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 | // |
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27 | // $Id: G4RToEConvForGamma.cc,v 1.4 2006/06/29 19:30:24 gunter Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-02 $ |
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29 | // |
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30 | // |
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31 | // -------------------------------------------------------------- |
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32 | // GEANT 4 class implementation file/ History: |
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33 | // 5 Oct. 2002, H.Kuirashige : Structure created based on object model |
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34 | // -------------------------------------------------------------- |
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35 | |
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36 | #include "G4RToEConvForGamma.hh" |
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37 | #include "G4ParticleDefinition.hh" |
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38 | #include "G4ParticleTable.hh" |
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39 | #include "G4Material.hh" |
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40 | #include "G4PhysicsLogVector.hh" |
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41 | |
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42 | #include "G4ios.hh" |
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43 | |
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44 | G4RToEConvForGamma::G4RToEConvForGamma() : G4VRangeToEnergyConverter() |
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45 | { |
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46 | theParticle = G4ParticleTable::GetParticleTable()->FindParticle("gamma"); |
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47 | if (theParticle ==0) { |
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48 | #ifdef G4VERBOSE |
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49 | if (GetVerboseLevel()>0) { |
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50 | G4cout << " G4RToEConvForGamma::G4RToEConvForGamma() "; |
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51 | G4cout << " Gamma is not defined !!" << G4endl; |
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52 | } |
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53 | #endif |
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54 | } |
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55 | TotBin = 100; |
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56 | } |
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57 | |
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58 | G4RToEConvForGamma::~G4RToEConvForGamma() |
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59 | { |
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60 | } |
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61 | |
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62 | |
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63 | // *********************************************************************** |
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64 | // ******************* BuildAbsorptionLengthVector *********************** |
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65 | // *********************************************************************** |
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66 | void G4RToEConvForGamma::BuildAbsorptionLengthVector( |
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67 | const G4Material* aMaterial, |
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68 | G4double , |
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69 | G4double , |
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70 | G4RangeVector* absorptionLengthVector ) |
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71 | { |
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72 | // fill the absorption length vector for this material |
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73 | // absorption length is defined here as |
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74 | // |
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75 | // absorption length = 5./ macroscopic absorption cross section |
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76 | // |
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77 | const G4CrossSectionTable* aCrossSectionTable = (G4CrossSectionTable*)(theLossTable); |
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78 | const G4ElementVector* elementVector = aMaterial->GetElementVector(); |
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79 | const G4double* atomicNumDensityVector = aMaterial->GetAtomicNumDensityVector(); |
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80 | |
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81 | // fill absorption length vector |
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82 | G4int NumEl = aMaterial->GetNumberOfElements(); |
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83 | G4double absorptionLengthMax = 0.0; |
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84 | for (size_t ibin=0; ibin<size_t(TotBin); ibin++) { |
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85 | G4double lowEdgeEnergy = absorptionLengthVector->GetLowEdgeEnergy(ibin); |
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86 | |
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87 | G4double SIGMA = 0. ; |
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88 | |
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89 | for (size_t iel=0; iel<size_t(NumEl); iel++) { |
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90 | G4bool isOut; |
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91 | G4int IndEl = (*elementVector)[iel]->GetIndex(); |
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92 | SIGMA += atomicNumDensityVector[iel]* |
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93 | (*aCrossSectionTable)[IndEl]->GetValue(lowEdgeEnergy,isOut); |
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94 | } |
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95 | // absorption length=5./SIGMA |
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96 | absorptionLengthVector->PutValue(ibin, 5./SIGMA); |
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97 | if (absorptionLengthMax < 5./SIGMA ) absorptionLengthMax = 5./SIGMA; |
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98 | } |
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99 | } |
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100 | |
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101 | |
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102 | |
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103 | // *********************************************************************** |
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104 | // ********************** ComputeCrossSection **************************** |
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105 | // *********************************************************************** |
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106 | G4double G4RToEConvForGamma::ComputeCrossSection(G4double AtomicNumber, |
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107 | G4double KineticEnergy) const |
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108 | { |
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109 | // Compute the "absorption" cross section of the photon "absorption" |
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110 | // cross section means here the sum of the cross sections of the |
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111 | // pair production, Compton scattering and photoelectric processes |
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112 | static G4double Z; |
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113 | const G4double t1keV = 1.*keV; |
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114 | const G4double t200keV = 200.*keV; |
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115 | const G4double t100MeV = 100.*MeV; |
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116 | |
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117 | static G4double s200keV, s1keV; |
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118 | static G4double tmin, tlow; |
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119 | static G4double smin, slow; |
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120 | static G4double cmin, clow, chigh; |
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121 | // compute Z dependent quantities in the case of a new AtomicNumber |
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122 | if(std::abs(AtomicNumber-Z)>0.1) { |
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123 | Z = AtomicNumber; |
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124 | G4double Zsquare = Z*Z; |
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125 | G4double Zlog = std::log(Z); |
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126 | G4double Zlogsquare = Zlog*Zlog; |
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127 | |
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128 | s200keV = (0.2651-0.1501*Zlog+0.02283*Zlogsquare)*Zsquare; |
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129 | tmin = (0.552+218.5/Z+557.17/Zsquare)*MeV; |
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130 | smin = (0.01239+0.005585*Zlog-0.000923*Zlogsquare)*std::exp(1.5*Zlog); |
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131 | cmin=std::log(s200keV/smin)/(std::log(tmin/t200keV)*std::log(tmin/t200keV)); |
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132 | tlow = 0.2*std::exp(-7.355/std::sqrt(Z))*MeV; |
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133 | slow = s200keV*std::exp(0.042*Z*std::log(t200keV/tlow)*std::log(t200keV/tlow)); |
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134 | s1keV = 300.*Zsquare; |
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135 | clow =std::log(s1keV/slow)/std::log(tlow/t1keV); |
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136 | |
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137 | chigh=(7.55e-5-0.0542e-5*Z)*Zsquare*Z/std::log(t100MeV/tmin); |
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138 | } |
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139 | |
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140 | // calculate the cross section (using an approximate empirical formula) |
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141 | G4double s; |
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142 | if ( KineticEnergy<tlow ) { |
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143 | if(KineticEnergy<t1keV) s = slow*std::exp(clow*std::log(tlow/t1keV)); |
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144 | else s = slow*std::exp(clow*std::log(tlow/KineticEnergy)); |
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145 | |
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146 | } else if ( KineticEnergy<t200keV ) { |
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147 | s = s200keV |
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148 | * std::exp(0.042*Z*std::log(t200keV/KineticEnergy)*std::log(t200keV/KineticEnergy)); |
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149 | |
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150 | } else if( KineticEnergy<tmin ){ |
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151 | s = smin |
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152 | * std::exp(cmin*std::log(tmin/KineticEnergy)*std::log(tmin/KineticEnergy)); |
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153 | |
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154 | } else { |
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155 | s = smin + chigh*std::log(KineticEnergy/tmin); |
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156 | |
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157 | } |
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158 | return s * barn; |
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159 | } |
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160 | |
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