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 | // G4NeutronCaptureAtRest physics process |
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27 | // Larry Felawka (TRIUMF), April 1998 |
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28 | //--------------------------------------------------------------------- |
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29 | |
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30 | #include "G4NeutronCaptureAtRest.hh" |
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31 | #include "G4DynamicParticle.hh" |
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32 | #include "G4ParticleTypes.hh" |
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33 | #include "Randomize.hh" |
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34 | #include <string.h> |
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35 | #include <cmath> |
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36 | #include <stdio.h> |
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37 | |
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38 | #define MAX_SECONDARIES 100 |
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39 | |
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40 | // constructor |
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41 | |
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42 | G4NeutronCaptureAtRest::G4NeutronCaptureAtRest(const G4String& processName, |
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43 | G4ProcessType aType ) : |
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44 | G4VRestProcess (processName, aType), // initialization |
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45 | massProton(G4Proton::Proton()->GetPDGMass()/GeV), |
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46 | massNeutron(G4Neutron::Neutron()->GetPDGMass()/GeV), |
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47 | massElectron(G4Electron::Electron()->GetPDGMass()/GeV), |
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48 | massDeuteron(G4Deuteron::Deuteron()->GetPDGMass()/GeV), |
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49 | massAlpha(G4Alpha::Alpha()->GetPDGMass()/GeV), |
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50 | pdefGamma(G4Gamma::Gamma()), |
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51 | pdefNeutron(G4Neutron::Neutron()) |
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52 | { |
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53 | if (verboseLevel>0) { |
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54 | G4cout << GetProcessName() << " is created "<< G4endl; |
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55 | } |
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56 | SetProcessSubType(fHadronAtRest); |
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57 | pv = new G4GHEKinematicsVector [MAX_SECONDARIES+1]; |
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58 | eve = new G4GHEKinematicsVector [MAX_SECONDARIES]; |
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59 | gkin = new G4GHEKinematicsVector [MAX_SECONDARIES]; |
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60 | |
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61 | } |
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62 | |
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63 | // destructor |
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64 | |
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65 | G4NeutronCaptureAtRest::~G4NeutronCaptureAtRest() |
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66 | { |
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67 | delete [] pv; |
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68 | delete [] eve; |
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69 | delete [] gkin; |
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70 | } |
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71 | |
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72 | |
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73 | // methods............................................................................. |
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74 | |
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75 | G4bool G4NeutronCaptureAtRest::IsApplicable( |
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76 | const G4ParticleDefinition& particle |
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77 | ) |
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78 | { |
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79 | return ( &particle == pdefNeutron ); |
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80 | |
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81 | } |
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82 | |
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83 | // Warning - this method may be optimized away if made "inline" |
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84 | G4int G4NeutronCaptureAtRest::GetNumberOfSecondaries() |
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85 | { |
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86 | return ( ngkine ); |
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87 | |
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88 | } |
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89 | |
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90 | // Warning - this method may be optimized away if made "inline" |
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91 | G4GHEKinematicsVector* G4NeutronCaptureAtRest::GetSecondaryKinematics() |
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92 | { |
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93 | return ( &gkin[0] ); |
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94 | |
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95 | } |
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96 | |
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97 | G4double G4NeutronCaptureAtRest::AtRestGetPhysicalInteractionLength( |
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98 | const G4Track& track, |
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99 | G4ForceCondition* condition |
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100 | ) |
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101 | { |
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102 | // beggining of tracking |
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103 | ResetNumberOfInteractionLengthLeft(); |
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104 | |
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105 | // condition is set to "Not Forced" |
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106 | *condition = NotForced; |
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107 | |
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108 | // get mean life time |
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109 | currentInteractionLength = GetMeanLifeTime(track, condition); |
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110 | |
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111 | if ((currentInteractionLength <0.0) || (verboseLevel>2)){ |
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112 | G4cout << "G4NeutronCaptureAtRestProcess::AtRestGetPhysicalInteractionLength "; |
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113 | G4cout << "[ " << GetProcessName() << "]" <<G4endl; |
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114 | track.GetDynamicParticle()->DumpInfo(); |
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115 | G4cout << " in Material " << track.GetMaterial()->GetName() <<G4endl; |
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116 | G4cout << "MeanLifeTime = " << currentInteractionLength/ns << "[ns]" <<G4endl; |
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117 | } |
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118 | |
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119 | return theNumberOfInteractionLengthLeft * currentInteractionLength; |
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120 | |
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121 | } |
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122 | |
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123 | G4VParticleChange* G4NeutronCaptureAtRest::AtRestDoIt( |
