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 | #include "G4Absorber.hh" |
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27 | #include "G4KineticTrack.hh" |
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28 | #include "G4PionPlus.hh" |
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29 | #include "G4PionMinus.hh" |
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30 | #include "G4PionZero.hh" |
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31 | #include "G4Proton.hh" |
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32 | #include "G4Neutron.hh" |
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33 | |
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34 | #include "G4LorentzRotation.hh" |
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35 | |
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36 | G4Absorber::G4Absorber(G4double cutOnP) |
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37 | { |
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38 | theCutOnP = cutOnP; |
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39 | theAbsorbers = new G4KineticTrackVector; |
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40 | theProducts = new G4KineticTrackVector; |
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41 | } |
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42 | |
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43 | |
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44 | G4Absorber::~G4Absorber() |
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45 | { |
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46 | delete theAbsorbers; |
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47 | delete theProducts; |
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48 | } |
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49 | |
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50 | |
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51 | bool G4Absorber::WillBeAbsorbed(const G4KineticTrack & kt) |
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52 | { |
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53 | // FixMe: actually only for pions |
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54 | // if(kt.Get4Momentum().vect().mag() < theCutOnP) |
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55 | // Cut on kinetic Energy... |
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56 | if (kt.Get4Momentum().e() - kt.GetActualMass() < theCutOnP) |
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57 | { |
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58 | if(kt.GetDefinition() == G4PionPlus::PionPlus() || |
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59 | kt.GetDefinition() == G4PionZero::PionZero() || |
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60 | kt.GetDefinition() == G4PionMinus::PionMinus()) |
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61 | { |
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62 | return true; |
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63 | } |
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64 | } |
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65 | return false; |
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66 | } |
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67 | |
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68 | |
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69 | |
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70 | G4bool G4Absorber::Absorb(G4KineticTrack & kt, G4KineticTrackVector & tgt) |
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71 | { |
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72 | if(!FindAbsorbers(kt, tgt)) |
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73 | return false; |
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74 | return FindProducts(kt); |
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75 | } |
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76 | |
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77 | |
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78 | G4bool G4Absorber::FindAbsorbers(G4KineticTrack & kt, |
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79 | G4KineticTrackVector & tgt) |
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80 | { |
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81 | G4KineticTrack * kt1 = NULL; |
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82 | G4KineticTrack * kt2 = NULL; |
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83 | G4double dist1 = DBL_MAX; |
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84 | G4double dist2 = DBL_MAX; |
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85 | G4double charge1 = 0; |
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86 | G4double charge2 = 0; |
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87 | G4double charge0 = kt.GetDefinition()->GetPDGCharge(); |
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88 | G4ThreeVector pos = kt.GetPosition(); |
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89 | |
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90 | std::vector<G4KineticTrack *>::iterator iter; |
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91 | for(iter = tgt.begin(); iter != tgt.end(); ++iter) |
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92 | { |
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93 | G4KineticTrack * curr = *iter; |
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94 | G4double dist = (pos-curr->GetPosition()).mag(); |
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95 | if(dist >= dist2) |
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96 | continue; |
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97 | if(dist < dist1) |
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98 | { |
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99 | if(dist1 == DBL_MAX) // accept the candidate |
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100 | { |
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101 | kt1 = curr; |
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102 | charge1 = kt1->GetDefinition()->GetPDGCharge(); |
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103 | dist1 = dist; |
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104 | continue; |
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105 | } |
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106 | if(dist2 == DBL_MAX) // accept the candidate put kt1 in kt2 |
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107 | { |
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108 | kt2 = kt1; |
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109 | charge2 = charge1; |
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110 | dist2 = dist1; |
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111 | kt1 = curr; |
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112 | charge1 = kt1->GetDefinition()->GetPDGCharge(); |
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113 | dist1 = dist; |
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114 | continue; |
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115 | } |
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116 | // test the compatibility with charge conservation |
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117 | G4double charge = curr->GetDefinition()->GetPDGCharge(); |
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118 | if((charge0+charge1+charge < 0.) || |
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119 | (charge0+charge1+charge) > 2*eplus) |
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120 | { // incomatible: change kt1 with curr. |
