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 | // |
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28 | // original by H.P. Wellisch |
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29 | // modified by J.L. Chuma, TRIUMF, 19-Nov-1996 |
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30 | // last modified: 27-Mar-1997 |
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31 | // J.P.Wellisch: 23-Apr-97: minor simplifications |
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32 | // modified by J.L.Chuma 24-Jul-97 to set the total momentum in Cinema and |
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33 | // EvaporationEffects |
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34 | // modified by J.L.Chuma 21-Oct-97 put std::abs() around the totalE^2-mass^2 |
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35 | // in calculation of total momentum in |
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36 | // Cinema and EvaporationEffects |
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37 | // Chr. Volcker, 10-Nov-1997: new methods and class variables. |
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38 | // HPW added utilities for low energy neutron transport. (12.04.1998) |
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39 | // M.G. Pia, 2 Oct 1998: modified GetFermiMomentum to avoid memory leaks |
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40 | |
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41 | #include "G4Nucleus.hh" |
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42 | #include "G4NucleiProperties.hh" |
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43 | #include "Randomize.hh" |
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44 | #include "G4HadronicException.hh" |
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45 | |
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46 | G4Nucleus::G4Nucleus() |
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47 | { |
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48 | pnBlackTrackEnergy = 0.0; |
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49 | dtaBlackTrackEnergy = 0.0; |
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50 | pnBlackTrackEnergyfromAnnihilation = 0.0; |
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51 | dtaBlackTrackEnergyfromAnnihilation = 0.0; |
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52 | excitationEnergy = 0.0; |
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53 | momentum = G4ThreeVector(0.,0.,0.); |
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54 | fermiMomentum = 1.52*hbarc/fermi; |
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55 | theTemp = 293.16*kelvin; |
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56 | } |
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57 | |
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58 | G4Nucleus::G4Nucleus( const G4double A, const G4double Z ) |
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59 | { |
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60 | SetParameters( A, Z ); |
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61 | pnBlackTrackEnergy = 0.0; |
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62 | dtaBlackTrackEnergy = 0.0; |
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63 | pnBlackTrackEnergyfromAnnihilation = 0.0; |
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64 | dtaBlackTrackEnergyfromAnnihilation = 0.0; |
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65 | excitationEnergy = 0.0; |
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66 | momentum = G4ThreeVector(0.,0.,0.); |
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67 | fermiMomentum = 1.52*hbarc/fermi; |
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68 | theTemp = 293.16*kelvin; |
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69 | } |
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70 | |
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71 | G4Nucleus::G4Nucleus( const G4Material *aMaterial ) |
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72 | { |
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73 | ChooseParameters( aMaterial ); |
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74 | pnBlackTrackEnergy = 0.0; |
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75 | dtaBlackTrackEnergy = 0.0; |
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76 | pnBlackTrackEnergyfromAnnihilation = 0.0; |
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77 | dtaBlackTrackEnergyfromAnnihilation = 0.0; |
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78 | excitationEnergy = 0.0; |
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79 | momentum = G4ThreeVector(0.,0.,0.); |
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80 | fermiMomentum = 1.52*hbarc/fermi; |
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81 | theTemp = aMaterial->GetTemperature(); |
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82 | } |
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83 | |
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84 | G4Nucleus::~G4Nucleus() {} |
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85 | |
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86 | G4ReactionProduct G4Nucleus:: |
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87 | GetBiasedThermalNucleus(G4double aMass, G4ThreeVector aVelocity, G4double temp) const |
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88 | { |
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89 | G4double velMag = aVelocity.mag(); |
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90 | G4ReactionProduct result; |
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91 | G4double value = 0; |
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92 | G4double random = 1; |
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93 | G4double norm = 3.*std::sqrt(k_Boltzmann*temp*aMass*G4Neutron::Neutron()->GetPDGMass()); |
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94 | norm /= G4Neutron::Neutron()->GetPDGMass(); |
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95 | norm *= 5.; |
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96 | norm += velMag; |
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97 | norm /= velMag; |
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98 | while(value/norm<random) |
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99 | { |
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100 | result = GetThermalNucleus(aMass, temp); |
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101 | G4ThreeVector targetVelocity = 1./result.GetMass()*result.GetMomentum(); |
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102 | value = (targetVelocity+aVelocity).mag()/velMag; |
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103 | random = G4UniformRand(); |
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104 | } |
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105 | return result; |
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106 | } |
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107 | |
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108 | G4ReactionProduct G4Nucleus::GetThermalNucleus(G4double targetMass, G4double temp) const |
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109 | { |
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110 | G4double currentTemp = temp; |
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111 | if(currentTemp < 0) currentTemp = theTemp; |
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112 | G4ReactionProduct theTarget; |
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113 | theTarget.SetMass(targetMass*G4Neutron::Neutron()->GetPDGMass()); |
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114 | G4double px, py, pz; |
