1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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7 | // * conditions of the Geant4 Software License, included in the file * |
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8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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9 | // * include a list of copyright holders. * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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12 | // * institutes,nor the agencies providing financial support for this * |
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13 | // * work make any representation or warranty, express or implied, * |
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14 | // * regarding this software system or assume any liability for its * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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16 | // * for the full disclaimer and the limitation of liability. * |
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17 | // * * |
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18 | // * This code implementation is the result of the scientific and * |
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19 | // * technical work of the GEANT4 collaboration. * |
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20 | // * By using, copying, modifying or distributing the software (or * |
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21 | // * any work based on the software) you agree to acknowledge its * |
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22 | // * use in resulting scientific publications, and indicate your * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // $Id: G4OpRayleigh.cc,v 1.17 2008/10/24 19:51:12 gum Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-02 $ |
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29 | // |
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30 | // |
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31 | //////////////////////////////////////////////////////////////////////// |
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32 | // Optical Photon Rayleigh Scattering Class Implementation |
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33 | //////////////////////////////////////////////////////////////////////// |
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34 | // |
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35 | // File: G4OpRayleigh.cc |
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36 | // Description: Discrete Process -- Rayleigh scattering of optical |
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37 | // photons |
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38 | // Version: 1.0 |
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39 | // Created: 1996-05-31 |
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40 | // Author: Juliet Armstrong |
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41 | // Updated: 2005-07-28 - add G4ProcessType to constructor |
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42 | // 2001-10-18 by Peter Gumplinger |
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43 | // eliminate unused variable warning on Linux (gcc-2.95.2) |
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44 | // 2001-09-18 by mma |
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45 | // >numOfMaterials=G4Material::GetNumberOfMaterials() in BuildPhy |
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46 | // 2001-01-30 by Peter Gumplinger |
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47 | // > allow for positiv and negative CosTheta and force the |
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48 | // > new momentum direction to be in the same plane as the |
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49 | // > new and old polarization vectors |
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50 | // 2001-01-29 by Peter Gumplinger |
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51 | // > fix calculation of SinTheta (from CosTheta) |
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52 | // 1997-04-09 by Peter Gumplinger |
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53 | // > new physics/tracking scheme |
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54 | // mail: gum@triumf.ca |
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55 | // |
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56 | //////////////////////////////////////////////////////////////////////// |
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57 | |
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58 | #include "G4ios.hh" |
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59 | #include "G4OpProcessSubType.hh" |
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60 | |
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61 | #include "G4OpRayleigh.hh" |
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62 | |
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63 | ///////////////////////// |
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64 | // Class Implementation |
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65 | ///////////////////////// |
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66 | |
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67 | ////////////// |
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68 | // Operators |
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69 | ////////////// |
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70 | |
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71 | // G4OpRayleigh::operator=(const G4OpRayleigh &right) |
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72 | // { |
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73 | // } |
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74 | |
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75 | ///////////////// |
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76 | // Constructors |
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77 | ///////////////// |
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78 | |
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79 | G4OpRayleigh::G4OpRayleigh(const G4String& processName, G4ProcessType type) |
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80 | : G4VDiscreteProcess(processName, type) |
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81 | { |
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82 | SetProcessSubType(fOpRayleigh); |
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83 | |
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84 | thePhysicsTable = 0; |
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85 | |
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86 | DefaultWater = false; |
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87 | |
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88 | if (verboseLevel>0) { |
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89 | G4cout << GetProcessName() << " is created " << G4endl; |
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90 | } |
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91 | |
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92 | BuildThePhysicsTable(); |
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93 | } |
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94 | |
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95 | // G4OpRayleigh::G4OpRayleigh(const G4OpRayleigh &right) |
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96 | // { |
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97 | // } |
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98 | |
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99 | //////////////// |
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100 | // Destructors |
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101 | //////////////// |
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102 | |
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103 | G4OpRayleigh::~G4OpRayleigh() |
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104 | { |
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105 | if (thePhysicsTable!= 0) { |
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106 | thePhysicsTable->clearAndDestroy(); |
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107 | delete thePhysicsTable; |
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108 | } |
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109 | } |
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110 | |
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111 | //////////// |
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112 | // Methods |
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113 | //////////// |
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114 | |
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115 | // PostStepDoIt |
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116 | // ------------- |
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117 | // |
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118 | G4VParticleChange* |
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119 | G4OpRayleigh::PostStepDoIt(const G4Track& aTrack, const G4Step& aStep) |
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120 | { |
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121 | aParticleChange.Initialize(aTrack); |
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122 | |
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123 | const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle(); |
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124 | |
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125 | if (verboseLevel>0) { |
