1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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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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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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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 | // $Id: G4GoudsmitSaundersonMscModel.cc,v 1.25 2010/06/25 09:41:40 gunter Exp $ |
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27 | // GEANT4 tag $Name: geant4-09-04-beta-01 $ |
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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 | // File name: G4GoudsmitSaundersonMscModel |
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34 | // |
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35 | // Author: Omrane Kadri |
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36 | // |
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37 | // Creation date: 20.02.2009 |
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38 | // |
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39 | // Modifications: |
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40 | // 04.03.2009 V.Ivanchenko cleanup and format according to Geant4 EM style |
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41 | // |
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42 | // 15.04.2009 O.Kadri: cleanup: discard no scattering and single scattering theta |
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43 | // sampling from SampleCosineTheta() which means the splitting |
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44 | // step into two sub-steps occur only for msc regime |
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45 | // |
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46 | // 12.06.2009 O.Kadri: linear log-log extrapolation of lambda0 & lambda1 between 1 GeV - 100 TeV |
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47 | // adding a theta min limit due to screening effect of the atomic nucleus |
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48 | // 26.08.2009 O.Kadri: Cubic Spline interpolation was replaced with polynomial method |
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49 | // within CalculateIntegrals method |
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50 | // 05.10.2009 O.Kadri: tuning small angle theta distributions |
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51 | // assuming the case of lambdan<1 as single scattering regime |
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52 | // tuning theta sampling for theta below the screening angle |
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53 | // 08.02.2010 O.Kadri: bugfix in compound xsection calculation and small angle computation |
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54 | // adding a rejection condition to hard collision angular sampling |
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55 | // ComputeTruePathLengthLimit was taken from G4WentzelVIModel |
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56 | // 26.03.2010 O.Kadri: direct xsection calculation not inverse of the inverse |
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57 | // angular sampling without large angle rejection method |
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58 | // longitudinal displacement is computed exactly from <z> |
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59 | // 12.05.2010 O.Kadri: exchange between target and projectile has as a condition the particle type (e-/e-) |
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60 | // some cleanup to minimize time consuming (adding lamdan12 & Qn12, changing the error to 1.0e-12 for scrA) |
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61 | // |
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62 | // |
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63 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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64 | //REFERENCES: |
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65 | //Ref.1:E. Benedito et al.,"Mixed simulation ... cross-sections", NIMB 174 (2001) pp 91-110; |
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66 | //Ref.2:I. Kawrakow et al.,"On the condensed ... transport",NIMB 142 (1998) pp 253-280; |
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67 | //Ref.3:I. Kawrakow et al.,"On the representation ... calculations",NIMB 134 (1998) pp 325-336; |
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68 | //Ref.4:Bielajew et al.,".....", NIMB 173 (2001) 332-343; |
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69 | //Ref.5:F. Salvat et al.,"ELSEPA--Dirac partial ...molecules", Comp.Phys.Comm.165 (2005) pp 157-190; |
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70 | //Ref.6:G4UrbanMscModel G4 9.2; |
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71 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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72 | #include "G4GoudsmitSaundersonMscModel.hh" |
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73 | #include "G4GoudsmitSaundersonTable.hh" |
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74 | |
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75 | #include "G4ParticleChangeForMSC.hh" |
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76 | #include "G4MaterialCutsCouple.hh" |
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77 | #include "G4DynamicParticle.hh" |
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78 | #include "G4Electron.hh" |
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79 | #include "G4Positron.hh" |
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80 | |
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81 | #include "G4LossTableManager.hh" |
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82 | #include "G4Track.hh" |
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83 | #include "G4PhysicsTable.hh" |
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84 | #include "Randomize.hh" |
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85 | |
