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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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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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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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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // |
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28 | // =========================================================================== |
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29 | // GEANT4 class |
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30 | // |
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31 | // Class: G4IonParametrisedLossModel |
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32 | // |
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33 | // Base class: G4VEmModel (utils) |
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34 | // |
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35 | // Author: Anton Lechner (Anton.Lechner@cern.ch) |
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36 | // |
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37 | // First implementation: 10. 11. 2008 |
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38 | // |
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39 | // Modifications: 03. 02. 2009 - Bug fix iterators (AL) |
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40 | // 11. 03. 2009 - Introduced new table handler (G4IonDEDXHandler) |
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41 | // and modified method to add/remove tables |
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42 | // (tables are now built in initialisation phase), |
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43 | // Minor bug fix in ComputeDEDXPerVolume (AL) |
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44 | // 20. 11. 2009 - Added set-method for energy loss limit (AL) |
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45 | // |
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46 | // Class description: |
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47 | // Model for computing the energy loss of ions by employing a |
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48 | // parameterisation of dE/dx tables (default ICRU 73 tables). For |
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49 | // ion-material combinations and/or projectile energies not covered |
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50 | // by this model, the G4BraggIonModel and G4BetheBloch models are |
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51 | // employed. |
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52 | // |
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53 | // Comments: |
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54 | // |
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55 | // =========================================================================== |
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56 | |
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57 | |
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58 | inline G4double G4IonParametrisedLossModel::DeltaRayMeanEnergyTransferRate( |
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59 | const G4Material* material, |
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60 | const G4ParticleDefinition* particle, |
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61 | G4double kineticEnergy, |
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62 | G4double cutEnergy) { |
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63 | |
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64 | // ############## Mean energy transferred to delta-rays ################### |
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65 | // Computes the mean energy transfered to delta-rays per unit length, |
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66 | // considering only delta-rays with energies above the energy threshold |
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67 | // (energy cut) |
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68 | // |
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69 | // The mean energy transfer rate is derived by using the differential |
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70 | // cross section given in the references below. |
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71 | // |
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72 | // See Geant4 physics reference manual (version 9.1), section 9.1.3 |
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73 | // |
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74 | // Ref.: W.M. Yao et al, Jour. of Phys. G 33 (2006) 1. |
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75 | // B. Rossi, High energy particles, New York, NY: Prentice-Hall (1952). |
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76 | // |
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77 | // (Implementation adapted from G4BraggIonModel) |
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78 | |
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79 | |
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80 | // *** Variables: |
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81 | // kineticEnergy = kinetic energy of projectile |
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82 | // totEnergy = total energy of projectile, i.e. kinetic energy |
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83 | // plus rest energy (Mc^2) |
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84 | // betaSquared = beta of projectile squared, calculated as |
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85 | // beta^2 = 1 - 1 / (E/Mc^2)^2 |
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86 | // = T * ( E + Mc^2 ) / E^2 |
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87 | // where T = kineticEnergy, E = totEnergy |
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88 | // cutEnergy = energy threshold for secondary particle production |
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89 | // i.e. energy cut, below which energy transfered to |
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90 | // electrons is treated as continuous loss of projectile |
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91 | // maxKinEnergy = maximum energy transferable to secondary electrons |
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92 | // meanRate = mean kinetic energy of delta ray (per unit length) |
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93 | // (above cutEnergy) |
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94 | |
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95 | G4double meanRate = 0.0; |
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96 | |
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97 | G4double maxKinEnergy = MaxSecondaryEnergy(particle, kineticEnergy); |
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98 | |
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99 | if (cutEnergy < maxKinEnergy) { |
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100 | |
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101 | G4double totalEnergy = kineticEnergy + cacheMass; |
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102 | G4double betaSquared = kineticEnergy * |
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103 | (totalEnergy + cacheMass) / (totalEnergy * totalEnergy); |
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104 | |
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105 | G4double cutMaxEnergyRatio = cutEnergy / maxKinEnergy; |
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106 | |
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107 | meanRate = |
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108 | (- std::log(cutMaxEnergyRatio) - (1.0 - cutMaxEnergyRatio) * betaSquared) * |
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109 | twopi_mc2_rcl2 * |
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110 | (material->GetTotNbOfElectPerVolume()) / betaSquared; |
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111 | |
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112 | meanRate *= GetChargeSquareRatio(particle, material, kineticEnergy); |
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113 | } |
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114 | |
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115 | return meanRate; |
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116 | } |
