |
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107 | |
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108 | if (verboseLevel > 0) { |
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109 | G4cout << "Livermore Electron Gamma Conversion model is initialized " << G4endl |
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110 | << "Energy range: " |
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111 | << LowEnergyLimit() / MeV << " MeV - " |
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112 | << HighEnergyLimit() / GeV << " GeV" |
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113 | << G4endl; |
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114 | } |
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115 | |
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116 | if(isInitialised) return; |
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117 | fParticleChange = GetParticleChangeForGamma(); |
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118 | isInitialised = true; |
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119 | } |
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120 | |
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121 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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122 | |
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123 | G4double |
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124 | G4BoldyshevTripletModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition*, |
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125 | G4double GammaEnergy, |
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126 | G4double Z, G4double, |
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127 | G4double, G4double) |
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128 | { |
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129 | if (verboseLevel > 3) { |
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130 | G4cout << "Calling ComputeCrossSectionPerAtom() of G4BoldyshevTripletModel" |
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131 | << G4endl; |
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132 | } |
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133 | if (GammaEnergy < lowEnergyLimit || GammaEnergy > highEnergyLimit) return 0; |
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134 | |
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135 | G4double cs = crossSectionHandler->FindValue(G4int(Z), GammaEnergy); |
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136 | return cs; |
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137 | } |
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138 | |
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139 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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140 | |
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141 | void G4BoldyshevTripletModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect, |
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142 | const G4MaterialCutsCouple* , |
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143 | const G4DynamicParticle* aDynamicGamma, |
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144 | G4double, |
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145 | G4double) |
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146 | { |
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147 | |
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148 | // The energies of the secondary particles are sampled using |
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149 | // a modified Wheeler-Lamb model (see PhysRevD 7 (1973), 26) |
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150 | |
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151 | if (verboseLevel > 3) |
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152 | G4cout << "Calling SampleSecondaries() of G4BoldyshevTripletModel" << G4endl; |
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153 | |
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154 | G4double photonEnergy = aDynamicGamma->GetKineticEnergy(); |
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155 | G4ParticleMomentum photonDirection = aDynamicGamma->GetMomentumDirection(); |
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156 | |
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157 | G4double epsilon ; |
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158 | G4double p0 = electron_mass_c2; |
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159 | |
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160 | G4double positronTotEnergy, electronTotEnergy, thetaEle, thetaPos; |
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161 | G4double ener_re=0., theta_re, phi_re, phi; |
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162 | |
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163 | // Calculo de theta - elecron de recoil |
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164 | |
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165 | G4double energyThreshold = sqrt(2.)*electron_mass_c2; // -> momentumThreshold_N = 1 |
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166 | energyThreshold = 1.1*electron_mass_c2; |
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167 | // G4cout << energyThreshold << G4endl; |
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168 | |
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169 | G4double momentumThreshold_c = sqrt(energyThreshold * energyThreshold - electron_mass_c2*electron_mass_c2); // momentun in MeV/c unit |
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170 | G4double momentumThreshold_N = momentumThreshold_c/electron_mass_c2; // momentun in mc unit |
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171 | |
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172 | // Calculation of recoil electron production |
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173 | |
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174 | G4double SigmaTot = (28./9.) * std::log ( 2.* photonEnergy / electron_mass_c2 ) - 218. / 27. ; |
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175 | G4double X_0 = 2. * ( sqrt(momentumThreshold_N*momentumThreshold_N + 1) -1 ); |
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176 | G4double SigmaQ = (82./27. - (14./9.) * log (X_0) + 4./15.*X_0 - 0.0348 * X_0 * X_0); |
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177 | G4double recoilProb = G4UniformRand(); |
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178 | //G4cout << "SIGMA TOT " << SigmaTot << " " << "SigmaQ " << SigmaQ << " " << SigmaQ/SigmaTot << " " << recoilProb << G4endl; |
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179 | |
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180 | if (recoilProb >= SigmaQ/SigmaTot) // create electron recoil |
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181 | { |
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182 | |
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183 | G4double cosThetaMax = ( ( energyThreshold - electron_mass_c2 ) / (momentumThreshold_c) + electron_mass_c2* |