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86 | using namespace std; |
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87 | |
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88 | G4double G4GoudsmitSaundersonMscModel::ener[] = {-1.}; |
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89 | G4double G4GoudsmitSaundersonMscModel::TCSE[103][106] ; |
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90 | G4double G4GoudsmitSaundersonMscModel::FTCSE[103][106] ; |
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91 | G4double G4GoudsmitSaundersonMscModel::TCSP[103][106] ; |
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92 | G4double G4GoudsmitSaundersonMscModel::FTCSP[103][106] ; |
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93 | |
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94 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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95 | G4GoudsmitSaundersonMscModel::G4GoudsmitSaundersonMscModel(const G4String& nam) |
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96 | : G4VMscModel(nam),lowKEnergy(0.1*keV),highKEnergy(100.*TeV),isInitialized(false) |
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97 | { |
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98 | fr=0.02,rangeinit=0.,masslimite=0.6*MeV, |
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99 | particle=0;tausmall=1.e-16;taulim=1.e-6;tlimit=1.e10*mm; |
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100 | tlimitmin=10.e-6*mm;geombig=1.e50*mm;geommin=1.e-3*mm,tgeom=geombig; |
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101 | tlimitminfix=1.e-6*mm;stepmin=tlimitminfix;lambdalimit=1.*mm;smallstep=1.e10; |
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102 | theManager=G4LossTableManager::Instance(); |
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103 | inside=false;insideskin=false; |
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104 | samplez=false; |
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105 | |
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106 | GSTable = new G4GoudsmitSaundersonTable(); |
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107 | |
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108 | if(ener[0] < 0.0){ |
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109 | G4cout << "### G4GoudsmitSaundersonMscModel loading ELSEPA data" << G4endl; |
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110 | LoadELSEPAXSections(); |
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111 | } |
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112 | } |
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113 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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114 | G4GoudsmitSaundersonMscModel::~G4GoudsmitSaundersonMscModel() |
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115 | { |
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116 | delete GSTable; |
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117 | } |
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118 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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119 | void G4GoudsmitSaundersonMscModel::Initialise(const G4ParticleDefinition* p, |
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120 | const G4DataVector&) |
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121 | { |
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122 | skindepth=skin*stepmin; |
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123 | SetParticle(p); |
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124 | if(isInitialized) return; |
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125 | fParticleChange = GetParticleChangeForMSC(); |
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126 | InitialiseSafetyHelper(); |
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127 | isInitialized=true; |
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128 | } |
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129 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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130 | |
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131 | G4double |
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132 | G4GoudsmitSaundersonMscModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition* p, |
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133 | G4double kineticEnergy,G4double Z, G4double, G4double, G4double) |
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134 | { |
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135 | G4double cs=0.0; |
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136 | G4double kinEnergy = kineticEnergy; |
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137 | if(kinEnergy<lowKEnergy) kinEnergy=lowKEnergy; |
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138 | if(kinEnergy>highKEnergy)kinEnergy=highKEnergy; |
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139 | |
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140 | G4double cs0; |
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141 | CalculateIntegrals(p,Z,kinEnergy,cs0,cs); |
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142 | |
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143 | return cs; |
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144 | } |
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145 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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146 | |
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147 | void |
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148 | G4GoudsmitSaundersonMscModel::SampleScattering(const G4DynamicParticle* dynParticle, |
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149 | G4double safety) |
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150 | { |
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151 | G4double kineticEnergy = dynParticle->GetKineticEnergy(); |
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152 | if((kineticEnergy <= 0.0) || (tPathLength <= tlimitminfix)|| |
