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15 | // * use. Please see the license in the file LICENSE and URL above * |
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18 | // * This code implementation is the result of the scientific and * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // $Id: G4StatMFMicroPartition.cc,v 1.8 2008/07/25 11:20:47 vnivanch Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-03 $ |
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29 | // |
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30 | // by V. Lara |
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31 | // -------------------------------------------------------------------- |
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32 | |
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33 | #include "G4StatMFMicroPartition.hh" |
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34 | #include "G4HadronicException.hh" |
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35 | |
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36 | |
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37 | // Copy constructor |
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38 | G4StatMFMicroPartition::G4StatMFMicroPartition(const G4StatMFMicroPartition & ) |
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39 | { |
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40 | throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroPartition::copy_constructor meant to not be accessable"); |
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41 | } |
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42 | |
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43 | // Operators |
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44 | |
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45 | G4StatMFMicroPartition & G4StatMFMicroPartition:: |
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46 | operator=(const G4StatMFMicroPartition & ) |
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47 | { |
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48 | throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroPartition::operator= meant to not be accessable"); |
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49 | return *this; |
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50 | } |
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51 | |
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52 | |
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53 | G4bool G4StatMFMicroPartition::operator==(const G4StatMFMicroPartition & ) const |
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54 | { |
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55 | //throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroPartition::operator== meant to not be accessable"); |
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56 | return false; |
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57 | } |
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58 | |
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59 | |
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60 | G4bool G4StatMFMicroPartition::operator!=(const G4StatMFMicroPartition & ) const |
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61 | { |
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62 | //throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroPartition::operator!= meant to not be accessable"); |
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63 | return true; |
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64 | } |
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65 | |
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66 | |
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67 | |
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68 | void G4StatMFMicroPartition::CoulombFreeEnergy(const G4double anA) |
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69 | { |
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70 | // This Z independent factor in the Coulomb free energy |
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71 | G4double CoulombConstFactor = 1.0/std::pow(1.0+G4StatMFParameters::GetKappaCoulomb(),1.0/3.0); |
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72 | |
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73 | CoulombConstFactor = elm_coupling * (3./5.) * |
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74 | (1. - CoulombConstFactor)/G4StatMFParameters::Getr0(); |
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75 | |
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76 | // We use the aproximation Z_f ~ Z/A * A_f |
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77 | |
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78 | if (anA == 0 || anA == 1) |
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79 | { |
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80 | _theCoulombFreeEnergy.push_back(CoulombConstFactor*(theZ/theA)*(theZ/theA)); |
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81 | } |
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82 | else if (anA == 2 || anA == 3 || anA == 4) |
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83 | { |
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84 | // Z/A ~ 1/2 |
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85 | _theCoulombFreeEnergy.push_back(CoulombConstFactor*0.5*std::pow(anA,5./3.)); |
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86 | } |
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87 | else // anA > 4 |
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88 | { |
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89 | _theCoulombFreeEnergy.push_back(CoulombConstFactor*(theZ/theA)*(theZ/theA)* |
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90 | std::pow(anA,5./3.)); |
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91 | |
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92 | } |
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93 | } |
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94 | |
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95 | |
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96 | G4double G4StatMFMicroPartition::GetCoulombEnergy(void) |
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97 | { |
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98 | G4double CoulombFactor = 1.0/ |
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99 | std::pow(1.0+G4StatMFParameters::GetKappaCoulomb(),1.0/3.0); |
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100 | |
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101 | G4double CoulombEnergy = elm_coupling*(3./5.)*theZ*theZ*CoulombFactor/ |
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102 | (G4StatMFParameters::Getr0()*std::pow(static_cast<G4double>(theA),1./3.)); |
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103 | |
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104 | for (unsigned int i = 0; i < _thePartition.size(); i++) |
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105 | CoulombEnergy += _theCoulombFreeEnergy[i] - elm_coupling*(3./5.)* |
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106 | (theZ/theA)*(theZ/theA)*std::pow(static_cast<G4double>(_thePartition[i]),5./3.)/ |
