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 | // Author: Luciano Pandola |
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27 | // |
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28 | // History: |
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29 | // -------- |
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30 | // 02 Jul 2003 L.Pandola First implementation |
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31 | // 16 Mar 2004 L.Pandola Removed unnecessary calls to std::pow(a,b) |
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32 | |
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33 | #include "G4PenelopeAnnihilation.hh" |
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34 | #include "Randomize.hh" |
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35 | #include "G4UnitsTable.hh" |
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36 | #include "G4PhysicsTable.hh" |
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37 | #include "G4ParticleDefinition.hh" |
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38 | #include "G4VParticleChange.hh" |
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39 | #include "G4Gamma.hh" |
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40 | #include "G4Positron.hh" |
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41 | #include "G4Track.hh" |
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42 | #include "G4Step.hh" |
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43 | #include "G4PhysicsLogVector.hh" |
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44 | #include "G4ElementTable.hh" |
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45 | #include "G4Material.hh" |
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46 | #include "G4MaterialCutsCouple.hh" |
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47 | |
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48 | // constructor |
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49 | |
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50 | G4PenelopeAnnihilation::G4PenelopeAnnihilation(const G4String& processName) |
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51 | : G4VRestDiscreteProcess (processName), |
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52 | lowEnergyLimit(250*eV), |
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53 | highEnergyLimit(100*GeV), |
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54 | nBins(200), |
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55 | cutForLowEnergySecondaryPhotons(250.0*eV) |
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56 | { |
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57 | meanFreePathTable = 0; |
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58 | if (verboseLevel > 0) |
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59 | { |
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60 | G4cout << GetProcessName() << " is created " << G4endl |
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61 | << "Energy range: " |
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62 | << lowEnergyLimit / keV << " keV - " |
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63 | << highEnergyLimit / GeV << " GeV" |
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64 | << G4endl; |
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65 | } |
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66 | |
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67 | G4cout << G4endl; |
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68 | G4cout << "*******************************************************************************" << G4endl; |
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69 | G4cout << "*******************************************************************************" << G4endl; |
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70 | G4cout << " The class G4PenelopeAnnihilation is NOT SUPPORTED ANYMORE. " << G4endl; |
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71 | G4cout << " It will be REMOVED with the next major release of Geant4. " << G4endl; |
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72 | G4cout << " Please consult: https://twiki.cern.ch/twiki/bin/view/Geant4/LoweProcesses" << G4endl; |
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73 | G4cout << "*******************************************************************************" << G4endl; |
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74 | G4cout << "*******************************************************************************" << G4endl; |
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75 | G4cout << G4endl; |
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76 | } |
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77 | |
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78 | // destructor |
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79 | G4PenelopeAnnihilation::~G4PenelopeAnnihilation() |
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80 | { |
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81 | if (meanFreePathTable) { |
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82 | meanFreePathTable->clearAndDestroy(); |
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83 | delete meanFreePathTable; |
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84 | } |
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85 | } |
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86 | |
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87 | |
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88 | void G4PenelopeAnnihilation::BuildPhysicsTable(const G4ParticleDefinition& ) |
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89 | { |
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90 | G4double lowEdgeEnergy, value; |
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91 | G4PhysicsLogVector* dataVector; |
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92 | |
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93 | // Build mean free path table for the e+e- annihilation |
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94 | |
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95 | if (meanFreePathTable) { |
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96 | meanFreePathTable->clearAndDestroy(); delete meanFreePathTable;} |
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97 | |
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98 | meanFreePathTable = |
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99 | new G4PhysicsTable(G4Material::GetNumberOfMaterials()); |
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100 | const G4MaterialTable* theMaterialTable = G4Material::GetMaterialTable(); |
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101 | G4Material* material; |
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102 | |
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103 | for (size_t j=0;j<G4Material::GetNumberOfMaterials();j++) |
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104 | { |
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105 | //create physics vector then fill it .... |
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106 | dataVector = new G4PhysicsLogVector(lowEnergyLimit, |
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107 | highEnergyLimit,nBins); |
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108 | material = (*theMaterialTable)[j]; |
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109 | const G4ElementVector* theElementVector = material->GetElementVector(); |
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110 | const G4double* NbOfAtomsPerVolume = |
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111 | material->GetVecNbOfAtomsPerVolume(); |
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112 | for (G4int i=0;i<nBins;i++) |
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113 | { |
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114 | lowEdgeEnergy = dataVector->GetLowEdgeEnergy(i); |
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115 | G4double sigma=0.0 ; |
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116 | for (size_t elm=0;elm<material->GetNumberOfElements();elm++) |
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117 | { |
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118 | G4double Z = (*theElementVector)[elm]->GetZ(); |
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119 | sigma += NbOfAtomsPerVolume[elm] * Z * |
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120 | calculateCrossSectionPerElectron(lowEdgeEnergy); |
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121 | } |