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153 | (tPathLength/tausmall < lambda1)) return ; |
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154 | |
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155 | /////////////////////////////////////////// |
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156 | // Effective energy |
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157 | G4double eloss = theManager->GetEnergy(particle,tPathLength,currentCouple); |
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158 | if(eloss>0.5*kineticEnergy) |
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159 | {if((dynParticle->GetCharge())==-eplus)eloss=kineticEnergy-eloss;//exchange between target and projectile if they are electrons |
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160 | else eloss=0.5*kineticEnergy; |
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161 | } |
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162 | G4double ee = kineticEnergy - 0.5*eloss; |
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163 | G4double ttau = ee/electron_mass_c2; |
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164 | G4double ttau2 = ttau*ttau; |
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165 | G4double epsilonpp= eloss/ee; |
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166 | G4double cst1=epsilonpp*epsilonpp*(6+10*ttau+5*ttau2)/(24*ttau2+48*ttau+72); |
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167 | |
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168 | kineticEnergy *= (1 - cst1); |
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169 | /////////////////////////////////////////// |
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170 | // additivity rule for mixture and compound xsection's |
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171 | const G4Material* mat = currentCouple->GetMaterial(); |
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172 | const G4ElementVector* theElementVector = mat->GetElementVector(); |
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173 | const G4double* theAtomNumDensityVector = mat->GetVecNbOfAtomsPerVolume(); |
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174 | G4int nelm = mat->GetNumberOfElements(); |
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175 | G4double s0,s1; |
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176 | lambda0=0.; |
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177 | for(G4int i=0;i<nelm;i++) |
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178 | { |
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179 | CalculateIntegrals(particle,(*theElementVector)[i]->GetZ(),kineticEnergy,s0,s1); |
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180 | lambda0 += (theAtomNumDensityVector[i]*s0); |
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181 | } |
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182 | if(lambda0>DBL_MIN) lambda0 =1./lambda0; |
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183 | |
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184 | // Newton-Raphson root's finding method of scrA from: |
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185 | // Sig1(PWA)/Sig0(PWA)=g1=2*scrA*((1+scrA)*log(1+1/scrA)-1) |
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186 | G4double g1=0.0; |
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187 | if(lambda1>DBL_MIN) g1 = lambda0/lambda1; |
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188 | |
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189 | G4double logx0,x1,delta; |
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190 | G4double x0=g1/2.; |
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191 | do |
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192 | { |
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193 | logx0=std::log(1.+1./x0); |
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194 | x1 = x0-(x0*((1.+x0)*logx0-1.0)-g1/2.)/( (1.+2.*x0)*logx0-2.0); |
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195 | delta = std::abs( x1 - x0 ); |
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196 | x0 = x1; |
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197 | } while (delta > 1.0e-12); |
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198 | G4double scrA = x1; |
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199 | |
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200 | G4double lambdan=0.; |
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201 | |
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202 | if(lambda0>0.)lambdan=tPathLength/lambda0; |
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203 | if(lambdan<=1.0e-12)return; |
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204 | G4double lambdan12=0.5*lambdan; |
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205 | Qn1 = lambdan *g1;//2.* lambdan *scrA*((1.+scrA)*log(1.+1./scrA)-1.); |
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206 | Qn12 = 0.5*Qn1; |
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207 | |
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208 | G4double cosTheta1,sinTheta1,cosTheta2,sinTheta2; |
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209 | G4double cosPhi1=1.0,sinPhi1=0.0,cosPhi2=1.0,sinPhi2=0.0; |
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210 | G4double us=0.0,vs=0.0,ws=1.0,wss=0.,x_coord=0.0,y_coord=0.0,z_coord=1.0; |
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211 | |
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212 | G4double epsilon1=G4UniformRand(); |
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213 | G4double expn = std::exp(-lambdan); |
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214 | if(epsilon1<expn)// no scattering |
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215 | {return;} |
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216 | else if((epsilon1<((1.+lambdan)*expn))||(lambdan<1.))//single scattering (Rutherford DCS's) |
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217 | { |
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218 | |
