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24 | // ******************************************************************** |
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25 | // |
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26 | // $Id: G4eCoulombScatteringModel.hh,v 1.36 2008/08/04 08:49:09 vnivanch Exp $ |
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27 | // GEANT4 tag $Name: geant4-09-02-ref-02 $ |
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28 | // |
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29 | // ------------------------------------------------------------------- |
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30 | // |
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31 | // GEANT4 Class header file |
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32 | // |
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33 | // |
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34 | // File name: G4eCoulombScatteringModel |
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35 | // |
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36 | // Author: Vladimir Ivanchenko |
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37 | // |
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38 | // Creation date: 19.02.2006 |
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39 | // |
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40 | // Modifications: |
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41 | // 01.08.06 V.Ivanchenko extend upper limit of table to TeV and review the |
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42 | // logic of building - only elements from G4ElementTable |
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43 | // 08.08.06 V.Ivanchenko build internal table in ekin scale, introduce faclim |
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44 | // 19.08.06 V.Ivanchenko add inline function ScreeningParameter and |
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45 | // make some members protected |
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46 | // 09.10.07 V.Ivanchenko reorganized methods, add cut dependence in scattering off e- |
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47 | // 09.06.08 V.Ivanchenko add SelectIsotope and sampling of the recoil ion |
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48 | // |
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49 | // Class Description: |
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50 | // |
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51 | // Implementation of eCoulombScattering of pointlike charge particle |
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52 | // on Atomic Nucleus for interval of scattering anles in Lab system |
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53 | // thetaMin - ThetaMax, nucleus recoil is neglected. |
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54 | // The model based on analysis of J.M.Fernandez-Varea et al. |
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55 | // NIM B73(1993)447 originated from G.Wentzel Z.Phys. 40(1927)590 with |
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56 | // screening parameter from H.A.Bethe Phys. Rev. 89 (1953) 1256. |
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57 | // |
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58 | |
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59 | // ------------------------------------------------------------------- |
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60 | // |
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61 | |
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62 | #ifndef G4eCoulombScatteringModel_h |
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63 | #define G4eCoulombScatteringModel_h 1 |
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64 | |
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65 | #include "G4VEmModel.hh" |
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66 | #include "G4PhysicsTable.hh" |
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67 | #include "G4NistManager.hh" |
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68 | #include "globals.hh" |
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69 | |
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70 | class G4ParticleChangeForGamma; |
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71 | class G4ParticleDefinition; |
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72 | |
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73 | class G4eCoulombScatteringModel : public G4VEmModel |
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74 | { |
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75 | |
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76 | public: |
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77 | |
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78 | G4eCoulombScatteringModel(const G4String& nam = "eCoulombScattering"); |
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79 | |
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80 | virtual ~G4eCoulombScatteringModel(); |
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81 | |
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82 | virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&); |
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83 | |
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84 | virtual G4double ComputeCrossSectionPerAtom( |
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85 | const G4ParticleDefinition*, |
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86 | G4double kinEnergy, |
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87 | G4double Z, |
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88 | G4double A, |
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89 | G4double cut, |
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90 | G4double emax); |
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91 | |
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92 | virtual void SampleSecondaries(std::vector<G4DynamicParticle*>*, |
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93 | const G4MaterialCutsCouple*, |
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94 | const G4DynamicParticle*, |
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95 | G4double tmin, |
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96 | G4double maxEnergy); |
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97 | |
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98 | inline void SetRecoilThreshold(G4double eth); |
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99 | |
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100 | protected: |
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101 | |
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102 | G4double CrossSectionPerAtom(); |
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103 | |
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104 | G4double SampleCosineTheta(); |
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105 | |
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106 | inline void DefineMaterial(const G4MaterialCutsCouple*); |
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107 | |
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108 | inline void SetupParticle(const G4ParticleDefinition*); |
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109 | |
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110 | inline void SetupKinematic(G4double kinEnergy, G4double cut); |
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111 | |
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112 | inline void SetupTarget(G4double Z, G4double kinEnergy); |
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113 | |
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114 | private: |
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115 | |
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116 | void ComputeMaxElectronScattering(G4double cut); |
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117 | |
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118 | // hide assignment operator |
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119 | G4eCoulombScatteringModel & operator=(const G4eCoulombScatteringModel &right); |
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120 | G4eCoulombScatteringModel(const G4eCoulombScatteringModel&); |
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121 | |
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122 | protected: |
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123 | |
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124 | const G4ParticleDefinition* theProton; |
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125 | const G4ParticleDefinition* theElectron; |
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126 | const G4ParticleDefinition* thePositron; |
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127 | |
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128 | G4ParticleTable* theParticleTable; |
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129 | G4ParticleChangeForGamma* fParticleChange; |
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130 | G4NistManager* fNistManager; |
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131 | const G4DataVector* currentCuts; |
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132 | |
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133 | const G4MaterialCutsCouple* currentCouple; |
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134 | const G4Material* currentMaterial; |
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135 | const G4Element* currentElement; |
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136 | G4int currentMaterialIndex; |
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137 | |
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138 | G4double coeff; |
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139 | G4double constn; |
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140 | G4double cosThetaMin; |
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141 | G4double cosThetaMax; |
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142 | G4double cosTetMinNuc; |
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143 | G4double cosTetMaxNuc; |
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144 | G4double cosTetMaxNuc2; |
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145 | G4double cosTetMaxElec; |
