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 | // File name: G4PiMinusStopMaterial |
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27 | // |
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28 | // Author: Maria Grazia Pia (pia@genova.infn.it) |
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29 | // |
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30 | // Creation date: 8 May 1998 |
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31 | // |
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32 | // ------------------------------------------------------------------- |
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33 | |
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34 | #include "G4ios.hh" |
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35 | |
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36 | #include "G4PiMinusStopMaterial.hh" |
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37 | |
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38 | #include <vector> |
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39 | |
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40 | #include "globals.hh" |
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41 | #include "Randomize.hh" |
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42 | #include "G4Proton.hh" |
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43 | #include "G4Neutron.hh" |
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44 | #include "G4PionMinus.hh" |
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45 | #include "G4ParticleTypes.hh" |
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46 | #include "G4ReactionKinematics.hh" |
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47 | #include "G4DynamicParticleVector.hh" |
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48 | #include "G4LorentzVector.hh" |
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49 | #include "G4NucleiPropertiesTable.hh" |
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50 | #include "G4PiMinusStopMaterial.hh" |
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51 | #include "G4DistributionGenerator.hh" |
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52 | |
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53 | |
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54 | // Constructor |
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55 | |
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56 | G4PiMinusStopMaterial::G4PiMinusStopMaterial() |
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57 | |
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58 | { |
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59 | _definitions = 0; |
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60 | _momenta = 0; |
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61 | _distributionE = 0; |
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62 | _distributionAngle = 0; |
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63 | |
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64 | } |
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65 | |
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66 | |
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67 | // Destructor |
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68 | |
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69 | G4PiMinusStopMaterial::~G4PiMinusStopMaterial() |
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70 | { |
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71 | // _definitions->clear(); |
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72 | if (_definitions != 0) delete _definitions; |
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73 | _definitions = 0; |
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74 | |
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75 | for(unsigned int i=0; i<_momenta->size(); i++) delete(*_momenta)[i]; |
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76 | if (_momenta != 0) delete _momenta; |
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77 | |
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78 | delete _distributionE; |
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79 | delete _distributionAngle; |
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80 | } |
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81 | |
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82 | std::vector<G4ParticleDefinition*>* G4PiMinusStopMaterial::DefinitionVector() |
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83 | { |
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84 | |
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85 | _definitions->push_back(G4Neutron::Neutron()); |
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86 | |
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87 | G4double ranflat = G4UniformRand(); |
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88 | if (ranflat < theR) |
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89 | { _definitions->push_back(G4Proton::Proton()); } |
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90 | else |
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91 | { _definitions->push_back(G4Neutron::Neutron()); } |
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92 | |
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93 | return _definitions; |
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94 | |
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95 | } |
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96 | |
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97 | std::vector<G4LorentzVector*>* G4PiMinusStopMaterial::P4Vector(const G4double binding, |
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98 | const G4double massNucleus) |
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99 | { |
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100 | |
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101 | // Generate energy of direct absorption products according to experimental data |
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102 | // The energy distribution of the two nucleons is assumed to be the same |
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103 | // for protons and neutrons |
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104 | |
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105 | |
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106 | G4double eKin1; |
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107 | G4double eKin2; |
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108 | G4double eRecoil; |
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109 | |
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110 | // Assume absorption on two nucleons |
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111 | G4int nNucleons = 2; |
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112 | G4double availableE = G4PionMinus::PionMinus()->GetPDGMass() - nNucleons * binding; |
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113 | G4LorentzVector p1; |
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114 | G4LorentzVector p2; |
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115 | |
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116 | do |
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117 | { |
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118 | G4double ranflat; |
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119 | G4double p; |
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120 | G4double energy; |
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121 | G4double mass; |
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122 | |
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123 | ranflat = G4UniformRand(); |
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124 | eKin1 = _distributionE->Generate(ranflat); |
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125 | mass = (*_definitions)[0]->GetPDGMass(); |
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126 | energy = eKin1 + mass; |
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127 | p = std::sqrt(energy*energy - mass*mass); |
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128 | G4double theta1 = pi*G4UniformRand(); |
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129 | G4double phi1 = GenerateAngle(2.*pi); |
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130 | p1 = MakeP4(p,theta1,phi1,energy); |
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131 | |
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132 | ranflat = G4UniformRand(); |
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133 | eKin2 = _distributionE->Generate(ranflat); |
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134 | mass = (*_definitions)[1]->GetPDGMass(); |
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135 | energy = eKin2 + mass; |
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136 | p = std::sqrt(energy*energy - mass*mass); |
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137 | ranflat = G4UniformRand(); |
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138 | G4double opAngle = _distributionAngle->Generate(ranflat); |
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139 | G4double theta2 = theta1 + opAngle; |
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140 | G4double phi2 = phi1 + opAngle; |
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141 | |
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142 | p2 = MakeP4(p,theta2,phi2,energy); |
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143 | |
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144 | G4double pNucleus = (p1.vect() + p2.vect()).mag(); |
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145 | eRecoil = std::sqrt(pNucleus*pNucleus + massNucleus*massNucleus) - massNucleus; |
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146 | |
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147 | // ---- Debug |
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148 | // G4cout << " ---- binding = " << binding << ", nucleus mass = " << massNucleus |
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149 | // << ", p nucleus = " << pNucleus << G4endl; |
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150 | // G4cout << "eKin1,2 " << eKin1 << " " << eKin2 << " eRecoil " << eRecoil |
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151 | // << " availableE " << availableE << G4endl; |
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152 | // ---- |
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153 | |
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154 | } while ((eKin1 + eKin2 + eRecoil) > availableE); |
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155 | |
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156 | _momenta->push_back(new G4LorentzVector(p1)); |
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157 | _momenta->push_back(new G4LorentzVector(p2)); |
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158 | |
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159 | return _momenta; |
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160 | |
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161 | } |
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162 | |
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163 | G4double G4PiMinusStopMaterial::GenerateAngle(G4double x) |
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164 | { |
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165 | G4double ranflat = G4UniformRand(); |
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166 | G4double value = ranflat * x; |
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167 | return value; |
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168 | } |
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169 | |
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170 | G4LorentzVector G4PiMinusStopMaterial::MakeP4(G4double p, G4double theta, G4double phi, G4double e) |
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171 | { |
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172 | // G4LorentzVector p4; |
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173 | G4double px = p * std::sin(theta) * std::cos(phi); |
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174 | G4double py = p * std::sin(theta) * std::sin(phi); |
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175 | G4double pz = p * std::cos(theta); |
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176 | G4LorentzVector p4(px,py,pz,e); |
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177 | return p4; |
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178 | } |
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179 | |
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180 | G4double G4PiMinusStopMaterial::RecoilEnergy(const G4double mass) |
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181 | { |
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182 | G4ThreeVector p(0.,0.,0.); |
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183 | |
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184 | for (unsigned int i = 0; i< _momenta->size(); i++) |
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185 | { |
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186 | p = p + (*_momenta)[i]->vect(); |
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187 | } |
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188 | G4double pNucleus = p.mag(); |
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189 | G4double eNucleus = std::sqrt(pNucleus*pNucleus + mass*mass); |
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190 | |
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191 | return eNucleus; |
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192 | } |
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193 | |
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194 | |
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195 | |
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196 | |
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198 | |
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199 | |
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200 | |
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202 | |
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