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122 | if (sigma > DBL_MIN) |
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123 | { |
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124 | value = 1.0/sigma; |
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125 | } |
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126 | else |
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127 | { |
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128 | value = DBL_MAX; |
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129 | } |
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130 | dataVector->PutValue(i,value); |
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131 | } |
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132 | meanFreePathTable->insertAt(j,dataVector); |
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133 | } |
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134 | PrintInfoDefinition(); |
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135 | } |
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136 | |
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137 | G4double G4PenelopeAnnihilation::calculateCrossSectionPerElectron |
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138 | (G4double ene) |
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139 | { |
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140 | //Heitler dcs formula for annihilation with free electrons at rest |
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141 | G4double crossSection=0.0; |
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142 | G4double gamma = 1.0+std::max(ene,1.0*eV)/electron_mass_c2; |
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143 | G4double gamma2 = gamma*gamma; |
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144 | G4double f2 = gamma2-1.0; |
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145 | G4double f1 = std::sqrt(f2); |
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146 | G4double pielr2 = pi*classic_electr_radius*classic_electr_radius; |
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147 | crossSection = pielr2*((gamma2+4.0*gamma+1.0)*std::log(gamma+f1)/f2 |
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148 | - (gamma+3.0)/f1)/(gamma+1.0); |
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149 | return crossSection; |
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150 | } |
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151 | |
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152 | G4VParticleChange* G4PenelopeAnnihilation::PostStepDoIt(const G4Track& aTrack, |
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153 | const G4Step& ) |
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154 | { |
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155 | aParticleChange.Initialize(aTrack); |
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156 | |
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157 | const G4DynamicParticle* incidentPositron = aTrack.GetDynamicParticle(); |
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158 | G4double kineticEnergy = incidentPositron->GetKineticEnergy(); |
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159 | G4ParticleMomentum positronDirection = |
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160 | incidentPositron->GetMomentumDirection(); |
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161 | |
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162 | // Do not make anything if particle is stopped, the annihilation then |
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163 | // should be performed by the AtRestDoIt! |
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164 | if (aTrack.GetTrackStatus() == fStopButAlive) return &aParticleChange; |
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165 | |
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166 | //G4cout << "Sono nel PostStep" << G4endl; |
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167 | |
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168 | //Annihilation in flight |
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169 | G4double gamma = 1.0 + std::max(kineticEnergy,1.0*eV)/electron_mass_c2; |
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170 | G4double gamma21 = std::sqrt(gamma*gamma-1); |
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171 | G4double ani = 1.0+gamma; |
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172 | G4double chimin = 1.0/(ani+gamma21); |
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173 | G4double rchi = (1.0-chimin)/chimin; |
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174 | G4double gt0 = ani*ani-2.0; |
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175 | G4double epsilon=0.0, reject=0.0, test=0.0; |
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176 | do{ |
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177 | epsilon = chimin*std::pow(rchi,G4UniformRand()); |
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178 | reject = ani*ani*(1.0-epsilon)+2.0*gamma-(1.0/epsilon); |
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179 | test = G4UniformRand()*gt0-reject; |
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180 | }while(test>0); |
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181 | |
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182 | G4double totalAvailableEnergy = kineticEnergy + 2.0*electron_mass_c2; |
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183 | G4double photon1Energy = epsilon*totalAvailableEnergy; |
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184 | G4double photon2Energy = (1.0-epsilon)*totalAvailableEnergy; |
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185 | G4double cosTheta1 = (ani-1.0/epsilon)/gamma21; |
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186 | G4double cosTheta2 = (ani-1.0/(1.0-epsilon))/gamma21; |
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187 | |
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188 | aParticleChange.SetNumberOfSecondaries(2); |
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189 | G4double localEnergyDeposit = 0.; |
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190 | |
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191 | G4double sinTheta1 = std::sqrt(1.-cosTheta1*cosTheta1); |
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192 | G4double phi1 = twopi * G4UniformRand(); |
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193 | G4double dirx1 = sinTheta1 * std::cos(phi1); |
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194 | G4double diry1 = sinTheta1 * std::sin(phi1); |
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195 | G4double dirz1 = cosTheta1; |
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196 | |
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197 | G4double sinTheta2 = std::sqrt(1.-cosTheta2*cosTheta2); |
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198 | G4double phi2 = phi1+pi; |
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199 | G4double dirx2 = sinTheta2 * std::cos(phi2); |
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200 | G4double diry2 = sinTheta2 * std::sin(phi2); |
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201 | G4double dirz2 = cosTheta2; |
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202 | |
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203 | if (photon1Energy > cutForLowEnergySecondaryPhotons) { |
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204 | G4ThreeVector photon1Direction (dirx1,diry1,dirz1); |
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205 | photon1Direction.rotateUz(positronDirection); |
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206 | // create G4DynamicParticle object for the particle1 |
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207 | G4DynamicParticle* aParticle1= new G4DynamicParticle (G4Gamma::Gamma(), |
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208 | photon1Direction, |
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209 | photon1Energy); |
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210 | aParticleChange.AddSecondary(aParticle1); |
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211 | } |
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212 | else localEnergyDeposit += photon1Energy; |
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213 | |
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214 | if (photon2Energy > cutForLowEnergySecondaryPhotons) { |
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215 | G4ThreeVector photon2Direction(dirx2,diry2,dirz2); |