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124 | const G4Track& track, |
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125 | const G4Step& |
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126 | ) |
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127 | // |
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128 | // Handles Neutrons at rest; a Neutron can either create secondaries or |
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129 | // do nothing (in which case it should be sent back to decay-handling |
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130 | // section |
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131 | // |
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132 | { |
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133 | |
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134 | // Initialize ParticleChange |
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135 | // all members of G4VParticleChange are set to equal to |
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136 | // corresponding member in G4Track |
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137 | |
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138 | aParticleChange.Initialize(track); |
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139 | |
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140 | // Store some global quantities that depend on current material and particle |
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141 | |
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142 | globalTime = track.GetGlobalTime()/s; |
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143 | G4Material * aMaterial = track.GetMaterial(); |
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144 | const G4int numberOfElements = aMaterial->GetNumberOfElements(); |
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145 | const G4ElementVector* theElementVector = aMaterial->GetElementVector(); |
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146 | |
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147 | const G4double* theAtomicNumberDensity = aMaterial->GetAtomicNumDensityVector(); |
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148 | G4double normalization = 0; |
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149 | for ( G4int i1=0; i1 < numberOfElements; i1++ ) |
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150 | { |
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151 | normalization += theAtomicNumberDensity[i1] ; // change when nucleon specific |
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152 | // probabilities are included. |
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153 | } |
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154 | G4double runningSum= 0.; |
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155 | G4double random = G4UniformRand()*normalization; |
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156 | for ( G4int i2=0; i2 < numberOfElements; i2++ ) |
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157 | { |
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158 | runningSum += theAtomicNumberDensity[i2]; // change when nucleon specific |
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159 | // probabilities are included. |
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160 | if (random<=runningSum) |
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161 | { |
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162 | targetCharge = G4double((*theElementVector)[i2]->GetZ()); |
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163 | targetAtomicMass = (*theElementVector)[i2]->GetN(); |
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164 | } |
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165 | } |
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166 | if (random>runningSum) |
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167 | { |
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168 | targetCharge = G4double((*theElementVector)[numberOfElements-1]->GetZ()); |
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169 | targetAtomicMass = (*theElementVector)[numberOfElements-1]->GetN(); |
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170 | |
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171 | } |
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172 | |
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173 | if (verboseLevel>1) { |
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174 | G4cout << "G4NeutronCaptureAtRest::AtRestDoIt is invoked " <<G4endl; |
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175 | } |
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176 | |
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177 | G4ParticleMomentum momentum; |
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178 | G4float localtime; |
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179 | |
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180 | G4ThreeVector position = track.GetPosition(); |
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181 | |
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182 | GenerateSecondaries(); // Generate secondaries |
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183 | |
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184 | aParticleChange.SetNumberOfSecondaries( ngkine ); |
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185 | |
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186 | for ( G4int isec = 0; isec < ngkine; isec++ ) { |
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187 | G4DynamicParticle* aNewParticle = new G4DynamicParticle; |
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188 | aNewParticle->SetDefinition( gkin[isec].GetParticleDef() ); |
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189 | aNewParticle->SetMomentum( gkin[isec].GetMomentum() * GeV ); |
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190 | |
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191 | localtime = globalTime + gkin[isec].GetTOF(); |
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192 | |
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193 | G4Track* aNewTrack = new G4Track( aNewParticle, localtime*s, position ); |
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194 | aNewTrack->SetTouchableHandle(track.GetTouchableHandle()); |
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195 | aParticleChange.AddSecondary( aNewTrack ); |
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196 | |
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197 | } |
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198 | |
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199 | aParticleChange.ProposeLocalEnergyDeposit( 0.0*GeV ); |
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200 | |
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201 | aParticleChange.ProposeTrackStatus(fStopAndKill); // Kill the incident Neutron |
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202 | |
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203 | // clear InteractionLengthLeft |
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204 | |
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205 | ResetNumberOfInteractionLengthLeft(); |
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206 | |
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207 | return &aParticleChange; |
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208 | |
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209 | } |
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210 | |
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211 | |
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212 | void G4NeutronCaptureAtRest::GenerateSecondaries() |
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213 | { |
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214 | static G4int index; |
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215 | static G4int l; |
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216 | static G4int nopt; |
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217 | static G4int i; |
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218 | static G4ParticleDefinition* jnd; |