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121 | kt1 = curr; |
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122 | charge1 = charge; |
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123 | dist1 = dist; |
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124 | } |
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125 | else |
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126 | { // compatible: change kt1 with curr and kt2 with kt1 |
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127 | kt2 = kt1; |
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128 | charge2 = charge1; |
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129 | dist2 = dist1; |
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130 | kt1 = curr; |
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131 | charge1 = charge; |
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132 | dist1 = dist; |
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133 | } |
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134 | continue; |
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135 | } |
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136 | // here if dist1 < dist < dist2 |
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137 | if(dist2 == DBL_MAX) // accept the candidate |
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138 | { |
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139 | kt2 = curr; |
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140 | charge2 = kt2->GetDefinition()->GetPDGCharge(); |
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141 | dist2 = dist; |
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142 | continue; |
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143 | } |
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144 | // test the compatibility with charge conservation |
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145 | G4double charge = curr->GetDefinition()->GetPDGCharge(); |
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146 | if((charge0+charge1+charge < 0.) || |
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147 | (charge0+charge1+charge) > 2*eplus) |
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148 | continue; // incomatible: do nothing |
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149 | // compatible: change kt2 with curr |
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150 | kt2 = curr; |
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151 | charge2 = charge; |
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152 | dist2 = dist; |
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153 | } |
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154 | |
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155 | theAbsorbers->clear(); // do not delete tracks in theAbsorbers vector! |
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156 | if((kt1 == NULL) || (kt2 == NULL)) |
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157 | return false; |
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158 | |
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159 | theAbsorbers->push_back(kt1); |
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160 | theAbsorbers->push_back(kt2); |
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161 | return true; |
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162 | } |
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163 | |
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164 | |
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165 | |
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166 | G4bool G4Absorber::FindProducts(G4KineticTrack & kt) |
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167 | { |
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168 | // Choose the products type |
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169 | G4ParticleDefinition * prod1; |
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170 | G4ParticleDefinition * prod2; |
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171 | G4KineticTrack * abs1 = (*theAbsorbers)[0]; |
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172 | G4KineticTrack * abs2 = (*theAbsorbers)[1]; |
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173 | |
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174 | G4double charge = kt.GetDefinition()->GetPDGCharge(); |
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175 | if(charge == eplus) |
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176 | { // a neutron become proton |
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177 | prod1 = G4Proton::Proton(); |
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178 | if(abs1->GetDefinition() == G4Neutron::Neutron()) |
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179 | prod2 = abs2->GetDefinition(); |
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180 | else |
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181 | prod2 = G4Proton::Proton(); |
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182 | } |
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183 | else if(charge == -eplus) |
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184 | { // a proton become neutron |
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185 | prod1 = G4Neutron::Neutron(); |
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186 | if(abs1->GetDefinition() == G4Proton::Proton()) |
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187 | prod2 = abs2->GetDefinition(); |
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188 | else |
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189 | prod2 = G4Neutron::Neutron(); |
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190 | } |
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191 | else // charge = 0: leave particle types unchenged |
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192 | { |
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193 | prod1 = abs1->GetDefinition(); |
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194 | prod2 = abs2->GetDefinition(); |
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195 | } |
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196 | |
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197 | // Translate to the CMS frame |
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198 | G4LorentzVector momLab = kt.Get4Momentum()+abs1->Get4Momentum()+ |
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199 | abs2->Get4Momentum(); |
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200 | G4LorentzRotation toCMSFrame((-1)*momLab.boostVector()); |
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201 | G4LorentzRotation toLabFrame(momLab.boostVector()); |
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202 | G4LorentzVector momCMS = toCMSFrame*momLab; |
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203 | |
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204 | // Evaluate the final momentum of products |
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205 | G4double m1 = prod1->GetPDGMass(); |
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206 | G4double m2 = prod2->GetPDGMass(); |
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207 | G4double e0 = momCMS.e(); |
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208 | G4double squareP = (e0*e0*e0*e0-2*e0*e0*(m1*m1+m2*m2)+ |
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209 | (m2*m2-m1*m1)*(m2*m2-m1*m1))/(4*e0*e0); |
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210 | // if(squareP < 0) // should never happen |
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211 | // squareP = 0; |
