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24 | // ******************************************************************** |
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25 | // |
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26 | // $Id: G4CoulombScatteringModel.cc,v 1.29 2007/11/09 11:45:45 vnivanch Exp $ |
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27 | // GEANT4 tag $Name: geant4-09-01-patch-02 $ |
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28 | // |
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29 | // ------------------------------------------------------------------- |
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30 | // |
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31 | // GEANT4 Class file |
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32 | // |
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33 | // |
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34 | // File name: G4CoulombScatteringModel |
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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: 22.08.2005 |
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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 | // 19.10.06 V.Ivanchenko use inheritance from G4eCoulombScatteringModel |
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45 | // 09.10.07 V.Ivanchenko reorganized methods, add cut dependence in scattering off e- |
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46 | // |
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47 | // Class Description: |
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48 | // |
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49 | // ------------------------------------------------------------------- |
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50 | // |
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51 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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52 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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53 | |
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54 | #include "G4CoulombScatteringModel.hh" |
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55 | #include "Randomize.hh" |
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56 | #include "G4ParticleChangeForGamma.hh" |
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57 | #include "G4NistManager.hh" |
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58 | #include "G4ParticleTable.hh" |
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59 | #include "G4IonTable.hh" |
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60 | #include "G4Proton.hh" |
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61 | |
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62 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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63 | |
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64 | using namespace std; |
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65 | |
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66 | G4CoulombScatteringModel::G4CoulombScatteringModel( |
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67 | G4double thetaMin, G4double thetaMax, G4bool build, |
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68 | G4double tlim, const G4String& nam) |
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69 | : G4eCoulombScatteringModel(thetaMin,thetaMax,build,tlim,nam) |
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70 | { |
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71 | theMatManager = G4NistManager::Instance(); |
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72 | theParticleTable = G4ParticleTable::GetParticleTable(); |
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73 | } |
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74 | |
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75 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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76 | |
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77 | G4CoulombScatteringModel::~G4CoulombScatteringModel() |
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78 | {} |
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79 | |
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80 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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81 | |
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82 | G4double G4CoulombScatteringModel::ComputeCrossSectionPerAtom( |
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83 | const G4ParticleDefinition* p, |
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84 | G4double kinEnergy, |
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85 | G4double Z, |
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86 | G4double A, |
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87 | G4double cutEnergy, |
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88 | G4double) |
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89 | { |
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90 | if(p == particle && kinEnergy == tkin && Z == targetZ && |
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91 | A == targetA && cutEnergy == ecut) return nucXSection; |
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92 | |
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93 | // Lab system |
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94 | G4double ekin = std::max(keV, kinEnergy); |
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95 | nucXSection = ComputeElectronXSectionPerAtom(p,ekin,Z,A,cutEnergy); |
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96 | |
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97 | // CM system |
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98 | G4int iz = G4int(Z); |
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99 | G4double m1 = theMatManager->GetAtomicMassAmu(iz)*amu_c2; |
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100 | G4double etot = tkin + mass; |
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101 | G4double ptot = sqrt(mom2); |
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102 | G4double bet = ptot/(etot + m1); |
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103 | G4double gam = 1.0/sqrt((1.0 - bet)*(1.0 + bet)); |
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104 | G4double momCM= gam*(ptot - bet*etot); |
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105 | |
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106 | // G4cout << "ptot= " << ptot << " etot= " << etot << " beta= " |
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107 | // << bet << " gam= " << gam << " Z= " << Z << " A= " << A << G4endl; |
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108 | // G4cout << " CM. mom= " << momCM << " m= " << m |
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109 | // << " m1= " << m1 << " iz= " << iz <<G4endl; |
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110 | |
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111 | G4double momCM2 = momCM*momCM; |
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112 | cosTetMaxNuc = std::max(cosThetaMax, 1.0 - 0.5*q2Limit/momCM2); |
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113 | if(1.5 > targetA && p == theProton && cosTetMaxNuc < 0.0) cosTetMaxNuc = 0.0; |
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114 | //G4cout << " ctmax= " << cosTetMaxNuc |
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115 | //<< " ctmin= " << cosThetaMin << G4endl; |
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116 | |
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117 | // Cross section in CM system |
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118 | if(cosTetMaxNuc < cosThetaMin) { |
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119 | G4double effmass = mass*m1/(mass + m1); |
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120 | G4double x1 = 1.0 - cosThetaMin; |
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121 | G4double x2 = 1.0 - cosTetMaxNuc; |
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122 | G4double z1 = x1 + screenZ; |
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123 | G4double z2 = x2 + screenZ; |
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124 | G4double d = 1.0/formfactA; |
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125 | G4double zn1= x1 + d; |
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126 | G4double zn2= x2 + d; |
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127 | nucXSection += coeff*Z*Z*chargeSquare*(1.0 + effmass*effmass/momCM2) |
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128 | *(1./z1 - 1./z2 + 1./zn1 - 1./zn2 + |
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129 | 2.0*formfactA*std::log(z1*zn2/(z2*zn1)))/momCM2; |
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130 | //G4cout << "XS: x1= " << x1 << " x2= " << x2 |
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131 | //<< " cross= " << cross << G4endl; |
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132 | //G4cout << "momCM2= " << momCM2 << " invbeta2= " << invbeta2 |
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133 | // << " coeff= " << coeff << G4endl; |
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134 | } |
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135 | if(nucXSection < 0.0) nucXSection = 0.0; |
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136 | return nucXSection; |
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137 | } |
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138 | |
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139 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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140 | |
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141 | G4double G4CoulombScatteringModel::SelectIsotope(const G4Element* elm) |
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142 | { |