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219 | |
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220 | for (i = 1; i <= MAX_SECONDARIES; ++i) { |
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221 | pv[i].SetZero(); |
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222 | } |
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223 | |
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224 | ngkine = 0; // number of generated secondary particles |
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225 | ntot = 0; |
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226 | result.SetZero(); |
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227 | result.SetMass( massNeutron ); |
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228 | result.SetKineticEnergyAndUpdate( 0. ); |
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229 | result.SetTOF( 0. ); |
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230 | result.SetParticleDef( pdefNeutron ); |
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231 | |
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232 | NeutronCapture(&nopt); |
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233 | |
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234 | // *** CHECK WHETHER THERE ARE NEW PARTICLES GENERATED *** |
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235 | if (ntot != 0 || result.GetParticleDef() != pdefNeutron) { |
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236 | // *** CURRENT PARTICLE IS NOT THE SAME AS IN THE BEGINNING OR/AND *** |
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237 | // *** ONE OR MORE SECONDARIES HAVE BEEN GENERATED *** |
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238 | |
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239 | // --- INITIAL PARTICLE TYPE HAS BEEN CHANGED ==> PUT NEW TYPE ON --- |
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240 | // --- THE GEANT TEMPORARY STACK --- |
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241 | |
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242 | // --- PUT PARTICLE ON THE STACK --- |
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243 | gkin[0] = result; |
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244 | gkin[0].SetTOF( result.GetTOF() * 5e-11 ); |
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245 | ngkine = 1; |
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246 | |
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247 | // --- ALL QUANTITIES ARE TAKEN FROM THE GHEISHA STACK WHERE THE --- |
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248 | // --- CONVENTION IS THE FOLLOWING --- |
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249 | |
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250 | // --- ONE OR MORE SECONDARIES HAVE BEEN GENERATED --- |
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251 | for (l = 1; l <= ntot; ++l) { |
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252 | index = l - 1; |
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253 | jnd = eve[index].GetParticleDef(); |
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254 | |
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255 | // --- ADD PARTICLE TO THE STACK IF STACK NOT YET FULL --- |
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256 | if (ngkine < MAX_SECONDARIES) { |
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257 | gkin[ngkine] = eve[index]; |
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258 | gkin[ngkine].SetTOF( eve[index].GetTOF() * 5e-11 ); |
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259 | ++ngkine; |
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260 | } |
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261 | } |
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262 | } |
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263 | else { |
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264 | // --- NO SECONDARIES GENERATED AND PARTICLE IS STILL THE SAME --- |
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265 | // --- ==> COPY EVERYTHING BACK IN THE CURRENT GEANT STACK --- |
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266 | ngkine = 0; |
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267 | ntot = 0; |
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268 | globalTime += result.GetTOF() * G4float(5e-11); |
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269 | } |
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270 | |
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271 | // --- LIMIT THE VALUE OF NGKINE IN CASE OF OVERFLOW --- |
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272 | ngkine = G4int(std::min(ngkine,G4int(MAX_SECONDARIES))); |
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273 | |
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274 | } // GenerateSecondaries |
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275 | |
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276 | |
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277 | void G4NeutronCaptureAtRest::Normal(G4float *ran) |
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278 | { |
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279 | static G4int i; |
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280 | |
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281 | // *** NVE 14-APR-1988 CERN GENEVA *** |
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282 | // ORIGIN : H.FESEFELDT (27-OCT-1983) |
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283 | |
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284 | *ran = G4float(-6.); |
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285 | for (i = 1; i <= 12; ++i) { |
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286 | *ran += G4UniformRand(); |
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287 | } |
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288 | |
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289 | } // Normal |
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290 | |
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291 | |
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292 | void G4NeutronCaptureAtRest::NeutronCapture(G4int *nopt) |
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293 | { |
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294 | static G4int nt; |
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295 | static G4float xp, pcm; |
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296 | static G4float ran; |
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297 | |
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298 | // *** ROUTINE FOR CAPTURE OF NEUTRAL BARYONS *** |
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299 | // *** NVE 04-MAR-1988 CERN GENEVA *** |
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300 | // ORIGIN : H.FESEFELDT (02-DEC-1986) |
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301 | |
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302 | *nopt = 1; |
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303 | pv[1] = result; |
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304 | pv[2].SetZero(); |
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305 | pv[2].SetMass( AtomAs(targetAtomicMass, targetCharge) ); |
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306 | pv[2].SetMomentumAndUpdate( 0., 0., 0. ); |
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307 | pv[2].SetTOF( result.GetTOF() ); |
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308 | pv[2].SetParticleDef( NULL ); |
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309 | pv[MAX_SECONDARIES].Add( pv[1], pv[2] ); |
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310 | pv[MAX_SECONDARIES].SetMomentum( -pv[MAX_SECONDARIES].GetMomentum().x(), -pv[MAX_SECONDARIES].GetMomentum().y(), -pv[MAX_SECONDARIES].GetMomentum().z() ); |
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311 | pv[MAX_SECONDARIES].SetParticleDef( NULL ); |
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312 | Normal(&ran); |
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313 | pcm = ran * G4float(.001) + G4float(.0065); |
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314 | ran = G4UniformRand(); |