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216 | photon2Direction.rotateUz(positronDirection); |
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217 | // create G4DynamicParticle object for the particle2 |
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218 | G4DynamicParticle* aParticle2= new G4DynamicParticle (G4Gamma::Gamma(), |
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219 | photon2Direction, |
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220 | photon2Energy); |
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221 | aParticleChange.AddSecondary(aParticle2); |
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222 | } |
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223 | else localEnergyDeposit += photon2Energy; |
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224 | |
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225 | aParticleChange.ProposeLocalEnergyDeposit(localEnergyDeposit); |
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226 | |
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227 | aParticleChange.ProposeMomentumDirection( 0., 0., 0. ); |
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228 | aParticleChange.ProposeEnergy(0.); |
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229 | aParticleChange.ProposeTrackStatus(fStopAndKill); |
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230 | |
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231 | return &aParticleChange; |
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232 | } |
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233 | |
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234 | |
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235 | G4VParticleChange* G4PenelopeAnnihilation::AtRestDoIt(const G4Track& aTrack, |
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236 | const G4Step& ) |
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237 | { |
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238 | aParticleChange.Initialize(aTrack); |
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239 | aParticleChange.SetNumberOfSecondaries(2); |
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240 | G4double cosTheta = -1.0+2.0*G4UniformRand(); |
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241 | G4double sinTheta = std::sqrt(1.0-cosTheta*cosTheta); |
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242 | G4double phi = twopi*G4UniformRand(); |
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243 | //G4cout << "cosTheta: " << cosTheta << " sinTheta: " << sinTheta << G4endl; |
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244 | //G4cout << "phi: " << phi << G4endl; |
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245 | G4ThreeVector direction (sinTheta*std::cos(phi),sinTheta*std::sin(phi),cosTheta); |
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246 | aParticleChange.AddSecondary(new G4DynamicParticle (G4Gamma::Gamma(), |
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247 | direction, electron_mass_c2) ); |
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248 | aParticleChange.AddSecondary(new G4DynamicParticle (G4Gamma::Gamma(), |
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249 | -direction, electron_mass_c2) ); |
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250 | |
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251 | aParticleChange.ProposeLocalEnergyDeposit(0.); |
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252 | |
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253 | // Kill the incident positron |
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254 | // |
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255 | aParticleChange.ProposeTrackStatus(fStopAndKill); |
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256 | |
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257 | return &aParticleChange; |
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258 | } |
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259 | |
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260 | void G4PenelopeAnnihilation::PrintInfoDefinition() |
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261 | { |
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262 | G4String comments = "Total cross section from Heilter formula" |
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263 | "(annihilation into 2 photons)."; |
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264 | comments += "\n Gamma energies sampled according Heitler"; |
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265 | comments += "\n It can be used for positrons"; |
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266 | comments += " in the energy range [250eV,100GeV]."; |
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267 | G4cout << G4endl << GetProcessName() << ": " << comments |
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268 | << G4endl; |
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269 | } |
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270 | |
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271 | G4bool G4PenelopeAnnihilation::IsApplicable( |
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272 | const G4ParticleDefinition& particle) |
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273 | { |
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274 | return ( &particle == G4Positron::Positron() ); |
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275 | } |
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276 | |
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277 | |
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278 | G4double G4PenelopeAnnihilation::GetMeanFreePath(const G4Track& aTrack, |
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279 | G4double, |
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280 | G4ForceCondition*) |
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281 | { |
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282 | const G4DynamicParticle* incidentPositron = aTrack.GetDynamicParticle(); |
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283 | G4double kineticEnergy = incidentPositron->GetKineticEnergy(); |
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284 | const G4MaterialCutsCouple* couple = aTrack.GetMaterialCutsCouple(); |
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285 | const G4Material* material = couple->GetMaterial(); |
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286 | G4int materialIndex = material->GetIndex(); |
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287 | if (kineticEnergy<lowEnergyLimit) |
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288 | { |
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289 | kineticEnergy = lowEnergyLimit; |
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290 | } |
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291 | |
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292 | G4double meanFreePath; |
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293 | G4bool isOutRange ; |
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294 | |
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295 | if (kineticEnergy>highEnergyLimit) |
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296 | { |
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297 | meanFreePath = DBL_MAX; |
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298 | } |
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299 | else |
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300 | { |
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301 | meanFreePath = (*meanFreePathTable)(materialIndex)-> |
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302 | GetValue(kineticEnergy,isOutRange); |
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303 | } |
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304 | |
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305 | return meanFreePath; |
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306 | } |
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307 | |
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308 | G4double G4PenelopeAnnihilation::GetMeanLifeTime(const G4Track&, |
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309 | G4ForceCondition*) |
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310 | |
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311 | { |
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312 | return 0.0; |
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313 | } |
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