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126 | G4cout << "Scattering Photon!" << G4endl; |
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127 | G4cout << "Old Momentum Direction: " |
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128 | << aParticle->GetMomentumDirection() << G4endl; |
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129 | G4cout << "Old Polarization: " |
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130 | << aParticle->GetPolarization() << G4endl; |
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131 | } |
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132 | |
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133 | // find polar angle w.r.t. old polarization vector |
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134 | |
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135 | G4double rand = G4UniformRand(); |
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136 | |
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137 | G4double CosTheta = std::pow(rand, 1./3.); |
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138 | G4double SinTheta = std::sqrt(1.-CosTheta*CosTheta); |
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139 | |
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140 | if(G4UniformRand() < 0.5)CosTheta = -CosTheta; |
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141 | |
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142 | // find azimuthal angle w.r.t old polarization vector |
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143 | |
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144 | rand = G4UniformRand(); |
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145 | |
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146 | G4double Phi = twopi*rand; |
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147 | G4double SinPhi = std::sin(Phi); |
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148 | G4double CosPhi = std::cos(Phi); |
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149 | |
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150 | G4double unit_x = SinTheta * CosPhi; |
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151 | G4double unit_y = SinTheta * SinPhi; |
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152 | G4double unit_z = CosTheta; |
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153 | |
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154 | G4ThreeVector NewPolarization (unit_x,unit_y,unit_z); |
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155 | |
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156 | // Rotate new polarization direction into global reference system |
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157 | |
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158 | G4ThreeVector OldPolarization = aParticle->GetPolarization(); |
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159 | OldPolarization = OldPolarization.unit(); |
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160 | |
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161 | NewPolarization.rotateUz(OldPolarization); |
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162 | NewPolarization = NewPolarization.unit(); |
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163 | |
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164 | // -- new momentum direction is normal to the new |
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165 | // polarization vector and in the same plane as the |
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166 | // old and new polarization vectors -- |
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167 | |
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168 | G4ThreeVector NewMomentumDirection = |
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169 | OldPolarization - NewPolarization * CosTheta; |
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170 | |
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171 | if(G4UniformRand() < 0.5)NewMomentumDirection = -NewMomentumDirection; |
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172 | NewMomentumDirection = NewMomentumDirection.unit(); |
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173 | |
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174 | aParticleChange.ProposePolarization(NewPolarization); |
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175 | |
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176 | aParticleChange.ProposeMomentumDirection(NewMomentumDirection); |
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177 | |
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178 | if (verboseLevel>0) { |
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179 | G4cout << "New Polarization: " |
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180 | << NewPolarization << G4endl; |
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181 | G4cout << "Polarization Change: " |
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182 | << *(aParticleChange.GetPolarization()) << G4endl; |
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183 | G4cout << "New Momentum Direction: " |
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184 | << NewMomentumDirection << G4endl; |
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185 | G4cout << "Momentum Change: " |
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186 | << *(aParticleChange.GetMomentumDirection()) << G4endl; |
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187 | } |
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188 | |
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189 | return G4VDiscreteProcess::PostStepDoIt(aTrack, aStep); |
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190 | } |
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191 | |
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192 | // BuildThePhysicsTable for the Rayleigh Scattering process |
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193 | // -------------------------------------------------------- |
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194 | // |
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195 | void G4OpRayleigh::BuildThePhysicsTable() |
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196 | { |
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197 | // Builds a table of scattering lengths for each material |
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198 | |
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199 | if (thePhysicsTable) return; |
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200 | |
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201 | const G4MaterialTable* theMaterialTable= |
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202 | G4Material::GetMaterialTable(); |
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203 | G4int numOfMaterials = G4Material::GetNumberOfMaterials(); |
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204 | |
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205 | // create a new physics table |
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206 | |
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207 | thePhysicsTable = new G4PhysicsTable(numOfMaterials); |
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208 | |
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209 | // loop for materials |
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210 | |
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211 | for (G4int i=0 ; i < numOfMaterials; i++) |
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212 | { |
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213 | G4PhysicsOrderedFreeVector* ScatteringLengths = |
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214 | new G4PhysicsOrderedFreeVector(); |
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215 | |
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216 | G4MaterialPropertiesTable *aMaterialPropertiesTable = |
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217 | (*theMaterialTable)[i]->GetMaterialPropertiesTable(); |
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218 | |
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219 | if(aMaterialPropertiesTable){ |
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220 | |
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221 | G4MaterialPropertyVector* AttenuationLengthVector = |
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222 | aMaterialPropertiesTable->GetProperty("RAYLEIGH"); |
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223 | |
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224 | if(!AttenuationLengthVector){ |
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225 | |
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226 | if ((*theMaterialTable)[i]->GetName() == "Water") |
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227 | { |
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228 | // Call utility routine to Generate |
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229 | // Rayleigh Scattering Lengths |
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230 | |
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231 | DefaultWater = true; |
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232 | |
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233 | ScatteringLengths = |
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234 | RayleighAttenuationLengthGenerator(aMaterialPropertiesTable); |
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235 | } |
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236 | } |
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237 | } |
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238 | |
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239 | thePhysicsTable->insertAt(i,ScatteringLengths); |