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115 | px = GetThermalPz(theTarget.GetMass(), currentTemp); |
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116 | py = GetThermalPz(theTarget.GetMass(), currentTemp); |
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117 | pz = GetThermalPz(theTarget.GetMass(), currentTemp); |
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118 | theTarget.SetMomentum(px, py, pz); |
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119 | G4double tMom = std::sqrt(px*px+py*py+pz*pz); |
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120 | G4double tEtot = std::sqrt((tMom+theTarget.GetMass())* |
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121 | (tMom+theTarget.GetMass())- |
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122 | 2.*tMom*theTarget.GetMass()); |
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123 | if(1-tEtot/theTarget.GetMass()>0.001) |
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124 | { |
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125 | theTarget.SetTotalEnergy(tEtot); |
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126 | } |
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127 | else |
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128 | { |
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129 | theTarget.SetKineticEnergy(tMom*tMom/(2.*theTarget.GetMass())); |
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130 | } |
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131 | return theTarget; |
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132 | } |
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133 | |
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134 | void |
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135 | G4Nucleus::ChooseParameters( const G4Material *aMaterial ) |
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136 | { |
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137 | G4double random = G4UniformRand(); |
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138 | G4double sum = 0; |
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139 | const G4ElementVector *theElementVector = aMaterial->GetElementVector(); |
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140 | unsigned int i; |
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141 | for(i=0; i<aMaterial->GetNumberOfElements(); ++i ) |
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142 | { |
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143 | sum += aMaterial->GetAtomicNumDensityVector()[i]; |
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144 | } |
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145 | G4double running = 0; |
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146 | for(i=0; i<aMaterial->GetNumberOfElements(); ++i ) |
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147 | { |
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148 | running += aMaterial->GetAtomicNumDensityVector()[i]; |
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149 | if( running/sum > random ) { |
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150 | aEff = (*theElementVector)[i]->GetA()*mole/g; |
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151 | zEff = (*theElementVector)[i]->GetZ(); |
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152 | break; |
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153 | } |
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154 | } |
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155 | } |
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156 | |
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157 | void |
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158 | G4Nucleus::SetParameters( const G4double A, const G4double Z ) |
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159 | { |
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160 | G4int myZ = G4int(Z + 0.5); |
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161 | G4int myA = G4int(A + 0.5); |
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162 | if( myA<1 || myZ<0 || myZ>myA ) |
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163 | { |
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164 | throw G4HadronicException(__FILE__, __LINE__, |
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165 | "G4Nucleus::SetParameters called with non-physical parameters"); |
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166 | } |
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167 | aEff = A; // atomic weight |
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168 | zEff = Z; // atomic number |
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169 | } |
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170 | |
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171 | G4DynamicParticle * |
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172 | G4Nucleus::ReturnTargetParticle() const |
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173 | { |
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174 | // choose a proton or a neutron as the target particle |
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175 | |
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176 | G4DynamicParticle *targetParticle = new G4DynamicParticle; |
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177 | if( G4UniformRand() < zEff/aEff ) |
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178 | targetParticle->SetDefinition( G4Proton::Proton() ); |
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179 | else |
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180 | targetParticle->SetDefinition( G4Neutron::Neutron() ); |
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181 | return targetParticle; |
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182 | } |
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183 | |
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184 | G4double |
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185 | G4Nucleus::AtomicMass( const G4double A, const G4double Z ) const |
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186 | { |
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187 | // Now returns (atomic mass - electron masses) |
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188 | return G4NucleiProperties::GetNuclearMass(A, Z); |
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189 | } |
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190 | |
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191 | G4double |
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192 | G4Nucleus::GetThermalPz( const G4double mass, const G4double temp ) const |
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193 | { |
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194 | G4double result = G4RandGauss::shoot(); |
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195 | result *= std::sqrt(k_Boltzmann*temp*mass); // Das ist impuls (Pz), |
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196 | // nichtrelativistische rechnung |
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197 | // Maxwell verteilung angenommen |
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198 | return result; |
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199 | } |
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200 | |
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201 | G4double |
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202 | G4Nucleus::EvaporationEffects( G4double kineticEnergy ) |
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203 | { |
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204 | // derived from original FORTRAN code EXNU by H. Fesefeldt (10-Dec-1986) |
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205 | // |
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206 | // Nuclear evaporation as function of atomic number |