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107 | G4StatMFParameters::Getr0(); |
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108 | |
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109 | return CoulombEnergy; |
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110 | } |
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111 | |
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112 | G4double G4StatMFMicroPartition::GetPartitionEnergy(const G4double T) |
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113 | { |
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114 | G4double CoulombFactor = 1.0/ |
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115 | std::pow(1.0+G4StatMFParameters::GetKappaCoulomb(),1.0/3.0); |
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116 | |
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117 | G4double PartitionEnergy = 0.0; |
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118 | |
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119 | |
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120 | // We use the aprox that Z_f ~ Z/A * A_f |
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121 | for (unsigned int i = 0; i < _thePartition.size(); i++) |
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122 | { |
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123 | if (_thePartition[i] == 0 || _thePartition[i] == 1) |
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124 | { |
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125 | PartitionEnergy += _theCoulombFreeEnergy[i]; |
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126 | } |
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127 | else if (_thePartition[i] == 2) |
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128 | { |
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129 | PartitionEnergy += |
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130 | -2.796 // Binding Energy of deuteron ?????? |
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131 | + _theCoulombFreeEnergy[i]; |
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132 | } |
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133 | else if (_thePartition[i] == 3) |
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134 | { |
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135 | PartitionEnergy += |
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136 | -9.224 // Binding Energy of trtion/He3 ?????? |
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137 | + _theCoulombFreeEnergy[i]; |
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138 | } |
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139 | else if (_thePartition[i] == 4) |
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140 | { |
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141 | PartitionEnergy += |
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142 | -30.11 // Binding Energy of ALPHA ?????? |
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143 | + _theCoulombFreeEnergy[i] |
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144 | + 4.*T*T/InvLevelDensity(4.); |
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145 | } |
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146 | else |
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147 | { |
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148 | PartitionEnergy += |
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149 | //Volume term |
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150 | (- G4StatMFParameters::GetE0() + |
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151 | T*T/InvLevelDensity(_thePartition[i])) |
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152 | *_thePartition[i] + |
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153 | |
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154 | // Symmetry term |
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155 | G4StatMFParameters::GetGamma0()* |
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156 | (1.0-2.0*theZ/theA)*(1.0-2.0*theZ/theA)*_thePartition[i] + |
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157 | |
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158 | // Surface term |
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159 | (G4StatMFParameters::Beta(T) - T*G4StatMFParameters::DBetaDT(T))* |
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160 | std::pow(static_cast<G4double>(_thePartition[i]),2./3.) + |
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161 | |
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162 | // Coulomb term |
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163 | _theCoulombFreeEnergy[i]; |
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164 | } |
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165 | } |
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166 | |
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167 | PartitionEnergy += elm_coupling*(3./5.)*theZ*theZ*CoulombFactor/ |
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168 | (G4StatMFParameters::Getr0()*std::pow(static_cast<G4double>(theA),1./3.)) |
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169 | + (3./2.)*T*(_thePartition.size()-1); |
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170 | |
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171 | return PartitionEnergy; |
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172 | } |
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173 | |
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174 | |
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175 | G4double G4StatMFMicroPartition::CalcPartitionTemperature(const G4double U, |
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176 | const G4double FreeInternalE0) |
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177 | { |
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178 | G4double PartitionEnergy = GetPartitionEnergy(0.0); |
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179 | |
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180 | // If this happens, T = 0 MeV, which means that probability for this |
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181 | // partition will be 0 |
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182 | if (std::abs(U + FreeInternalE0 - PartitionEnergy) < 0.003) return -1.0; |
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183 | |
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184 | // Calculate temperature by midpoint method |
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185 | |
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186 | // Bracketing the solution |
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187 | G4double Ta = 0.001; |
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188 | G4double Tb = std::max(std::sqrt(8.0*U/theA),0.0012*MeV); |
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189 | G4double Tmid = 0.0; |
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190 | |
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191 | G4double Da = (U + FreeInternalE0 - GetPartitionEnergy(Ta))/U; |
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192 | G4double Db = (U + FreeInternalE0 - GetPartitionEnergy(Tb))/U; |