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219 | G4double xi=G4UniformRand(); |
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220 | xi= 2.*scrA*xi/(1.-xi + scrA); |
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221 | if(xi<0.)xi=0.; |
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222 | else if(xi>2.)xi=2.; |
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223 | ws=1.-xi; |
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224 | wss=std::sqrt(xi*(2.-xi)); |
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225 | G4double phi0=CLHEP::twopi*G4UniformRand(); |
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226 | us=wss*cos(phi0); |
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227 | vs=wss*sin(phi0); |
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228 | } |
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229 | else // multiple scattering |
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230 | { |
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231 | // Ref.2 subsection 4.4 "The best solution found" |
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232 | // Sample first substep scattering angle |
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233 | SampleCosineTheta(lambdan12,scrA,cosTheta1,sinTheta1); |
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234 | G4double phi1 = CLHEP::twopi*G4UniformRand(); |
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235 | cosPhi1 = cos(phi1); |
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236 | sinPhi1 = sin(phi1); |
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237 | |
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238 | // Sample second substep scattering angle |
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239 | SampleCosineTheta(lambdan12,scrA,cosTheta2,sinTheta2); |
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240 | G4double phi2 = CLHEP::twopi*G4UniformRand(); |
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241 | cosPhi2 = cos(phi2); |
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242 | sinPhi2 = sin(phi2); |
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243 | |
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244 | // Overall scattering direction |
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245 | us = sinTheta2*(cosTheta1*cosPhi1*cosPhi2 - sinPhi1*sinPhi2) + cosTheta2*sinTheta1*cosPhi1; |
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246 | vs = sinTheta2*(cosTheta1*sinPhi1*cosPhi2 + cosPhi1*sinPhi2) + cosTheta2*sinTheta1*sinPhi1; |
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247 | ws = cosTheta1*cosTheta2 - sinTheta1*sinTheta2*cosPhi2; |
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248 | G4double sqrtA=sqrt(scrA); |
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249 | if(acos(ws)<sqrtA)//small angle approximation for theta less than screening angle |
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250 | { |
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251 | G4int i=0; |
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252 | do{i++; |
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253 | ws=1.+Qn12*log(G4UniformRand()); |
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254 | }while((fabs(ws)>1.)&&(i<20));//i<20 to avoid time consuming during the run |
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255 | if(i>=19)ws=cos(sqrtA); |
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256 | |
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257 | wss=std::sqrt((1.-ws)*(1.0+ws)); |
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258 | us=wss*cos(phi1); |
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259 | vs=wss*sin(phi1); |
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260 | } |
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261 | } |
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262 | |
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263 | G4ThreeVector oldDirection = dynParticle->GetMomentumDirection(); |
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264 | G4ThreeVector newDirection(us,vs,ws); |
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265 | newDirection.rotateUz(oldDirection); |
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266 | fParticleChange->ProposeMomentumDirection(newDirection); |
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267 | |
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268 | if((safety > tlimitminfix)&&latDisplasment) |
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269 | { |
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270 | if(Qn1<0.02)// corresponding to error less than 1% in the exact formula of <z> |
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271 | z_coord = 1.0 - Qn1*(0.5 - Qn1/6.); |
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272 | else z_coord = (1.-std::exp(-Qn1))/Qn1; |
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273 | |
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274 | G4double rr=std::sqrt((1.- z_coord*z_coord)/(1.-ws*ws)); |
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275 | x_coord = rr*us; |
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276 | y_coord = rr*vs; |
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277 | // displacement is computed relatively to the end point |
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278 | z_coord -= 1.0; |
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279 | rr = std::sqrt(x_coord*x_coord+y_coord*y_coord+z_coord*z_coord); |
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280 | G4double r = rr*zPathLength; |
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281 | /* |
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282 | G4cout << "G4GS::SampleSecondaries: e(MeV)= " << kineticEnergy |
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283 | << " sinTheta= " << sqrt(1.0 - ws*ws) << " r(mm)= " << r |
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284 | << " trueStep(mm)= " << tPathLength |
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285 | << " geomStep(mm)= " << zPathLength |
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286 | << G4endl; |