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184 | ( energyThreshold + electron_mass_c2 ) / (photonEnergy*momentumThreshold_c) ); |
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185 | |
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186 | if (cosThetaMax > 1) G4cout << "ERRORE " << G4endl; |
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187 | |
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188 | G4double r1; |
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189 | G4double r2; |
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190 | G4double are, bre, loga, f1_re, greject, cost; |
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191 | |
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192 | do { |
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193 | r1 = G4UniformRand(); |
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194 | r2 = G4UniformRand(); |
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195 | // cost = (pow(4./enern,0.5*r1)) ; |
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196 | cost = pow(cosThetaMax,r1); |
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197 | theta_re = acos(cost); |
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198 | are = 1./(14.*cost*cost); |
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199 | bre = (1.-5.*cost*cost)/(2.*cost); |
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200 | loga = log((1.+ cost)/(1.- cost)); |
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201 | f1_re = 1. - bre*loga; |
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202 | |
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203 | if ( theta_re >= 4.47*CLHEP::pi/180.) |
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204 | { |
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205 | greject = are*f1_re; |
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206 | } else { |
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207 | greject = 1. ; |
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208 | } |
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209 | } while(greject < r2); |
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210 | |
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211 | // Calculo de phi - elecron de recoil |
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212 | |
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213 | G4double r3, r4, rt; |
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214 | |
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215 | do { |
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216 | |
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217 | r3 = G4UniformRand(); |
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218 | r4 = G4UniformRand(); |
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219 | phi_re = twopi*r3 ; |
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220 | G4double sint2 = 1. - cost*cost ; |
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221 | G4double fp = 1. - sint2*loga/(2.*cost) ; |
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222 | rt = (1.-cos(2.*phi_re)*fp/f1_re)/(2.*pi) ; |
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223 | |
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224 | } while(rt < r4); |
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225 | |
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226 | // Calculo de la energia - elecron de recoil - relacion momento maximo <-> angulo |
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227 | |
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228 | G4double S = electron_mass_c2*(2.* photonEnergy + electron_mass_c2); |
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229 | G4double D2 = 4.*S * electron_mass_c2*electron_mass_c2 |
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230 | + (S - electron_mass_c2*electron_mass_c2) |
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231 | *(S - electron_mass_c2*electron_mass_c2)*sin(theta_re)*sin(theta_re); |
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232 | ener_re = electron_mass_c2 * (S + electron_mass_c2*electron_mass_c2)/sqrt(D2); |
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233 | |
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234 | // G4cout << "electron de retroceso " << ener_re << " " << theta_re << " " << phi_re << G4endl; |
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235 | |
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236 | // Recoil electron creation |
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237 | G4double dxEle_re=sin(theta_re)*std::cos(phi_re),dyEle_re=sin(theta_re)*std::sin(phi_re), dzEle_re=cos(theta_re); |
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238 | |
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239 | G4double electronRKineEnergy = std::max(0.,ener_re - electron_mass_c2) ; |
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240 | |
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241 | G4ThreeVector electronRDirection (dxEle_re, dyEle_re, dzEle_re); |
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242 | electronRDirection.rotateUz(photonDirection); |
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243 | |
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244 | G4DynamicParticle* particle3 = new G4DynamicParticle (G4Electron::Electron(), |
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245 | electronRDirection, |
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246 | electronRKineEnergy); |
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247 | fvect->push_back(particle3); |
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248 | |
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249 | } |
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250 | else |
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251 | { |
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252 | // deposito la energia ener_re - electron_mass_c2 |
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253 | // G4cout << "electron de retroceso " << ener_re << G4endl; |
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254 | fParticleChange->ProposeLocalEnergyDeposit(ener_re - electron_mass_c2); |
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255 | } |
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256 | |
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257 | // Depaola (2004) suggested distribution for e+e- energy |
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258 | |
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259 | // G4double t = 0.5*asinh(momentumThreshold_N); |
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260 | G4double t = 0.5*log(momentumThreshold_N + sqrt(momentumThreshold_N*momentumThreshold_N+1)); |
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261 | |
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262 | G4double J1 = 0.5*(t*cosh(t)/sinh(t) - log(2.*sinh(t))); |
