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 | // Implementation of formulas in analogy to NASA technical paper 3621 by |
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27 | // Tripathi, et al. |
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28 | // |
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29 | // 26-Dec-2006 Isotope dependence added by D. Wright |
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30 | // |
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31 | |
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32 | #include "G4TripathiCrossSection.hh" |
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33 | #include "G4ParticleTable.hh" |
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34 | #include "G4IonTable.hh" |
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35 | #include "G4HadTmpUtil.hh" |
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36 | |
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37 | G4TripathiCrossSection::G4TripathiCrossSection() |
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38 | { |
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39 | // G4cout <<"New G4TripathiCrossSection " << this << G4endl; |
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40 | } |
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41 | G4TripathiCrossSection::~G4TripathiCrossSection() |
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42 | {} |
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43 | |
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44 | G4double G4TripathiCrossSection:: |
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45 | GetIsoZACrossSection(const G4DynamicParticle* aPart, G4double ZZ, G4double AA, |
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46 | G4double /*temperature*/) |
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47 | { |
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48 | G4double result = 0.; |
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49 | |
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50 | const G4double targetAtomicNumber = AA; |
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51 | const G4double nTargetProtons = ZZ; |
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52 | |
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53 | const G4double kineticEnergy = aPart->GetKineticEnergy()/MeV; |
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54 | const G4double nProjProtons = aPart->GetDefinition()->GetPDGCharge(); |
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55 | const G4double projectileAtomicNumber = |
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56 | aPart->GetDefinition()->GetBaryonNumber(); |
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57 | |
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58 | const G4double nuleonRadius=1.1E-15; |
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59 | const G4double myNuleonRadius=1.36E-15; |
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60 | |
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61 | // needs target mass |
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62 | G4double targetMass = |
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63 | G4ParticleTable::GetParticleTable()->GetIonTable() |
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64 | ->GetIonMass(G4lrint(nTargetProtons), G4lrint(targetAtomicNumber)); |
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65 | G4LorentzVector pTarget(0,0,0,targetMass); |
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66 | G4LorentzVector pProjectile(aPart->Get4Momentum()); |
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67 | pTarget = pTarget+pProjectile; |
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68 | G4double E_cm = (pTarget.mag()-targetMass-pProjectile.m())/MeV; |
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69 | if(E_cm <= DBL_MIN) return result; |
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70 | // done |
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71 | G4double r_rms_p = 0.6 * myNuleonRadius * |
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72 | std::pow(projectileAtomicNumber, 1./3.); |
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73 | G4double r_rms_t = 0.6 * myNuleonRadius * |
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74 | std::pow(targetAtomicNumber, 1./3.); |
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75 | |
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76 | // done |
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77 | G4double r_p = 1.29*r_rms_p/nuleonRadius ; |
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78 | G4double r_t = 1.29*r_rms_t/nuleonRadius; |
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79 | |
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80 | // done |
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81 | G4double Radius = r_p + r_t + |
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82 | 1.2*(std::pow(targetAtomicNumber, 1./3.) + |
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83 | std::pow(projectileAtomicNumber, 1./3.))/std::pow(E_cm, 1./3.); |
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84 | |
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85 | //done |
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86 | G4double B = 1.44*nProjProtons*nTargetProtons/Radius; |
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87 | if(E_cm <= B) return result; |
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88 | // done |
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89 | G4double Energy = kineticEnergy/projectileAtomicNumber; |
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90 | |
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91 | // done |
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92 | // |
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93 | // Note that this correction to G4TripathiCrossSection is just to accurately |
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94 | // reflect Tripathi's algorithm. However, if you're using alpha |
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95 | // particles/protons consider using the more accurate |
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96 | // G4TripathiLightCrossSection, which Tripathi developed specifically for |
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97 | // light systems. |
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98 | // |
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99 | |
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100 | G4double D; |
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101 | if (nProjProtons==1 && projectileAtomicNumber==1) |
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102 | { |
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103 | D = 2.05; |
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104 | } |
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105 | else if (nProjProtons==2 && projectileAtomicNumber==4) |
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106 | { |
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107 | D = 2.77-(8.0E-3*targetAtomicNumber)+ |
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108 | (1.8E-5*targetAtomicNumber*targetAtomicNumber) |
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109 | - 0.8/(1+std::exp((250.-Energy)/75.)); |
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110 | } |
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111 | else |
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112 | { |
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113 | // |
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114 | // This is the original value used in the G4TripathiCrossSection |
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115 | // implementation, and was used for all projectile/target conditions. |
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116 | // I'm not touching this, although judging from Tripathi's paper, this is |
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117 | // valid for cases where the nucleon density changes little with A. |
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118 | // |
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119 | D = 1.75; |
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120 | } |
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121 | // done |
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122 | G4double C_E = D * (1-std::exp(-Energy/40.)) - |
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123 | 0.292*std::exp(-Energy/792.)*std::cos(0.229*std::pow(Energy, 0.453)); |
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124 | |
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125 | // done |
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126 | G4double S = std::pow(projectileAtomicNumber, 1./3.)* |
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127 | std::pow(targetAtomicNumber, 1./3.)/ |
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128 | (std::pow(projectileAtomicNumber, 1./3.) + |
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129 | std::pow(targetAtomicNumber, 1./3.)); |
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130 | |
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131 | // done |
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132 | G4double deltaE = 1.85*S + 0.16*S/std::pow(E_cm,1./3.) - C_E + |
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133 | 0.91*(targetAtomicNumber-2.*nTargetProtons)*nProjProtons/ |
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134 | (targetAtomicNumber*projectileAtomicNumber); |
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135 | |
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136 | // done |
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137 | result = pi * nuleonRadius*nuleonRadius * |
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138 | std::pow(( std::pow(targetAtomicNumber, 1./3.) + |
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139 | std::pow(projectileAtomicNumber, 1./3.) + deltaE),2.) * |
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140 | (1-B/E_cm); |
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141 | |
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142 | if(result < 0.) result = 0.; |
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143 | return result*m2; |
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144 | |
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145 | } |
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146 | |
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147 | |
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148 | G4double G4TripathiCrossSection:: |
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149 | GetCrossSection(const G4DynamicParticle* aPart, const G4Element* anEle, |
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150 | G4double temperature) |
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151 | { |
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152 | G4int nIso = anEle->GetNumberOfIsotopes(); |
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153 | G4double xsection = 0; |
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154 | |
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155 | if (nIso) { |
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156 | G4double sig; |
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157 | G4IsotopeVector* isoVector = anEle->GetIsotopeVector(); |
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158 | G4double* abundVector = anEle->GetRelativeAbundanceVector(); |
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159 | G4double ZZ; |
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160 | G4double AA; |
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161 | |
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162 | for (G4int i = 0; i < nIso; i++) { |
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163 | ZZ = G4double( (*isoVector)[i]->GetZ() ); |
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164 | AA = G4double( (*isoVector)[i]->GetN() ); |
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165 | sig = GetIsoZACrossSection(aPart, ZZ, AA, temperature); |
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166 | xsection += sig*abundVector[i]; |
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167 | } |
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168 | |
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169 | } else { |
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170 | xsection = |
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171 | GetIsoZACrossSection(aPart, anEle->GetZ(), anEle->GetN(), |
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172 | temperature); |
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173 | } |
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174 | |
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175 | return xsection; |
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176 | } |
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