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287 | */ |
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288 | if(tPathLength<=zPathLength)return; |
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289 | if(r > tlimitminfix) { |
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290 | |
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291 | G4ThreeVector Direction(x_coord/rr,y_coord/rr,z_coord/rr); |
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292 | Direction.rotateUz(oldDirection); |
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293 | |
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294 | ComputeDisplacement(fParticleChange, Direction, r, safety); |
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295 | } |
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296 | } |
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297 | } |
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298 | |
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299 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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300 | |
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301 | void |
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302 | G4GoudsmitSaundersonMscModel::SampleCosineTheta(G4double lambdan, G4double scrA, |
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303 | G4double &cost, G4double &sint) |
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304 | { |
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305 | G4double xi=0.; |
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306 | |
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307 | if (Qn12<0.001) |
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308 | {G4double r1,tet; |
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309 | do{ |
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310 | r1=G4UniformRand(); |
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311 | xi=-Qn12*log(G4UniformRand()); |
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312 | tet=acos(1.-xi); |
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313 | }while(tet*r1*r1>sin(tet)); |
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314 | } |
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315 | else if(Qn12>0.5)xi=2.*G4UniformRand(); |
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316 | else xi=2.*(GSTable->SampleTheta(lambdan,scrA,G4UniformRand())); |
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317 | |
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318 | |
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319 | if(xi<0.)xi=0.; |
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320 | else if(xi>2.)xi=2.; |
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321 | |
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322 | cost=(1. - xi); |
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323 | sint=sqrt(xi*(2.-xi)); |
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324 | |
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325 | } |
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326 | |
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327 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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328 | // Polynomial log-log interpolation of Lambda0 and Lambda1 between 100 eV - 1 GeV |
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329 | // linear log-log extrapolation between 1 GeV - 100 TeV |
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330 | |
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331 | void |
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332 | G4GoudsmitSaundersonMscModel::CalculateIntegrals(const G4ParticleDefinition* p,G4double Z, |
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333 | G4double kinEnergy,G4double &Sig0, |
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334 | G4double &Sig1) |
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335 | { |
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336 | G4double x1,x2,y1,y2,acoeff,bcoeff; |
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337 | G4double kineticE = kinEnergy; |
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338 | if(kineticE<lowKEnergy)kineticE=lowKEnergy; |
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339 | if(kineticE>highKEnergy)kineticE=highKEnergy; |
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340 | kineticE /= eV; |
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341 | G4double logE=std::log(kineticE); |
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342 | |
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343 | G4int iZ = G4int(Z); |
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344 | if(iZ > 103) iZ = 103; |
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345 | |
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346 | G4int enerInd=0; |
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347 | for(G4int i=0;i<105;i++) |
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348 | { |
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349 | if((logE>=ener[i])&&(logE<ener[i+1])){enerInd=i;break;} |
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350 | } |
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351 | |
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352 | if(p==G4Electron::Electron()) |
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353 | { |
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354 | if(kineticE<=1.0e+9)//Interpolation of the form y=ax²+b |
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355 | { |
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356 | x1=ener[enerInd]; |
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357 | x2=ener[enerInd+1]; |
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358 | y1=TCSE[iZ-1][enerInd]; |
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359 | y2=TCSE[iZ-1][enerInd+1]; |
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360 | acoeff=(y2-y1)/(x2*x2-x1*x1); |
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361 | bcoeff=y2-acoeff*x2*x2; |
