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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // GEANT4 tag $Name: geant4-09-03 $ |
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28 | // |
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29 | // |
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30 | // GEANT4 physics class: G4ElectroNuclearCrossSection -- header file |
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31 | // M.V. Kossov, ITEP(Moscow), 24-OCT-01 |
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32 | // The last update: M.V. Kossov, CERN/ITEP (Moscow) 25-Sept-03 |
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33 | // |
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34 | |
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35 | #ifndef G4ElectroNuclearCrossSection_h |
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36 | #define G4ElectroNuclearCrossSection_h 1 |
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37 | |
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38 | #include "G4VCrossSectionDataSet.hh" |
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39 | #include "G4DynamicParticle.hh" |
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40 | #include "G4Element.hh" |
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41 | #include "G4ParticleTable.hh" |
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42 | #include "G4NucleiProperties.hh" |
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43 | #include <vector> |
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44 | #include "Randomize.hh" |
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45 | #include "G4Electron.hh" |
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46 | #include "G4Positron.hh" |
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47 | |
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48 | class G4ElectroNuclearCrossSection : public G4VCrossSectionDataSet |
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49 | { |
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50 | public: |
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51 | |
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52 | G4ElectroNuclearCrossSection(); |
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53 | virtual ~G4ElectroNuclearCrossSection(); |
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54 | |
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55 | G4bool IsApplicable(const G4DynamicParticle* aParticle, const G4Element* ) |
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56 | { |
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57 | return IsZAApplicable(aParticle, 0., 0.); |
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58 | } |
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59 | |
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60 | G4bool IsZAApplicable(const G4DynamicParticle* aParticle, G4double /*ZZ*/, |
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61 | G4double /*AA*/) |
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62 | { |
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63 | G4bool result = false; |
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64 | if( aParticle->GetDefinition()==G4Electron::ElectronDefinition()) result = true; |
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65 | if( aParticle->GetDefinition()==G4Positron::PositronDefinition()) result = true; |
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66 | return result; |
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67 | } |
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68 | |
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69 | |
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70 | G4double GetCrossSection(const G4DynamicParticle* aParticle, |
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71 | const G4Element* anElement, G4double T=0.); |
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72 | |
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73 | G4double GetIsoZACrossSection(const G4DynamicParticle* aParticle, |
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74 | G4double ZZ, G4double AA, G4double T=0.); |
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75 | |
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76 | |
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77 | G4double GetEquivalentPhotonEnergy(); |
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78 | |
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79 | G4double GetVirtualFactor(G4double nu, G4double Q2); |
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80 | |
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81 | G4double GetEquivalentPhotonQ2(G4double nu); |
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82 | |
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83 | void BuildPhysicsTable(const G4ParticleDefinition&) {} |
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84 | |
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85 | void DumpPhysicsTable(const G4ParticleDefinition&) {} |
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86 | |
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87 | private: |
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88 | G4int GetFunctions(G4double a, G4double* x, G4double* y, G4double* z); |
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89 | //G4double LinearFit(G4double X, G4int N, const G4double* XN, const G4double* YN); |
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90 | G4double ThresholdEnergy(G4int Z, G4int N); |
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91 | G4double HighEnergyJ1(G4double lE); |
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92 | G4double HighEnergyJ2(G4double lE); |
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93 | G4double HighEnergyJ3(G4double lE); |
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94 | G4double SolveTheEquation(G4double f); |
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95 | G4double Fun(G4double x); |
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96 | G4double DFun(G4double x); |
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97 | |
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98 | // Body |
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99 | private: |
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100 | static G4int lastN; // The last N of calculated nucleus |
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101 | static G4int lastZ; // The last Z of calculated nucleus |
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102 | static G4int lastF; // Last used in the cross section TheFirstBin |
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103 | static G4double* lastJ1; // Pointer to the last array of the J1 function |
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104 | static G4double* lastJ2; // Pointer to the last array of the J2 function |
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105 | static G4double* lastJ3; // Pointer to the last array of the J3 function |
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106 | static G4int lastL; // Last used in the cross section TheLastBin |
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107 | static G4double lastE; // Last used in the cross section Energy |
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108 | static G4double lastTH; // Last value of the Energy Threshold |
