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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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11 | // * Neither the authors of this software system, nor their employing * |
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13 | // * work make any representation or warranty, express or implied, * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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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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24 | // ******************************************************************** |
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25 | // |
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26 | // $Id: G4PEEffectModel.cc,v 1.6 2007/05/22 17:34:36 vnivanch Exp $ |
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27 | // GEANT4 tag $Name: $ |
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28 | // |
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29 | // ------------------------------------------------------------------- |
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30 | // |
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31 | // GEANT4 Class file |
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32 | // |
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33 | // |
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34 | // File name: G4PEEffectModel |
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35 | // |
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36 | // Author: Vladimir Ivanchenko on base of Michel Maire code |
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37 | // |
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38 | // Creation date: 21.03.2005 |
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39 | // |
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40 | // Modifications: |
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41 | // |
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42 | // 04.12.05 : SetProposedKineticEnergy(0.) for the killed photon (mma) |
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43 | // |
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44 | // Class Description: |
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45 | // |
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46 | // ------------------------------------------------------------------- |
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47 | // |
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48 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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49 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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50 | |
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51 | #include "G4PEEffectModel.hh" |
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52 | #include "G4Electron.hh" |
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53 | #include "G4Gamma.hh" |
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54 | #include "Randomize.hh" |
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55 | #include "G4DataVector.hh" |
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56 | #include "G4ParticleChangeForGamma.hh" |
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57 | |
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58 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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59 | |
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60 | using namespace std; |
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61 | |
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62 | G4PEEffectModel::G4PEEffectModel(const G4ParticleDefinition*, |
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63 | const G4String& nam) |
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64 | : G4VEmModel(nam),isInitialized(false) |
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65 | { |
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66 | theGamma = G4Gamma::Gamma(); |
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67 | theElectron = G4Electron::Electron(); |
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68 | } |
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69 | |
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70 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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71 | |
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72 | G4PEEffectModel::~G4PEEffectModel() |
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73 | { |
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74 | } |
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75 | |
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76 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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77 | |
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78 | void G4PEEffectModel::Initialise(const G4ParticleDefinition*, |
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79 | const G4DataVector&) |
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80 | { |
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81 | if (isInitialized) return; |
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82 | if (pParticleChange) |
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83 | fParticleChange = |
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84 | reinterpret_cast<G4ParticleChangeForGamma*>(pParticleChange); |
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85 | else |
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86 | fParticleChange = new G4ParticleChangeForGamma(); |
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87 | |
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88 | fminimalEnergy = 1.0*eV; |
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89 | } |
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90 | |
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91 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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92 | |
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93 | void G4PEEffectModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect, |
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94 | const G4MaterialCutsCouple* couple, |
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95 | const G4DynamicParticle* aDynamicPhoton, |
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96 | G4double, |
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97 | G4double) |
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98 | { |
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99 | const G4Material* aMaterial = couple->GetMaterial(); |
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100 | |
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101 | G4double energy = aDynamicPhoton->GetKineticEnergy(); |
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102 | G4ParticleMomentum PhotonDirection = aDynamicPhoton->GetMomentumDirection(); |
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103 | |
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104 | // select randomly one element constituing the material. |
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105 | const G4Element* anElement = SelectRandomAtom(aMaterial,theGamma,energy); |
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106 | |
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107 | // |
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108 | // Photo electron |
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109 | // |
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110 | |
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111 | // Select atomic shell |
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112 | G4int nShells = anElement->GetNbOfAtomicShells(); |
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113 | G4int i = 0; |
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114 | while ((i<nShells) && (energy<anElement->GetAtomicShell(i))) i++; |
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115 | |
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116 | // no shell available |
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117 | if (i == nShells) return; |
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118 | |
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119 | G4double bindingEnergy = anElement->GetAtomicShell(i); |
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120 | G4double ElecKineEnergy = energy - bindingEnergy; |
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121 | |
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122 | if (ElecKineEnergy > fminimalEnergy) |
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123 | { |
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124 | // direction of the photo electron |
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125 | // |
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126 | G4double cosTeta = ElecCosThetaDistribution(ElecKineEnergy); |
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127 | G4double sinTeta = sqrt(1.-cosTeta*cosTeta); |
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128 | G4double Phi = twopi * G4UniformRand(); |
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129 | G4double dirx = sinTeta*cos(Phi),diry = sinTeta*sin(Phi),dirz = cosTeta; |
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130 | G4ThreeVector ElecDirection(dirx,diry,dirz); |
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131 | ElecDirection.rotateUz(PhotonDirection); |
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132 | // |
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133 | G4DynamicParticle* aParticle = new G4DynamicParticle ( |
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134 | theElectron,ElecDirection, ElecKineEnergy); |
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135 | fvect->push_back(aParticle); |
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136 | } |
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137 | |
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138 | fParticleChange->SetProposedKineticEnergy(0.); |
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139 | fParticleChange->ProposeTrackStatus(fStopAndKill); |
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140 | fParticleChange->ProposeLocalEnergyDeposit(bindingEnergy); |
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141 | } |
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142 | |
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143 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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144 | |
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145 | G4double G4PEEffectModel::ElecCosThetaDistribution(G4double kineEnergy) |
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146 | { |
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147 | // Compute Theta distribution of the emitted electron, with respect to the |
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148 | // incident Gamma. |
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149 | // The Sauter-Gavrila distribution for the K-shell is used. |
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150 | // |
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151 | G4double costeta = 1.; |
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152 | G4double gamma = 1. + kineEnergy/electron_mass_c2; |
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153 | if (gamma > 5.) return costeta; |
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154 | G4double beta = sqrt(gamma*gamma-1.)/gamma; |
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155 | G4double b = 0.5*gamma*(gamma-1.)*(gamma-2); |
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156 | |
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157 | G4double rndm,term,greject,grejsup; |
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158 | if (gamma < 2.) grejsup = gamma*gamma*(1.+b-beta*b); |
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159 | else grejsup = gamma*gamma*(1.+b+beta*b); |
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160 | |
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161 | do { rndm = 1.-2*G4UniformRand(); |
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162 | costeta = (rndm+beta)/(rndm*beta+1.); |
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163 | term = 1.-beta*costeta; |
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164 | greject = (1.-costeta*costeta)*(1.+b*term)/(term*term); |
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165 | } while(greject < G4UniformRand()*grejsup); |
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166 | |
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167 | return costeta; |
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168 | } |
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169 | |
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170 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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