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362 | Sig0=acoeff*logE*logE+bcoeff; |
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363 | Sig0 =std::exp(Sig0); |
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364 | y1=FTCSE[iZ-1][enerInd]; |
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365 | y2=FTCSE[iZ-1][enerInd+1]; |
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366 | acoeff=(y2-y1)/(x2*x2-x1*x1); |
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367 | bcoeff=y2-acoeff*x2*x2; |
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368 | Sig1=acoeff*logE*logE+bcoeff; |
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369 | Sig1=std::exp(Sig1); |
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370 | } |
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371 | else //Interpolation of the form y=ax+b |
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372 | { |
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373 | x1=ener[104]; |
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374 | x2=ener[105]; |
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375 | y1=TCSE[iZ-1][104]; |
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376 | y2=TCSE[iZ-1][105]; |
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377 | Sig0=(y2-y1)*(logE-x1)/(x2-x1)+y1; |
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378 | Sig0=std::exp(Sig0); |
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379 | y1=FTCSE[iZ-1][104]; |
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380 | y2=FTCSE[iZ-1][105]; |
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381 | Sig1=(y2-y1)*(logE-x1)/(x2-x1)+y1; |
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382 | Sig1=std::exp(Sig1); |
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383 | } |
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384 | } |
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385 | if(p==G4Positron::Positron()) |
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386 | { |
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387 | if(kinEnergy<=1.0e+9) |
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388 | { |
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389 | x1=ener[enerInd]; |
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390 | x2=ener[enerInd+1]; |
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391 | y1=TCSP[iZ-1][enerInd]; |
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392 | y2=TCSP[iZ-1][enerInd+1]; |
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393 | acoeff=(y2-y1)/(x2*x2-x1*x1); |
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394 | bcoeff=y2-acoeff*x2*x2; |
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395 | Sig0=acoeff*logE*logE+bcoeff; |
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396 | Sig0 =std::exp(Sig0); |
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397 | y1=FTCSP[iZ-1][enerInd]; |
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398 | y2=FTCSP[iZ-1][enerInd+1]; |
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399 | acoeff=(y2-y1)/(x2*x2-x1*x1); |
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400 | bcoeff=y2-acoeff*x2*x2; |
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401 | Sig1=acoeff*logE*logE+bcoeff; |
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402 | Sig1=std::exp(Sig1); |
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403 | } |
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404 | else |
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405 | { |
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406 | x1=ener[104]; |
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407 | x2=ener[105]; |
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408 | y1=TCSP[iZ-1][104]; |
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409 | y2=TCSP[iZ-1][105]; |
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410 | Sig0=(y2-y1)*(logE-x1)/(x2-x1)+y1; |
---|
411 | Sig0 =std::exp(Sig0); |
---|
412 | y1=FTCSP[iZ-1][104]; |
---|
413 | y2=FTCSP[iZ-1][105]; |
---|
414 | Sig1=(y2-y1)*(logE-x1)/(x2-x1)+y1; |
---|
415 | Sig1=std::exp(Sig1); |
---|
416 | } |
---|
417 | } |
---|
418 | |
---|
419 | Sig0 *= barn; |
---|
420 | Sig1 *= barn; |
---|
421 | |
---|
422 | } |
---|
423 | |
---|
424 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
425 | //t->g->t step transformations taken from Ref.6 |
---|
426 | |
---|
427 | G4double |
---|
428 | G4GoudsmitSaundersonMscModel::ComputeTruePathLengthLimit(const G4Track& track, |
---|
429 | G4PhysicsTable* theTable, |
---|
430 | G4double currentMinimalStep) |
---|
431 | { |
---|
432 | tPathLength = currentMinimalStep; |
---|
433 | G4StepPoint* sp = track.GetStep()->GetPreStepPoint(); |
---|
434 | G4StepStatus stepStatus = sp->GetStepStatus(); |
---|
435 | |
---|
436 | const G4DynamicParticle* dp = track.GetDynamicParticle(); |
---|
437 | |
---|
438 | if(stepStatus == fUndefined) { |
---|
439 | inside = false; |
---|
440 | insideskin = false; |
---|
441 | tlimit = geombig; |
---|
442 | SetParticle( dp->GetDefinition() ); |
---|
443 | } |
---|
444 | |
---|
445 | theLambdaTable = theTable; |
---|
446 | currentCouple = track.GetMaterialCutsCouple(); |
---|
447 | currentMaterialIndex = currentCouple->GetIndex(); |
---|
448 | currentKinEnergy = dp->GetKineticEnergy(); |
---|
449 | currentRange = |
---|
450 | theManager->GetRangeFromRestricteDEDX(particle,currentKinEnergy,currentCouple); |
---|
451 | |
---|
452 | lambda1 = GetLambda(currentKinEnergy); |
---|
453 | |
---|
454 | // stop here if small range particle |
---|
455 | if(inside) return tPathLength; |
---|
456 | |
---|
457 | if(tPathLength > currentRange) tPathLength = currentRange; |
---|
458 | |
---|
459 | G4double presafety = sp->GetSafety(); |
---|
460 | |
---|
461 | //G4cout << "G4GS::StepLimit tPathLength= " |
---|
462 | // <<tPathLength<<" safety= " << presafety |
---|
463 | // << " range= " <<currentRange<< " lambda= "<<lambda1 |
---|
464 | // << " Alg: " << steppingAlgorithm <<G4endl; |
---|
465 | |
---|
466 | // far from geometry boundary |
---|
467 | if(currentRange < presafety) |
---|
468 | { |
---|
469 | inside = true; |
---|
470 | return tPathLength; |
---|
471 | } |
---|