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109 | static G4double lastSig; // Last value of the Cross Section |
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110 | static G4double lastG; // Last value of gamma=lnE-ln(me) |
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111 | static G4double lastH; // Last value of the High energy A-dependence |
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112 | |
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113 | static std::vector <G4double*> J1; // Vector of pointers to the J1 tabulated functions |
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114 | static std::vector <G4double*> J2; // Vector of pointers to the J2 tabulated functions |
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115 | static std::vector <G4double*> J3; // Vector of pointers to the J3 tabulated functions |
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116 | }; |
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117 | |
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118 | inline G4double G4ElectroNuclearCrossSection::DFun(G4double x)// Parametrization of the PhotoNucCS |
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119 | { |
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120 | static const G4double shd=1.0734; // HE PomShadowing(D) |
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121 | static const G4double poc=0.0375; // HE Pomeron coefficient |
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122 | static const G4double pos=16.5; // HE Pomeron shift |
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123 | static const G4double reg=.11; // HE Reggeon slope |
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124 | static const G4double mel=0.5109989; // Mass of an electron in MeV |
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125 | static const G4double lmel=std::log(mel); // Log of an electron mass |
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126 | G4double y=std::exp(x-lastG-lmel); // y for the x |
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127 | G4double flux=lastG*(2.-y*(2.-y))-1.; // flux factor |
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128 | return (poc*(x-pos)+shd*std::exp(-reg*x))*flux; |
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129 | } |
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130 | |
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131 | inline G4double G4ElectroNuclearCrossSection::Fun(G4double x) // Integrated PhoNuc cross section |
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132 | { |
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133 | G4double dlg1=lastG+lastG-1.; |
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134 | G4double lgoe=lastG/lastE; |
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135 | G4double HE2=HighEnergyJ2(x); |
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136 | return dlg1*HighEnergyJ1(x)-lgoe*(HE2+HE2-HighEnergyJ3(x)/lastE); |
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137 | } |
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138 | |
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139 | inline G4double G4ElectroNuclearCrossSection::HighEnergyJ1(G4double lEn) |
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140 | { |
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141 | static const G4double le=std::log(50000.); // std::log(E0) |
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142 | static const G4double le2=le*le; // std::log(E0)^2 |
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143 | static const G4double a=.0375; // a |
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144 | static const G4double ha=a*.5; // a/2 |
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145 | static const G4double ab=a*16.5; // a*b |
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146 | static const G4double d=0.11; // d |
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147 | static const G4double cd=1.0734/d; // c/d |
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148 | static const G4double ele=std::exp(-d*le); // E0^(-d) |
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149 | return ha*(lEn*lEn-le2)-ab*(lEn-le)-cd*(std::exp(-d*lEn)-ele); |
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150 | } |
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151 | |
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152 | inline G4double G4ElectroNuclearCrossSection::HighEnergyJ2(G4double lEn) |
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153 | { |
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154 | static const G4double e=50000.; // E0 |
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155 | static const G4double le=std::log(e); // std::log(E0) |
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156 | static const G4double le1=(le-1.)*e; // (std::log(E0)-1)*E0 |
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157 | static const G4double a=.0375; // a |
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158 | static const G4double ab=a*16.5; // a*b |
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159 | static const G4double d=1.-0.11; // 1-d |
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160 | static const G4double cd=1.0734/d; // c/(1-d) |
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161 | static const G4double ele=std::exp(d*le); // E0^(1-d) |
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162 | G4double En=std::exp(lEn); |
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163 | return a*((lEn-1.)*En-le1)-ab*(En-e)+cd*(std::exp(d*lEn)-ele); |
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164 | } |
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165 | |
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166 | inline G4double G4ElectroNuclearCrossSection::HighEnergyJ3(G4double lEn) |
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167 | { |
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168 | static const G4double e=50000.; // E0 |
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169 | static const G4double le=std::log(e); // std::log(E0) |
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170 | static const G4double e2=e*e; // E0^2 |
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171 | static const G4double leh=(le-.5)*e2; // (std::log(E0)-.5)*E0^2 |
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172 | static const G4double ha=.0375*.5; // a/2 |
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173 | static const G4double hab=ha*16.5; // a*b/2 |
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174 | static const G4double d=2.-.11; // 2-d |
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175 | static const G4double cd=1.0734/d; // c/(2-d) |
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176 | static const G4double ele=std::exp(d*le); // E0^(2-d) |
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177 | G4double lastE2=std::exp(lEn+lEn); |
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178 | return ha*((lEn-.5)*lastE2-leh)-hab*(lastE2-e2)+cd*(std::exp(d*lEn)-ele); |
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179 | } |
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180 | |
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181 | #endif |
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