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146 | G4double cosTetMaxElec2; |
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147 | G4double q2Limit; |
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148 | G4double recoilThreshold; |
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149 | G4double elecXSection; |
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150 | G4double nucXSection; |
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151 | G4double ecut; |
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152 | |
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153 | // projectile |
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154 | const G4ParticleDefinition* particle; |
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155 | |
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156 | G4double chargeSquare; |
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157 | G4double spin; |
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158 | G4double mass; |
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159 | G4double tkin; |
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160 | G4double mom2; |
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161 | G4double invbeta2; |
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162 | G4double etag; |
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163 | G4double lowEnergyLimit; |
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164 | |
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165 | // target |
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166 | G4double targetZ; |
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167 | G4double screenZ; |
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168 | G4double formfactA; |
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169 | G4int idxelm; |
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170 | |
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171 | private: |
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172 | |
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173 | G4double a0; |
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174 | G4double alpha2; |
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175 | G4double faclim; |
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176 | G4double FF[100]; |
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177 | |
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178 | G4bool isInitialised; |
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179 | }; |
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180 | |
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181 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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182 | |
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183 | inline |
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184 | void G4eCoulombScatteringModel::DefineMaterial(const G4MaterialCutsCouple* cup) |
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185 | { |
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186 | if(cup != currentCouple) { |
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187 | currentCouple = cup; |
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188 | currentMaterial = cup->GetMaterial(); |
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189 | currentMaterialIndex = currentCouple->GetIndex(); |
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190 | } |
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191 | } |
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192 | |
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193 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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194 | |
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195 | inline |
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196 | void G4eCoulombScatteringModel::SetupParticle(const G4ParticleDefinition* p) |
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197 | { |
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198 | // Initialise mass and charge |
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199 | if(p != particle) { |
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200 | particle = p; |
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201 | mass = particle->GetPDGMass(); |
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202 | spin = particle->GetPDGSpin(); |
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203 | G4double q = particle->GetPDGCharge()/eplus; |
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204 | chargeSquare = q*q; |
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205 | tkin = 0.0; |
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206 | lowEnergyLimit = keV*mass/electron_mass_c2; |
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207 | } |
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208 | } |
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209 | |
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210 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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211 | |
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212 | inline void G4eCoulombScatteringModel::SetupKinematic(G4double ekin, |
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213 | G4double cut) |
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214 | { |
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215 | if(ekin != tkin || ecut != cut) { |
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216 | tkin = ekin; |
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217 | mom2 = tkin*(tkin + 2.0*mass); |
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218 | invbeta2 = 1.0 + mass*mass/mom2; |
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219 | cosTetMinNuc = cosThetaMin; |
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220 | cosTetMaxNuc = cosThetaMax; |
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221 | if(ekin <= 10.*cut && mass < MeV && cosThetaMin < 1.0) { |
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222 | cosTetMinNuc = ekin*(cosThetaMin + 1.0)/(10.*cut) - 1.0; |
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223 | } |
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224 | ComputeMaxElectronScattering(cut); |
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225 | } |
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226 | } |
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227 | |
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228 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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229 | |
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230 | inline void G4eCoulombScatteringModel::SetupTarget(G4double Z, G4double e) |
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231 | { |
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232 | if(Z != targetZ || e != etag) { |
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233 | etag = e; |
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234 | targetZ = Z; |
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235 | G4int iz= G4int(Z); |
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236 | if(iz > 99) iz = 99; |
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237 | G4double x = fNistManager->GetZ13(iz); |
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238 | screenZ = a0*x*x/mom2; |
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239 | if(iz > 1) screenZ *=(1.13 + 3.76*invbeta2*Z*Z*chargeSquare*alpha2); |
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240 | //screenZ = a0*x*x*(1.13 + 3.76*Z*Z*chargeSquare*alpha2)/mom2; |
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241 | // A.V. Butkevich et al., NIM A 488 (2002) 282 |
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242 | formfactA = FF[iz]; |
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243 | if(formfactA == 0.0) { |
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244 | x = fNistManager->GetA27(iz); |
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245 | formfactA = constn*x*x; |
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246 | FF[iz] = formfactA; |
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247 | } |
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248 | formfactA *= mom2; |
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249 | cosTetMaxNuc2 = cosTetMaxNuc; |
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250 | if(particle == theProton && 1 == iz && cosTetMaxNuc2 < 0.0) { |
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251 | cosTetMaxNuc2 = 0.0; |
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252 | } |
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253 | /* |
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254 | G4double ee = 10.*eV*Z; |
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255 | if(1 == iz) ee *= 2.0; |
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256 | G4double z = std::min(cosTetMaxElec, 1.0 - std::max(ecut,ee)*amu_c2 |
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257 | *fNistManager->GetAtomicMassAmu(iz)/mom2); |
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258 | cosTetMaxElec2 = std::max(cosTetMaxNuc2, z); |
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259 | */ |
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260 | cosTetMaxElec2 = cosTetMaxElec; |
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261 | } |
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262 | } |
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263 | |
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264 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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265 | |
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266 | inline void G4eCoulombScatteringModel::SetRecoilThreshold(G4double eth) |
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267 | { |
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268 | recoilThreshold = eth; |
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269 | } |
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270 | |
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271 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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272 | |
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273 | #endif |
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