472 | |
---|
473 | // standard version |
---|
474 | // |
---|
475 | if (steppingAlgorithm == fUseDistanceToBoundary) |
---|
476 | { |
---|
477 | //compute geomlimit and presafety |
---|
478 | G4double geomlimit = ComputeGeomLimit(track, presafety, tPathLength); |
---|
479 | |
---|
480 | // is far from boundary |
---|
481 | if(currentRange <= presafety) |
---|
482 | { |
---|
483 | inside = true; |
---|
484 | return tPathLength; |
---|
485 | } |
---|
486 | |
---|
487 | smallstep += 1.; |
---|
488 | insideskin = false; |
---|
489 | |
---|
490 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
491 | { |
---|
492 | rangeinit = currentRange; |
---|
493 | if(stepStatus == fUndefined) smallstep = 1.e10; |
---|
494 | else smallstep = 1.; |
---|
495 | |
---|
496 | //define stepmin here (it depends on lambda!) |
---|
497 | //rough estimation of lambda_elastic/lambda_transport |
---|
498 | G4double rat = currentKinEnergy/MeV ; |
---|
499 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
500 | //stepmin ~ lambda_elastic |
---|
501 | stepmin = rat*lambda1; |
---|
502 | skindepth = skin*stepmin; |
---|
503 | //define tlimitmin |
---|
504 | tlimitmin = 10.*stepmin; |
---|
505 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
506 | |
---|
507 | //G4cout << "rangeinit= " << rangeinit << " stepmin= " << stepmin |
---|
508 | // << " tlimitmin= " << tlimitmin << " geomlimit= " << geomlimit <<G4endl; |
---|
509 | // constraint from the geometry |
---|
510 | if((geomlimit < geombig) && (geomlimit > geommin)) |
---|
511 | { |
---|
512 | if(stepStatus == fGeomBoundary) |
---|
513 | tgeom = geomlimit/facgeom; |
---|
514 | else |
---|
515 | tgeom = 2.*geomlimit/facgeom; |
---|
516 | } |
---|
517 | else |
---|
518 | tgeom = geombig; |
---|
519 | |
---|
520 | } |
---|
521 | |
---|
522 | //step limit |
---|
523 | tlimit = facrange*rangeinit; |
---|
524 | if(tlimit < facsafety*presafety) |
---|
525 | tlimit = facsafety*presafety; |
---|
526 | |
---|
527 | //lower limit for tlimit |
---|
528 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
529 | |
---|
530 | if(tlimit > tgeom) tlimit = tgeom; |
---|
531 | |
---|
532 | //G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit |
---|
533 | // << " tlimit= " << tlimit << " presafety= " << presafety << G4endl; |
---|
534 | |
---|
535 | // shortcut |
---|
536 | if((tPathLength < tlimit) && (tPathLength < presafety) && |
---|
537 | (smallstep >= skin) && (tPathLength < geomlimit-0.999*skindepth)) |
---|
538 | return tPathLength; |
---|
539 | |
---|
540 | // step reduction near to boundary |
---|
541 | if(smallstep < skin) |
---|
542 | { |
---|
543 | tlimit = stepmin; |
---|
544 | insideskin = true; |
---|
545 | } |
---|
546 | else if(geomlimit < geombig) |
---|
547 | { |
---|
548 | if(geomlimit > skindepth) |
---|
549 | { |
---|
550 | if(tlimit > geomlimit-0.999*skindepth) |
---|
551 | tlimit = geomlimit-0.999*skindepth; |
---|
552 | } |
---|
553 | else |
---|
554 | { |
---|
555 | insideskin = true; |
---|
556 | if(tlimit > stepmin) tlimit = stepmin; |
---|
557 | } |
---|
558 | } |
---|
559 | |
---|
560 | if(tlimit < stepmin) tlimit = stepmin; |
---|
561 | |
---|
562 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
563 | |
---|
564 | } |
---|
565 | // for 'normal' simulation with or without magnetic field |
---|
566 | // there no small step/single scattering at boundaries |
---|
567 | else if(steppingAlgorithm == fUseSafety) |
---|
568 | { |
---|
569 | // compute presafety again if presafety <= 0 and no boundary |
---|
570 | // i.e. when it is needed for optimization purposes |
---|
571 | if((stepStatus != fGeomBoundary) && (presafety < tlimitminfix)) |
---|
572 | presafety = ComputeSafety(sp->GetPosition(),tPathLength); |
---|
573 | |
---|
574 | // is far from boundary |
---|
575 | if(currentRange < presafety) |
---|
576 | { |
---|
577 | inside = true; |
---|
578 | return tPathLength; |
---|
579 | } |
---|
580 | |
---|
581 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
582 | { |
---|
583 | rangeinit = currentRange; |
---|
584 | fr = facrange; |
---|
585 | // 9.1 like stepping for e+/e- only (not for muons,hadrons) |
---|
586 | if(mass < masslimite) |
---|
587 | { |
---|
588 | if(lambda1 > currentRange) |
---|
589 | rangeinit = lambda1; |
---|
590 | if(lambda1 > lambdalimit) |
---|
591 | fr *= 0.75+0.25*lambda1/lambdalimit; |
---|
592 | } |
---|
593 | |
---|
594 | //lower limit for tlimit |
---|
595 | G4double rat = currentKinEnergy/MeV ; |
---|
596 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
597 | tlimitmin = 10.*lambda1*rat; |
---|
598 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
599 | } |
---|
600 | //step limit |
---|
601 | tlimit = fr*rangeinit; |
---|
602 | |
---|
603 | if(tlimit < facsafety*presafety) |
---|
604 | tlimit = facsafety*presafety; |
---|
605 | |
---|
606 | //lower limit for tlimit |
---|
607 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
608 | |
---|
609 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
610 | } |
---|
611 | |
---|
612 | // version similar to 7.1 (needed for some experiments) |
---|
613 | else |
---|
614 | { |
---|
615 | if (stepStatus == fGeomBoundary) |
---|
616 | { |
---|
617 | if (currentRange > lambda1) tlimit = facrange*currentRange; |
---|
618 | else tlimit = facrange*lambda1; |
---|
619 | |
---|
620 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
621 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
622 | } |
---|
623 | } |
---|
624 | //G4cout << "tPathLength= " << tPathLength |
---|
625 | // << " currentMinimalStep= " << currentMinimalStep << G4endl; |
---|
626 | return tPathLength ; |
---|
627 | } |
---|
628 | |
---|
629 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
630 | // taken from Ref.6 |
---|
631 | G4double G4GoudsmitSaundersonMscModel::ComputeGeomPathLength(G4double) |
---|
632 | { |
---|
633 | par1 = -1. ; |
---|
634 | par2 = par3 = 0. ; |
---|
635 | |
---|
636 | // do the true -> geom transformation |
---|
637 | zPathLength = tPathLength; |
---|
638 | |
---|
639 | // z = t for very small tPathLength |
---|
640 | if(tPathLength < tlimitminfix) return zPathLength; |
---|
641 | |
---|
642 | // this correction needed to run MSC with eIoni and eBrem inactivated |
---|