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212 | G4ThreeVector mom1CMS = GetRandomDirection(); |
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213 | mom1CMS = std::sqrt(squareP)*mom1CMS; |
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214 | G4LorentzVector final4Mom1CMS(mom1CMS, std::sqrt(squareP+m1*m1)); |
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215 | G4LorentzVector final4Mom2CMS((-1)*mom1CMS, std::sqrt(squareP+m2*m2)); |
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216 | |
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217 | // Go back to the lab frame |
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218 | G4LorentzVector mom1 = toLabFrame*final4Mom1CMS; |
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219 | G4LorentzVector mom2 = toLabFrame*final4Mom2CMS; |
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220 | |
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221 | // ------ debug |
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222 | /* |
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223 | G4LorentzVector temp = mom1+mom2; |
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224 | |
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225 | cout << (1/MeV)*momLab.x() << " " << (1/MeV)*momLab.y() << " " |
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226 | << (1/MeV)*momLab.z() << " " << (1/MeV)*momLab.t() << " " |
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227 | << (1/MeV)*momLab.vect().mag() << " " << (1/MeV)*momLab.mag() << " " |
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228 | << (1/MeV)*temp.x() << " " << (1/MeV)*temp.y() << " " |
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229 | << (1/MeV)*temp.z() << " " << (1/MeV)*temp.t() << " " |
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230 | << (1/MeV)*temp.vect().mag() << " " << (1/MeV)*temp.mag() << " " |
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231 | << (1/MeV)*std::sqrt(squareP) << endl; |
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232 | |
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233 | */ |
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234 | // ------ end debug |
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235 | |
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236 | // Build two new kinetic tracks and add to products |
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237 | G4KineticTrack * kt1 = new G4KineticTrack(prod1, 0., abs1->GetPosition(), |
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238 | mom1); |
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239 | G4KineticTrack * kt2 = new G4KineticTrack(prod2, 0., abs2->GetPosition(), |
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240 | mom2); |
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241 | // ------ debug |
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242 | /* |
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243 | G4LorentzVector initialMom1 = abs1->Get4Momentum(); |
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244 | G4LorentzVector initialMom2 = abs2->Get4Momentum(); |
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245 | G4LorentzVector pion4MomCMS = toCMSFrame*kt.Get4Momentum(); |
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246 | cout << (1/MeV)*initialMom1.x() << " " << (1/MeV)*initialMom1.y() << " " |
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247 | << (1/MeV)*initialMom1.z() << " " << (1/MeV)*initialMom1.e() << " " |
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248 | << (1/MeV)*initialMom1.vect().mag() << " " |
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249 | << (1/MeV)*initialMom2.x() << " " << (1/MeV)*initialMom2.y() << " " |
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250 | << (1/MeV)*initialMom2.z() << " " << (1/MeV)*initialMom2.e() << " " |
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251 | << (1/MeV)*initialMom2.vect().mag() << " " |
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252 | << (1/MeV)*mom1.x() << " " << (1/MeV)*mom1.y() << " " |
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253 | << (1/MeV)*mom1.z() << " " << (1/MeV)*mom1.e() << " " |
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254 | << (1/MeV)*mom1.vect().mag() << " " |
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255 | << (1/MeV)*mom2.x() << " " << (1/MeV)*mom2.y() << " " |
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256 | << (1/MeV)*mom2.z() << " " << (1/MeV)*mom2.e() << " " |
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257 | << (1/MeV)*mom2.vect().mag() << " " |
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258 | << (1/MeV)*pion4MomCMS.x() << " " << (1/MeV)*pion4MomCMS.y() << " " |
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259 | << (1/MeV)*pion4MomCMS.z() << " " << (1/MeV)*pion4MomCMS.e() << " " |
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260 | << (1/MeV)*pion4MomCMS.vect().mag() << " " |
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261 | << (1/MeV)*final4Mom1CMS.x() << " " << (1/MeV)*final4Mom1CMS.y() << " " |
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262 | << (1/MeV)*final4Mom1CMS.z() << " " << (1/MeV)*final4Mom1CMS.e() << " " |
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263 | << (1/MeV)*final4Mom1CMS.vect().mag() << " " |
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264 | << (1/MeV)*final4Mom2CMS.x() << " " << (1/MeV)*final4Mom2CMS.y() << " " |
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265 | << (1/MeV)*final4Mom2CMS.z() << " " << (1/MeV)*final4Mom2CMS.e() << " " |
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266 | << (1/MeV)*final4Mom2CMS.vect().mag() << endl; |
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267 | */ |
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268 | // ------ end debug |
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269 | |
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270 | theProducts->clear(); |
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271 | theProducts->push_back(kt1); |
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272 | theProducts->push_back(kt2); |
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273 | return true; |
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274 | } |
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275 | |
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276 | |
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277 | |
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278 | G4ThreeVector G4Absorber::GetRandomDirection() |
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279 | { |
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280 | G4double theta = 2.0*G4UniformRand()-1.0; |
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281 | theta = std::acos(theta); |
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282 | G4double phi = G4UniformRand()*2*pi; |
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283 | G4ThreeVector direction(std::sin(theta)*std::cos(phi), std::sin(theta)*std::sin(phi), std::cos(theta)); |
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284 | return direction; |
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285 | } |
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286 | |
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287 | |
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288 | |
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289 | |
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290 | |
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291 | |
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292 | |
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