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263 | G4double J2 = (-2./3.)*log(2.*sinh(t)) + t*cosh(t)/sinh(t) + (sinh(t)-t*pow(cosh(t),3))/(3.*pow(sinh(t),2)); |
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264 | G4double b = 2.*(J2-J1)/J1; |
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265 | |
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266 | G4double n = 1 - b/6.; |
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267 | G4double re=0.; |
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268 | re = G4UniformRand(); |
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269 | G4double a = 0.; |
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270 | G4double b1 = 16. - 3.*b - 36.*b*re*n + 36.*b*pow(re,2.)*pow(n,2.) + |
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271 | 6.*pow(b,2.)*re*n; |
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272 | a = pow((b1/b),0.5); |
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273 | G4double c1 = (-6. + 12.*re*n + b + 2*a)*pow(b,2.); |
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274 | epsilon = (pow(c1,1./3.))/(2.*b) + (b-4.)/(2.*pow(c1,1./3.))+0.5; |
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275 | |
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276 | G4double photonEnergy1 = photonEnergy - ener_re ; // resto al foton la energia del electron de retro. |
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277 | positronTotEnergy = epsilon*photonEnergy1; |
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278 | electronTotEnergy = photonEnergy1 - positronTotEnergy; // temporarly |
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279 | |
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280 | G4double momento_e = sqrt(electronTotEnergy*electronTotEnergy - |
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281 | electron_mass_c2*electron_mass_c2) ; |
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282 | G4double momento_p = sqrt(positronTotEnergy*positronTotEnergy - |
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283 | electron_mass_c2*electron_mass_c2) ; |
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284 | |
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285 | thetaEle = acos((sqrt(p0*p0/(momento_e*momento_e) +1.)- p0/momento_e)) ; |
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286 | thetaPos = acos((sqrt(p0*p0/(momento_p*momento_p) +1.)- p0/momento_p)) ; |
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287 | phi = twopi * G4UniformRand(); |
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288 | |
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289 | G4double dxEle= std::sin(thetaEle)*std::cos(phi),dyEle= std::sin(thetaEle)*std::sin(phi),dzEle=std::cos(thetaEle); |
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290 | G4double dxPos=-std::sin(thetaPos)*std::cos(phi),dyPos=-std::sin(thetaPos)*std::sin(phi),dzPos=std::cos(thetaPos); |
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291 | |
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292 | |
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293 | // Kinematics of the created pair: |
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294 | // the electron and positron are assumed to have a symetric angular |
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295 | // distribution with respect to the Z axis along the parent photon |
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296 | |
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297 | G4double electronKineEnergy = std::max(0.,electronTotEnergy - electron_mass_c2) ; |
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298 | |
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299 | // SI - The range test has been removed wrt original G4LowEnergyGammaconversion class |
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300 | |
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301 | G4ThreeVector electronDirection (dxEle, dyEle, dzEle); |
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302 | electronDirection.rotateUz(photonDirection); |
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303 | |
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304 | G4DynamicParticle* particle1 = new G4DynamicParticle (G4Electron::Electron(), |
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305 | electronDirection, |
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306 | electronKineEnergy); |
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307 | |
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308 | // The e+ is always created (even with kinetic energy = 0) for further annihilation |
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309 | G4double positronKineEnergy = std::max(0.,positronTotEnergy - electron_mass_c2) ; |
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310 | |
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311 | // SI - The range test has been removed wrt original G4LowEnergyGammaconversion class |
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312 | |
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313 | G4ThreeVector positronDirection (dxPos, dyPos, dzPos); |
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314 | positronDirection.rotateUz(photonDirection); |
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315 | |
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316 | // Create G4DynamicParticle object for the particle2 |
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317 | G4DynamicParticle* particle2 = new G4DynamicParticle(G4Positron::Positron(), |
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318 | positronDirection, positronKineEnergy); |
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319 | // Fill output vector |
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320 | |
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321 | |
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322 | fvect->push_back(particle1); |
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323 | fvect->push_back(particle2); |
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324 | |
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325 | |
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326 | |
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327 | |
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328 | // kill incident photon |
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329 | fParticleChange->SetProposedKineticEnergy(0.); |
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330 | fParticleChange->ProposeTrackStatus(fStopAndKill); |
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331 | |
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332 | } |
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333 | |
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334 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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335 | |
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336 | |
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337 | |
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338 | |
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