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143 | G4double N = elm->GetN(); |
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144 | G4int ni = elm->GetNumberOfIsotopes(); |
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145 | if(ni > 0) { |
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146 | G4double* ab = elm->GetRelativeAbundanceVector(); |
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147 | G4double x = G4UniformRand(); |
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148 | G4int idx; |
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149 | for(idx=0; idx<ni; idx++) { |
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150 | x -= ab[idx]; |
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151 | if (x <= 0.0) break; |
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152 | } |
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153 | if(idx >= ni) { |
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154 | G4cout << "G4CoulombScatteringModel::SelectIsotope WARNING: " |
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155 | << "abandance vector for" |
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156 | << elm->GetName() << " is not normalised to unit" << G4endl; |
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157 | } else { |
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158 | N = G4double(elm->GetIsotope(idx)->GetN()); |
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159 | } |
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160 | } |
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161 | return N; |
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162 | } |
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163 | |
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164 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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165 | |
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166 | void G4CoulombScatteringModel::SampleSecondaries( |
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167 | std::vector<G4DynamicParticle*>* fvect, |
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168 | const G4MaterialCutsCouple* couple, |
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169 | const G4DynamicParticle* dp, |
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170 | G4double cutEnergy, |
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171 | G4double maxEnergy) |
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172 | { |
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173 | const G4Material* aMaterial = couple->GetMaterial(); |
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174 | const G4ParticleDefinition* p = dp->GetDefinition(); |
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175 | G4double kinEnergy = dp->GetKineticEnergy(); |
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176 | |
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177 | // Select isotope and setup |
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178 | SetupParticle(p); |
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179 | const G4Element* elm = |
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180 | SelectRandomAtom(aMaterial,p,kinEnergy,cutEnergy,maxEnergy); |
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181 | G4double Z = elm->GetZ(); |
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182 | G4double A = SelectIsotope(elm); |
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183 | G4int iz = G4int(Z); |
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184 | G4int ia = G4int(A + 0.5); |
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185 | |
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186 | G4double cross = |
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187 | ComputeCrossSectionPerAtom(p,kinEnergy,Z,A,cutEnergy,maxEnergy); |
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188 | |
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189 | G4double costm = cosTetMaxNuc; |
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190 | G4double formf = formfactA; |
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191 | if(G4UniformRand()*cross < elecXSection) { |
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192 | costm = cosTetMaxElec; |
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193 | formf = 0.0; |
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194 | } |
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195 | |
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196 | // G4cout << "SampleSec: Ekin= " << kinEnergy << " m1= " << m1 |
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197 | // << " Z= "<< Z << " A= " <<A<< G4endl; |
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198 | |
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199 | if(costm >= cosThetaMin) return; |
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200 | |
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201 | // kinematics in CM system |
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202 | G4double m1 = theParticleTable->GetIonTable()->GetNucleusMass(iz, ia); |
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203 | G4double etot = kinEnergy + mass; |
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204 | G4double ptot = sqrt(mom2); |
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205 | G4double bet = ptot/(etot + m1); |
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206 | G4double gam = 1.0/sqrt((1.0 - bet)*(1.0 + bet)); |
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207 | G4double pCM = gam*(ptot - bet*etot); |
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208 | G4double eCM = gam*(etot - bet*ptot); |
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209 | |
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210 | G4double x1 = 1. - cosThetaMin + screenZ; |
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211 | G4double x2 = 1. - costm; |
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212 | G4double x3 = cosThetaMin - costm; |
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213 | |
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214 | G4double grej, z, z1; |
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215 | do { |
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216 | z = G4UniformRand()*x3; |
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217 | z1 = (x1*x2 - screenZ*z)/(x1 + z); |
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218 | if(z1 < 0.0) z1 = 0.0; |
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219 | else if(z1 > 2.0) z1 = 2.0; |
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220 | grej = 1.0/(1.0 + formf*z1); |
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221 | } while ( G4UniformRand() > grej*grej ); |
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222 | |
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223 | G4double cost = 1.0 - z1; |
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224 | G4double sint= sqrt(z1*(2.0 - z1)); |
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225 | |
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226 | G4double phi = twopi * G4UniformRand(); |
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227 | |
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228 | // projectile after scattering |
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229 | G4double pzCM = pCM*cost; |
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230 | G4ThreeVector v1(pCM*cos(phi)*sint,pCM*sin(phi)*sint,gam*(pzCM + bet*eCM)); |
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231 | G4ThreeVector dir = dp->GetMomentumDirection(); |
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232 | G4ThreeVector newDirection = v1.unit(); |
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233 | newDirection.rotateUz(dir); |
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234 | fParticleChange->ProposeMomentumDirection(newDirection); |
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235 | G4double elab = gam*(eCM + bet*pzCM); |
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236 | G4double ekin = elab - mass; |
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237 | if(ekin < 0.0) ekin = 0.0; |
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238 | G4double plab = sqrt(ekin*(ekin + 2.0*mass)); |
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239 | fParticleChange->SetProposedKineticEnergy(ekin); |
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240 | |
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241 | // recoil |
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242 | G4double erec = kinEnergy - ekin; |
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243 | if(erec > Z*aMaterial->GetIonisation()->GetMeanExcitationEnergy()) { |
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244 | G4ParticleDefinition* ion = theParticleTable->FindIon(iz, ia, 0, iz); |
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245 | G4ThreeVector p2 = (ptot*dir - plab*newDirection).unit(); |
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246 | G4DynamicParticle* newdp = new G4DynamicParticle(ion, p2, erec); |
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247 | fvect->push_back(newdp); |
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248 | } else if(erec > 0.0) { |
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249 | fParticleChange->ProposeLocalEnergyDeposit(erec); |
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250 | fParticleChange->ProposeNonIonizingEnergyDeposit(erec); |
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251 | } |
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252 | } |
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253 | |
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254 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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255 | |
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256 | |
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