643 | // and makes no harm for a normal run |
---|
644 | if(tPathLength > currentRange) |
---|
645 | tPathLength = currentRange ; |
---|
646 | |
---|
647 | G4double tau = tPathLength/lambda1 ; |
---|
648 | |
---|
649 | if ((tau <= tausmall) || insideskin) { |
---|
650 | zPathLength = tPathLength; |
---|
651 | if(zPathLength > lambda1) zPathLength = lambda1; |
---|
652 | return zPathLength; |
---|
653 | } |
---|
654 | |
---|
655 | G4double zmean = tPathLength; |
---|
656 | if (tPathLength < currentRange*dtrl) { |
---|
657 | if(tau < taulim) zmean = tPathLength*(1.-0.5*tau) ; |
---|
658 | else zmean = lambda1*(1.-exp(-tau)); |
---|
659 | } else if(currentKinEnergy < mass) { |
---|
660 | par1 = 1./currentRange ; |
---|
661 | par2 = 1./(par1*lambda1) ; |
---|
662 | par3 = 1.+par2 ; |
---|
663 | if(tPathLength < currentRange) |
---|
664 | zmean = (1.-exp(par3*log(1.-tPathLength/currentRange)))/(par1*par3) ; |
---|
665 | else |
---|
666 | zmean = 1./(par1*par3) ; |
---|
667 | } else { |
---|
668 | G4double T1 = theManager->GetEnergy(particle,currentRange-tPathLength, |
---|
669 | currentCouple); |
---|
670 | |
---|
671 | lambda11 = GetLambda(T1); |
---|
672 | |
---|
673 | par1 = (lambda1-lambda11)/(lambda1*tPathLength) ; |
---|
674 | par2 = 1./(par1*lambda1) ; |
---|
675 | par3 = 1.+par2 ; |
---|
676 | zmean = (1.-exp(par3*log(lambda11/lambda1)))/(par1*par3) ; |
---|
677 | } |
---|
678 | |
---|
679 | zPathLength = zmean ; |
---|
680 | // sample z |
---|
681 | if(samplez) { |
---|
682 | |
---|
683 | const G4double ztmax = 0.99; |
---|
684 | G4double zt = zmean/tPathLength ; |
---|
685 | |
---|
686 | if (tPathLength > stepmin && zt < ztmax) { |
---|
687 | |
---|
688 | G4double u,cz1; |
---|
689 | if(zt >= 0.333333333) { |
---|
690 | |
---|
691 | G4double cz = 0.5*(3.*zt-1.)/(1.-zt) ; |
---|
692 | cz1 = 1.+cz ; |
---|
693 | G4double u0 = cz/cz1 ; |
---|
694 | G4double grej ; |
---|
695 | do { |
---|
696 | u = exp(log(G4UniformRand())/cz1) ; |
---|
697 | grej = exp(cz*log(u/u0))*(1.-u)/(1.-u0) ; |
---|
698 | } while (grej < G4UniformRand()) ; |
---|
699 | |
---|
700 | } else { |
---|
701 | cz1 = 1./zt-1.; |
---|
702 | u = 1.-exp(log(G4UniformRand())/cz1) ; |
---|
703 | } |
---|
704 | zPathLength = tPathLength*u ; |
---|
705 | } |
---|
706 | } |
---|
707 | if(zPathLength > lambda1) zPathLength = lambda1; |
---|
708 | //G4cout << "zPathLength= " << zPathLength << " lambda1= " << lambda1 << G4endl; |
---|
709 | |
---|
710 | return zPathLength; |
---|
711 | } |
---|
712 | |
---|
713 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
714 | // taken from Ref.6 |
---|
715 | G4double |
---|
716 | G4GoudsmitSaundersonMscModel::ComputeTrueStepLength(G4double geomStepLength) |
---|
717 | { |
---|
718 | // step defined other than transportation |
---|
719 | if(geomStepLength == zPathLength && tPathLength <= currentRange) |
---|
720 | return tPathLength; |
---|
721 | |
---|
722 | // t = z for very small step |
---|
723 | zPathLength = geomStepLength; |
---|
724 | tPathLength = geomStepLength; |
---|
725 | if(geomStepLength < tlimitminfix) return tPathLength; |
---|
726 | |
---|
727 | // recalculation |
---|
728 | if((geomStepLength > lambda1*tausmall) && !insideskin) |
---|
729 | { |
---|
730 | if(par1 < 0.) |
---|
731 | tPathLength = -lambda1*log(1.-geomStepLength/lambda1) ; |
---|
732 | else |
---|
733 | { |
---|
734 | if(par1*par3*geomStepLength < 1.) |
---|
735 | tPathLength = (1.-exp(log(1.-par1*par3*geomStepLength)/par3))/par1 ; |
---|
736 | else |
---|
737 | tPathLength = currentRange; |
---|
738 | } |
---|
739 | } |
---|
740 | if(tPathLength < geomStepLength) tPathLength = geomStepLength; |
---|
741 | //G4cout << "tPathLength= " << tPathLength << " step= " << geomStepLength << G4endl; |
---|
742 | |
---|
743 | return tPathLength; |
---|
744 | } |
---|
745 | |
---|
746 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
747 | //Total & first transport x sections for e-/e+ generated from ELSEPA code |
---|
748 | |
---|
749 | void G4GoudsmitSaundersonMscModel::LoadELSEPAXSections() |
---|
750 | { |
---|
751 | G4String filename = "XSECTIONS.dat"; |
---|
752 | |
---|
753 | char* path = getenv("G4LEDATA"); |
---|
754 | if (!path) |
---|
755 | { |
---|
756 | G4String excep = "G4GoudsmitSaundersonTable: G4LEDATA environment variable not set properly"; |
---|
757 | G4Exception(excep); |
---|
758 | } |
---|
759 | |
---|
760 | G4String pathString(path); |
---|
761 | G4String dirFile = pathString + "/msc_GS/" + filename; |
---|
762 | FILE *infile; |
---|
763 | infile = fopen(dirFile,"r"); |
---|
764 | if (infile == 0) |
---|
765 | { |
---|
766 | G4String excep = "G4GoudsmitSaunderson - data files: " + dirFile + " not found"; |
---|
767 | G4Exception(excep); |
---|
768 | } |
---|
769 | |
---|
770 | // Read parameters from tables and take logarithms |
---|
771 | G4float aRead; |
---|
772 | for(G4int i=0 ; i<106 ;i++){ |
---|
773 | fscanf(infile,"%f\t",&aRead); |
---|
774 | if(aRead > 0.0) aRead = log(aRead); |
---|
775 | else aRead = 0.0; |
---|
776 | ener[i]=aRead; |
---|
777 | } |
---|
778 | for(G4int j=0;j<103;j++){ |
---|
779 | for(G4int i=0;i<106;i++){ |
---|
780 | fscanf(infile,"%f\t",&aRead); |
---|
781 | if(aRead > 0.0) aRead = log(aRead); |
---|
782 | else aRead = 0.0; |
---|
783 | TCSE[j][i]=aRead; |
---|
784 | } |
---|
785 | } |
---|
786 | for(G4int j=0;j<103;j++){ |
---|
787 | for(G4int i=0;i<106;i++){ |
---|
788 | fscanf(infile,"%f\t",&aRead); |
---|
789 | if(aRead > 0.0) aRead = log(aRead); |
---|
790 | else aRead = 0.0; |
---|
791 | FTCSE[j][i]=aRead; |
---|
792 | } |
---|
793 | } |
---|
794 | for(G4int j=0;j<103;j++){ |
---|
795 | for(G4int i=0;i<106;i++){ |
---|
796 | fscanf(infile,"%f\t",&aRead); |
---|
797 | if(aRead > 0.0) aRead = log(aRead); |
---|
798 | else aRead = 0.0; |
---|
799 | TCSP[j][i]=aRead; |
---|
800 | } |
---|
801 | } |
---|
802 | for(G4int j=0;j<103;j++){ |
---|
803 | for(G4int i=0;i<106;i++){ |
---|
804 | fscanf(infile,"%f\t",&aRead); |
---|
805 | if(aRead > 0.0) aRead = log(aRead); |
---|
806 | else aRead = 0.0; |
---|
807 | FTCSP[j][i]=aRead; |
---|
808 | } |
---|
809 | } |
---|
810 | |
---|
811 | fclose(infile); |
---|
812 | |
---|
813 | } |
---|
814 | |
---|
815 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|