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207 | // and kinetic energy (MeV) of primary particle |
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208 | // |
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209 | // returns kinetic energy (MeV) |
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210 | // |
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211 | if( aEff < 1.5 ) |
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212 | { |
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213 | pnBlackTrackEnergy = dtaBlackTrackEnergy = 0.0; |
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214 | return 0.0; |
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215 | } |
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216 | G4double ek = kineticEnergy/GeV; |
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217 | G4float ekin = std::min( 4.0, std::max( 0.1, ek ) ); |
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218 | const G4float atno = std::min( 120., aEff ); |
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219 | const G4float gfa = 2.0*((aEff-1.0)/70.)*std::exp(-(aEff-1.0)/70.); |
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220 | // |
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221 | // 0.35 value at 1 GeV |
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222 | // 0.05 value at 0.1 GeV |
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223 | // |
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224 | G4float cfa = std::max( 0.15, 0.35 + ((0.35-0.05)/2.3)*std::log(ekin) ); |
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225 | G4float exnu = 7.716 * cfa * std::exp(-cfa) |
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226 | * ((atno-1.0)/120.)*std::exp(-(atno-1.0)/120.); |
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227 | G4float fpdiv = std::max( 0.5, 1.0-0.25*ekin*ekin ); |
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228 | // |
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229 | // pnBlackTrackEnergy is the kinetic energy (in GeV) available for |
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230 | // proton/neutron black track particles |
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231 | // dtaBlackTrackEnergy is the kinetic energy (in GeV) available for |
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232 | // deuteron/triton/alpha black track particles |
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233 | // |
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234 | pnBlackTrackEnergy = exnu*fpdiv; |
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235 | dtaBlackTrackEnergy = exnu*(1.0-fpdiv); |
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236 | |
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237 | if( G4int(zEff+0.1) != 82 ) |
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238 | { |
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239 | G4double ran1 = -6.0; |
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240 | G4double ran2 = -6.0; |
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241 | for( G4int i=0; i<12; ++i ) |
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242 | { |
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243 | ran1 += G4UniformRand(); |
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244 | ran2 += G4UniformRand(); |
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245 | } |
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246 | pnBlackTrackEnergy *= 1.0 + ran1*gfa; |
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247 | dtaBlackTrackEnergy *= 1.0 + ran2*gfa; |
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248 | } |
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249 | pnBlackTrackEnergy = std::max( 0.0, pnBlackTrackEnergy ); |
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250 | dtaBlackTrackEnergy = std::max( 0.0, dtaBlackTrackEnergy ); |
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251 | while( pnBlackTrackEnergy+dtaBlackTrackEnergy >= ek ) |
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252 | { |
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253 | pnBlackTrackEnergy *= 1.0 - 0.5*G4UniformRand(); |
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254 | dtaBlackTrackEnergy *= 1.0 - 0.5*G4UniformRand(); |
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255 | } |
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256 | // G4cout << "EvaporationEffects "<<kineticEnergy<<" " |
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257 | // <<pnBlackTrackEnergy+dtaBlackTrackEnergy<<endl; |
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258 | return (pnBlackTrackEnergy+dtaBlackTrackEnergy)*GeV; |
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259 | } |
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260 | |
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261 | G4double G4Nucleus::AnnihilationEvaporationEffects(G4double kineticEnergy, G4double ekOrg) |
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262 | { |
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263 | // Nuclear evaporation as a function of atomic number and kinetic |
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264 | // energy (MeV) of primary particle. Modified for annihilation effects. |
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265 | // |
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266 | if( aEff < 1.5 || ekOrg < 0.) |
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267 | { |
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268 | pnBlackTrackEnergyfromAnnihilation = 0.0; |
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269 | dtaBlackTrackEnergyfromAnnihilation = 0.0; |
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270 | return 0.0; |
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271 | } |
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272 | G4double ek = kineticEnergy/GeV; |
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273 | G4float ekin = std::min( 4.0, std::max( 0.1, ek ) ); |
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274 | const G4float atno = std::min( 120., aEff ); |
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275 | const G4float gfa = 2.0*((aEff-1.0)/70.)*std::exp(-(aEff-1.0)/70.); |
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276 | |
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277 | G4float cfa = std::max( 0.15, 0.35 + ((0.35-0.05)/2.3)*std::log(ekin) ); |
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278 | G4float exnu = 7.716 * cfa * std::exp(-cfa) |
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279 | * ((atno-1.0)/120.)*std::exp(-(atno-1.0)/120.); |
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280 | G4float fpdiv = std::max( 0.5, 1.0-0.25*ekin*ekin ); |
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281 | |
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282 | pnBlackTrackEnergyfromAnnihilation = exnu*fpdiv; |
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283 | dtaBlackTrackEnergyfromAnnihilation = exnu*(1.0-fpdiv); |
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284 | |
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285 | G4double ran1 = -6.0; |
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286 | G4double ran2 = -6.0; |
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287 | for( G4int i=0; i<12; ++i ) { |
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288 | ran1 += G4UniformRand(); |
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289 | ran2 += G4UniformRand(); |
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290 | } |
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291 | pnBlackTrackEnergyfromAnnihilation *= 1.0 + ran1*gfa; |
