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 | //J.M. Quesada (August2008). Based on: |
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27 | // |
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28 | // Hadronic Process: Nuclear De-excitations |
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29 | // by V. Lara (Oct 1998) |
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30 | // |
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31 | // Modif (03 September 2008) by J. M. Quesada for external choice of inverse |
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32 | // cross section option |
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33 | |
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34 | #include "G4NeutronEvaporationProbability.hh" |
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35 | |
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36 | G4NeutronEvaporationProbability::G4NeutronEvaporationProbability() : |
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37 | G4EvaporationProbability(1,0,2,&theCoulombBarrier) // A,Z,Gamma,&theCoulombBarrier |
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38 | { |
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39 | |
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40 | } |
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41 | |
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42 | |
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43 | G4NeutronEvaporationProbability::G4NeutronEvaporationProbability(const G4NeutronEvaporationProbability &) : G4EvaporationProbability() |
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44 | { |
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45 | throw G4HadronicException(__FILE__, __LINE__, "G4NeutronEvaporationProbability::copy_constructor meant to not be accessable"); |
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46 | } |
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47 | |
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48 | |
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49 | |
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50 | |
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51 | const G4NeutronEvaporationProbability & G4NeutronEvaporationProbability:: |
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52 | operator=(const G4NeutronEvaporationProbability &) |
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53 | { |
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54 | throw G4HadronicException(__FILE__, __LINE__, "G4NeutronEvaporationProbability::operator= meant to not be accessable"); |
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55 | return *this; |
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56 | } |
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57 | |
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58 | |
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59 | G4bool G4NeutronEvaporationProbability::operator==(const G4NeutronEvaporationProbability &) const |
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60 | { |
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61 | return false; |
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62 | } |
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63 | |
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64 | G4bool G4NeutronEvaporationProbability::operator!=(const G4NeutronEvaporationProbability &) const |
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65 | { |
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66 | return true; |
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67 | } |
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68 | |
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69 | G4double G4NeutronEvaporationProbability::CalcAlphaParam(const G4Fragment & fragment) |
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70 | { return 0.76+2.2/std::pow(static_cast<G4double>(fragment.GetA()-GetA()),1.0/3.0);} |
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71 | |
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72 | |
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73 | G4double G4NeutronEvaporationProbability::CalcBetaParam(const G4Fragment & fragment) |
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74 | { return (2.12/std::pow(static_cast<G4double>(fragment.GetA()-GetA()),2.0/3.0) - 0.05)*MeV/ |
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75 | CalcAlphaParam(fragment); } |
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76 | |
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77 | |
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78 | //////////////////////////////////////////////////////////////////////////////////// |
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79 | //J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections |
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80 | //OPT=0 Dostrovski's parameterization |
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81 | //OPT=1,2 Chatterjee's paramaterization |
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82 | //OPT=3,4 Kalbach's parameterization |
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83 | // |
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84 | G4double G4NeutronEvaporationProbability::CrossSection(const G4Fragment & fragment, const G4double K) |
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85 | { |
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86 | theA=GetA(); |
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87 | theZ=GetZ(); |
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88 | ResidualA=fragment.GetA()-theA; |
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89 | ResidualZ=fragment.GetZ()-theZ; |
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90 | |
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91 | ResidualAthrd=std::pow(ResidualA,0.33333); |
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92 | FragmentA=fragment.GetA(); |
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93 | FragmentAthrd=std::pow(FragmentA,0.33333); |
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94 | |
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95 | |
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96 | if (OPTxs==0) {std::ostringstream errOs; |
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97 | errOs << "We should'n be here (OPT =0) at evaporation cross section calculation (neutrons)!!" <<G4endl; |
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98 | throw G4HadronicException(__FILE__, __LINE__, errOs.str()); |
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99 | return 0.;} |
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100 | else if( OPTxs==1 ||OPTxs==2) return GetOpt12( K); |
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101 | else if (OPTxs==3 || OPTxs==4) return GetOpt34( K); |
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102 | else{ |
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103 | std::ostringstream errOs; |
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104 | errOs << "BAD NEUTRON CROSS SECTION OPTION AT EVAPORATION!!" <<G4endl; |
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105 | throw G4HadronicException(__FILE__, __LINE__, errOs.str()); |
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106 | return 0.; |
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107 | } |
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108 | } |
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109 | |
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110 | |
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111 | |
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112 | |
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113 | |
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114 | |
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115 | //********************* OPT=1,2 : Chatterjee's cross section ************************ |
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116 | //(fitting to cross section from Bechetti & Greenles OM potential) |
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117 | |
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118 | G4double G4NeutronEvaporationProbability::GetOpt12(const G4double K) |
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119 | { |
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120 | |
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121 | G4double Kc=K; |
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122 | |
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123 | // JMQ xsec is set constat above limit of validity |
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124 | if (K>50) Kc=50; |
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125 | |
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126 | G4double landa, landa0, landa1, mu, mu0, mu1,nu, nu0, nu1, nu2,xs; |
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127 | |