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315 | result.SetTOF( result.GetTOF() - std::log(ran) * G4float(480.) ); |
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316 | pv[3].SetZero(); |
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317 | pv[3].SetMass( 0. ); |
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318 | pv[3].SetKineticEnergyAndUpdate( pcm ); |
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319 | pv[3].SetTOF( result.GetTOF() ); |
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320 | pv[3].SetParticleDef( pdefGamma ); |
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321 | pv[3].Lor( pv[3], pv[MAX_SECONDARIES] ); |
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322 | nt = 3; |
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323 | xp = G4float(.008) - pcm; |
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324 | if (xp >= G4float(0.)) { |
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325 | nt = 4; |
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326 | pv[4].SetZero(); |
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327 | pv[4].SetMass( 0. ); |
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328 | pv[4].SetKineticEnergyAndUpdate( xp ); |
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329 | pv[4].SetTOF( result.GetTOF() ); |
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330 | pv[4].SetParticleDef( pdefGamma ); |
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331 | pv[4].Lor( pv[4], pv[MAX_SECONDARIES] ); |
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332 | } |
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333 | result = pv[3]; |
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334 | if (nt == 4) { |
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335 | if (ntot < MAX_SECONDARIES-1) { |
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336 | eve[ntot++] = pv[4]; |
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337 | } |
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338 | } |
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339 | |
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340 | } // NeutronCapture |
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341 | |
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342 | |
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343 | G4double G4NeutronCaptureAtRest::AtomAs(G4float a, G4float z) |
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344 | { |
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345 | G4float ret_val; |
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346 | G4double d__1, d__2; |
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347 | |
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348 | static G4double aa; |
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349 | static G4int ia, iz; |
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350 | static G4double zz; |
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351 | static G4float rma, rmd; |
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352 | static G4int ipp; |
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353 | static G4float rmn, rmp; |
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354 | static G4int izz; |
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355 | static G4float rmel; |
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356 | static G4double mass; |
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357 | |
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358 | // *** DETERMINATION OF THE ATOMIC MASS *** |
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359 | // *** NVE 19-MAY-1988 CERN GENEVA *** |
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360 | // ORIGIN : H.FESEFELDT (02-DEC-1986) |
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361 | |
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362 | // --- GET ATOMIC (= ELECTRONS INCL.) MASSES (IN MEV) FROM RMASS ARRAY --- |
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363 | // --- ELECTRON --- |
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364 | rmel = massElectron * G4float(1e3); |
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365 | // --- PROTON --- |
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366 | rmp = massProton * G4float(1e3); |
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367 | // --- NEUTRON --- |
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368 | rmn = massNeutron * G4float(1e3); |
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369 | // --- DEUTERON --- |
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370 | rmd = massDeuteron * G4float(1e3) + rmel; |
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371 | // --- ALPHA --- |
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372 | rma = massAlpha * G4float(1e3) + rmel * G4float(2.); |
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373 | |
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374 | ret_val = G4float(0.); |
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375 | aa = a * 1.; |
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376 | zz = z * 1.; |
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377 | ia = G4int(a + G4float(.5)); |
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378 | if (ia < 1) { |
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379 | return ret_val; |
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380 | } |
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381 | iz = G4int(z + G4float(.5)); |
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382 | if (iz < 0 || iz > ia) { |
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383 | return ret_val; |
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384 | } |
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385 | mass = 0.; |
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386 | if (ia == 1) { |
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387 | if (iz == 0) { |
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388 | mass = rmn; |
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389 | } |
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390 | else if (iz == 1) { |
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391 | mass = rmp + rmel; |
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392 | } |
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393 | } |
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394 | else if (ia == 2 && iz == 1) { |
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395 | mass = rmd; |
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396 | } |
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397 | else if (ia == 4 && iz == 2) { |
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398 | mass = rma; |
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399 | } |
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400 | else if ( (ia == 2 && iz != 1) || ia == 3 || (ia == 4 && iz != 2) || ia > 4) { |
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401 | d__1 = aa / G4float(2.) - zz; |
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402 | d__2 = zz; |
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403 | mass = (aa - zz) * rmn + zz * rmp + zz * rmel - aa * G4float(15.67) + |
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404 | std::pow(aa, .6666667) * G4float(17.23) + d__1 * d__1 * G4float(93.15) / aa + |
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405 | d__2 * d__2 * G4float(.6984523) / std::pow(aa, .3333333); |
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406 | ipp = (ia - iz) % 2; |
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407 | izz = iz % 2; |
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408 | if (ipp == izz) { |
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409 | mass += (ipp + izz - 1) * G4float(12.) * std::pow(aa, -.5); |
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410 | } |
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411 | } |
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412 | ret_val = mass * G4float(.001); |
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413 | return ret_val; |
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414 | |
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415 | } // AtomAs |
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