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240 | } |
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241 | } |
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242 | |
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243 | // GetMeanFreePath() |
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244 | // ----------------- |
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245 | // |
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246 | G4double G4OpRayleigh::GetMeanFreePath(const G4Track& aTrack, |
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247 | G4double , |
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248 | G4ForceCondition* ) |
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249 | { |
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250 | const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle(); |
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251 | const G4Material* aMaterial = aTrack.GetMaterial(); |
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252 | |
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253 | G4double thePhotonEnergy = aParticle->GetTotalEnergy(); |
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254 | |
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255 | G4double AttenuationLength = DBL_MAX; |
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256 | |
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257 | if (aMaterial->GetName() == "Water" && DefaultWater){ |
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258 | |
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259 | G4bool isOutRange; |
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260 | |
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261 | AttenuationLength = |
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262 | (*thePhysicsTable)(aMaterial->GetIndex())-> |
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263 | GetValue(thePhotonEnergy, isOutRange); |
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264 | } |
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265 | else { |
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266 | |
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267 | G4MaterialPropertiesTable* aMaterialPropertyTable = |
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268 | aMaterial->GetMaterialPropertiesTable(); |
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269 | |
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270 | if(aMaterialPropertyTable){ |
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271 | G4MaterialPropertyVector* AttenuationLengthVector = |
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272 | aMaterialPropertyTable->GetProperty("RAYLEIGH"); |
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273 | if(AttenuationLengthVector){ |
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274 | AttenuationLength = AttenuationLengthVector -> |
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275 | GetProperty(thePhotonEnergy); |
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276 | } |
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277 | else{ |
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278 | // G4cout << "No Rayleigh scattering length specified" << G4endl; |
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279 | } |
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280 | } |
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281 | else{ |
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282 | // G4cout << "No Rayleigh scattering length specified" << G4endl; |
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283 | } |
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284 | } |
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285 | |
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286 | return AttenuationLength; |
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287 | } |
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288 | |
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289 | // RayleighAttenuationLengthGenerator() |
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290 | // ------------------------------------ |
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291 | // Private method to compute Rayleigh Scattering Lengths (for water) |
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292 | // |
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293 | G4PhysicsOrderedFreeVector* |
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294 | G4OpRayleigh::RayleighAttenuationLengthGenerator(G4MaterialPropertiesTable *aMPT) |
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295 | { |
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296 | // Physical Constants |
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297 | |
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298 | // isothermal compressibility of water |
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299 | G4double betat = 7.658e-23*m3/MeV; |
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300 | |
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301 | // K Boltzman |
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302 | G4double kboltz = 8.61739e-11*MeV/kelvin; |
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303 | |
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304 | // Temperature of water is 10 degrees celsius |
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305 | // conversion to kelvin: |
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306 | // TCelsius = TKelvin - 273.15 => 273.15 + 10 = 283.15 |
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307 | G4double temp = 283.15*kelvin; |
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308 | |
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309 | // Retrieve vectors for refraction index |
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310 | // and photon energy from the material properties table |
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311 | |
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312 | G4MaterialPropertyVector* Rindex = aMPT->GetProperty("RINDEX"); |
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313 | |
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314 | G4double refsq; |
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315 | G4double e; |
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316 | G4double xlambda; |
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317 | G4double c1, c2, c3, c4; |
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318 | G4double Dist; |
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319 | G4double refraction_index; |
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320 | |
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321 | G4PhysicsOrderedFreeVector *RayleighScatteringLengths = |
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322 | new G4PhysicsOrderedFreeVector(); |
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323 | |
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324 | if (Rindex ) { |
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325 | |
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326 | Rindex->ResetIterator(); |
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327 | |
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328 | while (++(*Rindex)) { |
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329 | |
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330 | e = (Rindex->GetPhotonEnergy()); |
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331 | |
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332 | refraction_index = Rindex->GetProperty(); |
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333 | refsq = refraction_index*refraction_index; |
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334 | xlambda = h_Planck*c_light/e; |
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335 | |
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336 | if (verboseLevel>0) { |
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337 | G4cout << Rindex->GetPhotonEnergy() << " MeV\t"; |
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338 | G4cout << xlambda << " mm\t"; |
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339 | } |
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340 | |
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341 | c1 = 1 / (6.0 * pi); |
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342 | c2 = std::pow((2.0 * pi / xlambda), 4); |
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343 | c3 = std::pow( ( (refsq - 1.0) * (refsq + 2.0) / 3.0 ), 2); |
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344 | c4 = betat * temp * kboltz; |
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345 | |
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346 | Dist = 1.0 / (c1*c2*c3*c4); |
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347 | |
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348 | if (verboseLevel>0) { |
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349 | G4cout << Dist << " mm" << G4endl; |
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350 | } |
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351 | RayleighScatteringLengths-> |
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352 | InsertValues(Rindex->GetPhotonEnergy(), Dist); |
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353 | } |
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354 | |
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355 | } |
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356 | |
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357 | return RayleighScatteringLengths; |
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358 | } |
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