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292 | dtaBlackTrackEnergyfromAnnihilation *= 1.0 + ran2*gfa; |
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293 | |
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294 | pnBlackTrackEnergyfromAnnihilation = std::max( 0.0, pnBlackTrackEnergyfromAnnihilation); |
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295 | dtaBlackTrackEnergyfromAnnihilation = std::max( 0.0, dtaBlackTrackEnergyfromAnnihilation); |
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296 | G4double blackSum = pnBlackTrackEnergyfromAnnihilation+dtaBlackTrackEnergyfromAnnihilation; |
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297 | if (blackSum >= ekOrg/GeV) { |
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298 | pnBlackTrackEnergyfromAnnihilation *= ekOrg/GeV/blackSum; |
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299 | dtaBlackTrackEnergyfromAnnihilation *= ekOrg/GeV/blackSum; |
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300 | } |
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301 | |
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302 | return (pnBlackTrackEnergyfromAnnihilation+dtaBlackTrackEnergyfromAnnihilation)*GeV; |
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303 | } |
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304 | |
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305 | G4double |
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306 | G4Nucleus::Cinema( G4double kineticEnergy ) |
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307 | { |
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308 | // derived from original FORTRAN code CINEMA by H. Fesefeldt (14-Oct-1987) |
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309 | // |
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310 | // input: kineticEnergy (MeV) |
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311 | // returns modified kinetic energy (MeV) |
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312 | // |
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313 | static const G4double expxu = 82.; // upper bound for arg. of exp |
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314 | static const G4double expxl = -expxu; // lower bound for arg. of exp |
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315 | |
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316 | G4double ek = kineticEnergy/GeV; |
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317 | G4double ekLog = std::log( ek ); |
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318 | G4double aLog = std::log( aEff ); |
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319 | G4double em = std::min( 1.0, 0.2390 + 0.0408*aLog*aLog ); |
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320 | G4double temp1 = -ek * std::min( 0.15, 0.0019*aLog*aLog*aLog ); |
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321 | G4double temp2 = std::exp( std::max( expxl, std::min( expxu, -(ekLog-em)*(ekLog-em)*2.0 ) ) ); |
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322 | G4double result = 0.0; |
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323 | if( std::abs( temp1 ) < 1.0 ) |
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324 | { |
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325 | if( temp2 > 1.0e-10 )result = temp1*temp2; |
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326 | } |
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327 | else result = temp1*temp2; |
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328 | if( result < -ek )result = -ek; |
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329 | return result*GeV; |
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330 | } |
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331 | |
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332 | // |
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333 | // methods for class G4Nucleus ... by Christian Volcker |
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334 | // |
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335 | |
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336 | G4ThreeVector G4Nucleus::GetFermiMomentum() |
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337 | { |
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338 | // chv: .. we assume zero temperature! |
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339 | |
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340 | // momentum is equally distributed in each phasespace volume dpx, dpy, dpz. |
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341 | G4double ranflat1= |
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342 | CLHEP::RandFlat::shoot((G4double)0.,(G4double)fermiMomentum); |
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343 | G4double ranflat2= |
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344 | CLHEP::RandFlat::shoot((G4double)0.,(G4double)fermiMomentum); |
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345 | G4double ranflat3= |
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346 | CLHEP::RandFlat::shoot((G4double)0.,(G4double)fermiMomentum); |
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347 | G4double ranmax = (ranflat1>ranflat2? ranflat1: ranflat2); |
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348 | ranmax = (ranmax>ranflat3? ranmax : ranflat3); |
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349 | |
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350 | // Isotropic momentum distribution |
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351 | G4double costheta = 2.*G4UniformRand() - 1.0; |
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352 | G4double sintheta = std::sqrt(1.0 - costheta*costheta); |
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353 | G4double phi = 2.0*pi*G4UniformRand(); |
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354 | |
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355 | G4double pz=costheta*ranmax; |
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356 | G4double px=sintheta*std::cos(phi)*ranmax; |
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357 | G4double py=sintheta*std::sin(phi)*ranmax; |
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358 | G4ThreeVector p(px,py,pz); |
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359 | return p; |
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360 | } |
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361 | |
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362 | G4ReactionProductVector* G4Nucleus::Fragmentate() |
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363 | { |
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364 | // needs implementation! |
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365 | return NULL; |
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366 | } |
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367 | |
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368 | void G4Nucleus::AddMomentum(const G4ThreeVector aMomentum) |
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369 | { |
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370 | momentum+=(aMomentum); |
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371 | } |
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372 | |
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373 | void G4Nucleus::AddExcitationEnergy( G4double anEnergy ) |
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374 | { |
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375 | excitationEnergy+=anEnergy; |
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376 | } |
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377 | |
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378 | /* end of file */ |
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379 | |
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