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128 | landa0 = 18.57; |
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129 | landa1 = -22.93; |
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130 | mu0 = 381.7; |
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131 | mu1 = 24.31; |
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132 | nu0 = 0.172; |
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133 | nu1 = -15.39; |
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134 | nu2 = 804.8; |
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135 | landa = landa0/ResidualAthrd + landa1; |
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136 | mu = mu0*ResidualAthrd + mu1*ResidualAthrd*ResidualAthrd; |
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137 | nu = nu0*ResidualAthrd*ResidualA + nu1*ResidualAthrd*ResidualAthrd + nu2 ; |
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138 | xs=landa*Kc + mu + nu/Kc; |
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139 | if (xs <= 0.0 ){ |
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140 | std::ostringstream errOs; |
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141 | G4cout<<"WARNING: NEGATIVE OPT=1 neutron cross section "<<G4endl; |
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142 | errOs << "RESIDUAL: Ar=" << ResidualA << " Zr=" << ResidualZ <<G4endl; |
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143 | errOs <<" xsec("<<Kc<<" MeV) ="<<xs <<G4endl; |
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144 | throw G4HadronicException(__FILE__, __LINE__, errOs.str()); |
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145 | } |
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146 | return xs; |
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147 | } |
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148 | |
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149 | |
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150 | // *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)************* |
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151 | G4double G4NeutronEvaporationProbability::GetOpt34(const G4double K) |
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152 | { |
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153 | |
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154 | G4double landa, landa0, landa1, mu, mu0, mu1,nu, nu0, nu1, nu2; |
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155 | G4double p, p0, p1, p2; |
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156 | G4double flow,spill,ec,ecsq,xnulam,etest(0.),ra(0.),a,signor(1.),sig; |
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157 | G4double b,ecut,cut,ecut2,geom,elab; |
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158 | |
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159 | //safety initialization |
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160 | landa0=0; |
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161 | landa1=0; |
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162 | mu0=0.; |
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163 | mu1=0.; |
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164 | nu0=0.; |
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165 | nu1=0.; |
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166 | nu2=0.; |
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167 | p0=0.; |
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168 | p1=0.; |
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169 | p2=0.; |
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170 | |
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171 | |
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172 | flow = 1.e-18; |
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173 | spill= 1.0e+18; |
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174 | |
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175 | |
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176 | |
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177 | // PRECO xs for neutrons is choosen |
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178 | |
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179 | p0 = -312.; |
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180 | p1= 0.; |
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181 | p2 = 0.; |
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182 | landa0 = 12.10; |
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183 | landa1= -11.27; |
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184 | mu0 = 234.1; |
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185 | mu1 = 38.26; |
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186 | nu0 = 1.55; |
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187 | nu1 = -106.1; |
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188 | nu2 = 1280.8; |
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189 | |
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190 | if (ResidualA < 40.) signor=0.7+ResidualA*0.0075; |
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191 | if (ResidualA > 210.) signor = 1. + (ResidualA-210.)/250.; |
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192 | landa = landa0/ResidualAthrd + landa1; |
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193 | mu = mu0*ResidualAthrd + mu1*ResidualAthrd*ResidualAthrd; |
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194 | nu = nu0*ResidualAthrd*ResidualA + nu1*ResidualAthrd*ResidualAthrd + nu2; |
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195 | |
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196 | // JMQ very low energy behaviour corrected (problem for A (apprx.)>60) |
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197 | if (nu < 0.)nu=-nu; |
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198 | |
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199 | ec = 0.5; |
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200 | ecsq = 0.25; |
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201 | p = p0; |
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202 | xnulam = 1.; |
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203 | etest = 32.; |
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204 | // ** etest is the energy above which the rxn cross section is |
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205 | // ** compared with the geometrical limit and the max taken. |
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206 | // ** xnulam here is a dummy value to be used later. |
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207 | |
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208 | |
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209 | |
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210 | a = -2.*p*ec + landa - nu/ecsq; |
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211 | b = p*ecsq + mu + 2.*nu/ec; |
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212 | ecut = 0.; |
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213 | cut = a*a - 4.*p*b; |
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214 | if (cut > 0.) ecut = std::sqrt(cut); |
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215 | ecut = (ecut-a) / (p+p); |
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216 | ecut2 = ecut; |
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217 | if (cut < 0.) ecut2 = ecut - 2.; |
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218 | elab = K * FragmentA / ResidualA; |
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219 | sig = 0.; |
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220 | if (elab <= ec) { //start for E<Ec |
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221 | if (elab > ecut2) sig = (p*elab*elab+a*elab+b) * signor; |
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222 | } //end for E<Ec |
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223 | else { //start for E>Ec |
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224 | sig = (landa*elab+mu+nu/elab) * signor; |
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225 | geom = 0.; |
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226 | if (xnulam < flow || elab < etest) return sig; |
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227 | geom = std::sqrt(theA*K); |
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228 | geom = 1.23*ResidualAthrd + ra + 4.573/geom; |
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229 | geom = 31.416 * geom * geom; |
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230 | sig = std::max(geom,sig); |
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231 | } |
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232 | return sig;} |
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233 | |
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234 | // ************************** end of cross sections ******************************* |
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235 | |
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