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117 | |
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118 | |
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119 | inline |
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120 | G4double G4IonParametrisedLossModel::MaxSecondaryEnergy( |
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121 | const G4ParticleDefinition* particle, |
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122 | G4double kineticEnergy) { |
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123 | |
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124 | // ############## Maximum energy of secondaries ########################## |
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125 | // Function computes maximum energy of secondary electrons which are |
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126 | // released by an ion |
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127 | // |
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128 | // See Geant4 physics reference manual (version 9.1), section 9.1.1 |
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129 | // |
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130 | // Ref.: W.M. Yao et al, Jour. of Phys. G 33 (2006) 1. |
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131 | // C.Caso et al. (Part. Data Group), Europ. Phys. Jour. C 3 1 (1998). |
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132 | // B. Rossi, High energy particles, New York, NY: Prentice-Hall (1952). |
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133 | // |
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134 | // (Implementation adapted from G4BraggIonModel) |
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135 | |
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136 | if(particle != cacheParticle) UpdateCache(particle); |
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137 | |
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138 | G4double tau = kineticEnergy/cacheMass; |
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139 | G4double tmax = 2.0 * electron_mass_c2 * tau * (tau + 2.) / |
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140 | (1. + 2.0 * (tau + 1.) * cacheElecMassRatio + |
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141 | cacheElecMassRatio * cacheElecMassRatio); |
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142 | |
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143 | return tmax; |
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144 | } |
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145 | |
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146 | |
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147 | inline |
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148 | void G4IonParametrisedLossModel::UpdateCache( |
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149 | const G4ParticleDefinition* particle) { |
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150 | |
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151 | cacheParticle = particle; |
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152 | cacheMass = particle -> GetPDGMass(); |
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153 | cacheElecMassRatio = electron_mass_c2 / cacheMass; |
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154 | G4double q = particle -> GetPDGCharge() / eplus; |
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155 | cacheChargeSquare = q * q; |
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156 | } |
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157 | |
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158 | |
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159 | inline |
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160 | G4double G4IonParametrisedLossModel::GetChargeSquareRatio( |
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161 | const G4ParticleDefinition* particle, |
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162 | const G4Material* material, |
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163 | G4double kineticEnergy) { // Kinetic energy |
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164 | |
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165 | G4double chargeSquareRatio = corrections -> |
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166 | EffectiveChargeSquareRatio(particle, |
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167 | material, |
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168 | kineticEnergy); |
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169 | corrFactor = chargeSquareRatio * |
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170 | corrections -> EffectiveChargeCorrection(particle, |
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171 | material, |
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172 | kineticEnergy); |
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173 | return corrFactor; |
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174 | } |
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175 | |
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176 | |
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177 | inline |
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178 | G4double G4IonParametrisedLossModel::GetParticleCharge( |
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179 | const G4ParticleDefinition* particle, |
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180 | const G4Material* material, |
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181 | G4double kineticEnergy) { // Kinetic energy |
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182 | |
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183 | return corrections -> GetParticleCharge(particle, material, kineticEnergy); |
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184 | } |
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185 | |
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186 | |
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187 | inline |
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188 | LossTableList::iterator G4IonParametrisedLossModel::IsApplicable( |
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189 | const G4ParticleDefinition* particle, // Projectile (ion) |
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190 | const G4Material* material) { // Target material |
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191 | |
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192 | LossTableList::iterator iter = lossTableList.end(); |
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193 | LossTableList::iterator iterTables = lossTableList.begin(); |
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194 | LossTableList::iterator iterTables_end = lossTableList.end(); |
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195 | |
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196 | for(;iterTables != iterTables_end; iterTables++) { |
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197 | G4bool isApplicable = (*iterTables) -> |
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198 | IsApplicable(particle, material); |
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199 | if(isApplicable) { |
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200 | iter = iterTables; |
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201 | break; |
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202 | } |
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203 | } |
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204 | |
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205 | return iter; |
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206 | } |
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207 | |
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208 | |
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209 | inline |
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210 | void G4IonParametrisedLossModel::SetEnergyLossLimit( |
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211 | G4double ionEnergyLossLimit) { |
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212 | |
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213 | if(ionEnergyLossLimit > 0 && ionEnergyLossLimit <=1) { |
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214 | |
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215 | energyLossLimit = ionEnergyLossLimit; |
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216 | } |
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217 | } |
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