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193 | |
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194 | G4int maxit = 0; |
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195 | while (Da*Db > 0.0 && maxit < 1000) |
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196 | { |
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197 | ++maxit; |
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198 | Tb += 0.5*Tb; |
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199 | Db = (U + FreeInternalE0 - GetPartitionEnergy(Tb))/U; |
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200 | } |
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201 | |
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202 | G4double eps = 1.0e-14*std::abs(Ta-Tb); |
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203 | |
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204 | for (G4int i = 0; i < 1000; i++) |
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205 | { |
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206 | Tmid = (Ta+Tb)/2.0; |
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207 | if (std::abs(Ta-Tb) <= eps) return Tmid; |
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208 | G4double Dmid = (U + FreeInternalE0 - GetPartitionEnergy(Tmid))/U; |
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209 | if (std::abs(Dmid) < 0.003) return Tmid; |
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210 | if (Da*Dmid < 0.0) |
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211 | { |
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212 | Tb = Tmid; |
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213 | Db = Dmid; |
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214 | } |
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215 | else |
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216 | { |
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217 | Ta = Tmid; |
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218 | Da = Dmid; |
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219 | } |
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220 | } |
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221 | // if we arrive here the temperature could not be calculated |
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222 | G4cerr << "G4StatMFMicroPartition::CalcPartitionTemperature: I can't calculate the temperature" |
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223 | << G4endl; |
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224 | // and set probability to 0 returning T < 0 |
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225 | return -1.0; |
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226 | |
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227 | } |
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228 | |
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229 | |
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230 | G4double G4StatMFMicroPartition::CalcPartitionProbability(const G4double U, |
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231 | const G4double FreeInternalE0, |
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232 | const G4double SCompound) |
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233 | { |
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234 | G4double T = CalcPartitionTemperature(U,FreeInternalE0); |
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235 | if ( T <= 0.0) return _Probability = 0.0; |
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236 | _Temperature = T; |
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237 | |
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238 | |
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239 | // Factorial of fragment multiplicity |
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240 | G4double Fact = 1.0; |
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241 | unsigned int i; |
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242 | for (i = 0; i < _thePartition.size() - 1; i++) |
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243 | { |
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244 | G4double f = 1.0; |
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245 | for (unsigned int ii = i+1; i< _thePartition.size(); i++) |
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246 | { |
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247 | if (_thePartition[i] == _thePartition[ii]) f++; |
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248 | } |
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249 | Fact *= f; |
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250 | } |
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251 | |
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252 | G4double ProbDegeneracy = 1.0; |
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253 | G4double ProbA32 = 1.0; |
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254 | |
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255 | for (i = 0; i < _thePartition.size(); i++) |
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256 | { |
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257 | ProbDegeneracy *= GetDegeneracyFactor(static_cast<G4int>(_thePartition[i])); |
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258 | ProbA32 *= static_cast<G4double>(_thePartition[i])* |
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259 | std::sqrt(static_cast<G4double>(_thePartition[i])); |
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260 | } |
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261 | |
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262 | // Compute entropy |
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263 | G4double PartitionEntropy = 0.0; |
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264 | for (i = 0; i < _thePartition.size(); i++) |
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265 | { |
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266 | // interaction entropy for alpha |
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267 | if (_thePartition[i] == 4) |
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268 | { |
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269 | PartitionEntropy += |
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270 | 2.0*T*_thePartition[i]/InvLevelDensity(_thePartition[i]); |
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271 | } |
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272 | // interaction entropy for Af > 4 |
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273 | else if (_thePartition[i] > 4) |
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274 | { |
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275 | PartitionEntropy += |
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276 | 2.0*T*_thePartition[i]/InvLevelDensity(_thePartition[i]) |
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277 | - G4StatMFParameters::DBetaDT(T) |
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278 | * std::pow(static_cast<G4double>(_thePartition[i]),2.0/3.0); |
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279 | } |
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280 | } |
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281 | |
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282 | // Thermal Wave Lenght = std::sqrt(2 pi hbar^2 / nucleon_mass T) |
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283 | G4double ThermalWaveLenght3 = 16.15*fermi/std::sqrt(T); |
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284 | ThermalWaveLenght3 = ThermalWaveLenght3*ThermalWaveLenght3*ThermalWaveLenght3; |
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285 | |
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286 | // Translational Entropy |
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287 | G4double kappa = (1. + elm_coupling*(std::pow(static_cast<G4double>(_thePartition.size()),1./3.)-1.0) |
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288 | /(G4StatMFParameters::Getr0()*std::pow(static_cast<G4double>(theA),1./3.))); |
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289 | kappa = kappa*kappa*kappa; |
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290 | kappa -= 1.; |
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291 | G4double V0 = (4./3.)*pi*theA*G4StatMFParameters::Getr0()*G4StatMFParameters::Getr0()* |
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292 | G4StatMFParameters::Getr0(); |
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293 | G4double FreeVolume = kappa*V0; |
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294 | G4double TranslationalS = std::max(0.0, std::log(ProbA32/Fact) + |
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295 | (_thePartition.size()-1.0)*std::log(FreeVolume/ThermalWaveLenght3) + |
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296 | 1.5*(_thePartition.size()-1.0) - (3./2.)*std::log(theA)); |
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297 | |
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298 | PartitionEntropy += std::log(ProbDegeneracy) + TranslationalS; |
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299 | _Entropy = PartitionEntropy; |
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300 | |
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301 | // And finally compute probability of fragment configuration |
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302 | G4double exponent = PartitionEntropy-SCompound; |
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303 | if (exponent > 700.0) exponent = 700.0; |
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304 | return _Probability = std::exp(exponent); |
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305 | } |
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306 | |
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307 | |
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308 | |
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309 | G4double G4StatMFMicroPartition::GetDegeneracyFactor(const G4int A) |
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310 | { |
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311 | // Degeneracy factors are statistical factors |
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312 | // DegeneracyFactor for nucleon is (2S_n + 1)(2I_n + 1) = 4 |
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313 | G4double DegFactor = 0; |
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314 | if (A > 4) DegFactor = 1.0; |
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315 | else if (A == 1) DegFactor = 4.0; // nucleon |
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316 | else if (A == 2) DegFactor = 3.0; // Deuteron |
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317 | else if (A == 3) DegFactor = 2.0+2.0; // Triton + He3 |
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318 | else if (A == 4) DegFactor = 1.0; // alpha |
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319 | return DegFactor; |
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320 | } |
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321 | |
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322 | |
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323 | G4StatMFChannel * G4StatMFMicroPartition::ChooseZ(const G4double A0, const G4double Z0, const G4double MeanT) |
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324 | // Gives fragments charges |
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325 | { |
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326 | std::vector<G4int> FragmentsZ; |
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327 | |
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328 | G4int ZBalance = 0; |
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329 | do |
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330 | { |
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331 | G4double CC = G4StatMFParameters::GetGamma0()*8.0; |
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332 | G4int SumZ = 0; |
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333 | for (unsigned int i = 0; i < _thePartition.size(); i++) |
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334 | { |
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335 | G4double ZMean; |
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336 | G4double Af = _thePartition[i]; |
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337 | if (Af > 1.5 && Af < 4.5) ZMean = 0.5*Af; |
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338 | else ZMean = Af*Z0/A0; |
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339 | G4double ZDispersion = std::sqrt(Af * MeanT/CC); |
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340 | G4int Zf; |
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341 | do |
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342 | { |
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343 | Zf = static_cast<G4int>(G4RandGauss::shoot(ZMean,ZDispersion)); |
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344 | } |
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345 | while (Zf < 0 || Zf > Af); |
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346 | FragmentsZ.push_back(Zf); |
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347 | SumZ += Zf; |
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348 | } |
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349 | ZBalance = static_cast<G4int>(Z0) - SumZ; |
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350 | } |
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351 | while (std::abs(ZBalance) > 1.1); |
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352 | FragmentsZ[0] += ZBalance; |
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353 | |
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354 | G4StatMFChannel * theChannel = new G4StatMFChannel; |
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355 | for (unsigned int i = 0; i < _thePartition.size(); i++) |
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356 | { |
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357 | theChannel->CreateFragment(_thePartition[i],FragmentsZ[i]); |
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358 | } |
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359 | |
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360 | return theChannel; |
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361 | } |
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