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 | // Implementation of the HETC88 code into Geant4. |
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28 | // Evaporation and De-excitation parts |
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29 | // T. Lampen, Helsinki Institute of Physics, May-2000 |
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30 | |
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31 | #include "G4BEChargedChannel.hh" |
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32 | |
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33 | |
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34 | G4BEChargedChannel::G4BEChargedChannel() |
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35 | { |
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36 | verboseLevel = 0; |
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37 | } |
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38 | |
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39 | |
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40 | G4BEChargedChannel::~G4BEChargedChannel() |
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41 | { |
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42 | } |
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43 | |
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44 | |
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45 | void G4BEChargedChannel::calculateProbability() |
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46 | { |
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47 | G4int residualZ = nucleusZ - particleZ; |
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48 | G4int residualA = nucleusA - particleA; |
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49 | |
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50 | // Check if nucleus is too small, if this evaporation channel |
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51 | // leads to an impossible residual nucleus or if there is no enough |
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52 | // energy. |
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53 | if ( nucleusA < 2.0 * particleA || |
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54 | nucleusZ < 2.0 * particleZ || |
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55 | residualA <= residualZ || |
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56 | excitationEnergy - getThresh() - correction < 0 ) |
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57 | { |
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58 | if ( verboseLevel >= 6 ) |
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59 | G4cout << "G4BEChargedChannel : calculateProbability for " << getName() << " = 0 " << G4endl; |
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60 | emissionProbability = 0; |
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61 | return; |
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62 | } |
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63 | |
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64 | // In HETC88 s-s0 was used in std::exp( s ), in which s0 was either 50 or |
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65 | // max(s_i), where i goes over all channels. |
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66 | |
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67 | G4double levelParam = getLevelDensityParameter(); |
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68 | G4double s = 2 * std::sqrt( levelParam * ( excitationEnergy - getThresh() - correction ) ); |
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69 | G4double constant = A / 2 * ( 2 * spin + 1 ) * ( 1 + coulombFactor() ); |
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70 | G4double eye1 = ( std::pow( s, 2. ) - 3 * s + 3 ) / ( 4 * std::pow( levelParam, 2. ) ) * std::exp( s ); |
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71 | |
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72 | emissionProbability = constant * std::pow( G4double(residualA), 0.6666666 ) * eye1; |
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73 | |
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74 | if ( verboseLevel >= 6 ) |
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75 | G4cout << "G4BEChargedChannel : calculateProbability for " << getName() << G4endl |
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76 | << " res A = " << residualA << G4endl |
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77 | << " res Z = " << residualZ << G4endl |
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78 | << " c*(c_i+1) = "<< constant << G4endl |
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79 | << " qmfactor = "<< qmFactor() << G4endl |
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80 | << " coulombfactor = "<< coulombFactor() << G4endl |
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81 | << " E = " << excitationEnergy << G4endl |
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82 | << " correction = " << correction << G4endl |
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83 | << " eye1 = " << eye1 << G4endl |
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84 | << " levelParam = " << levelParam << G4endl |
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85 | << " thresh = " << getThresh() << G4endl |
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86 | << " s = " << s << G4endl |
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87 | << " probability = " << emissionProbability << G4endl; |
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88 | |
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89 | return; |
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90 | } |
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91 | |
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92 | |
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93 | G4double G4BEChargedChannel::sampleKineticEnergy() |
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94 | { |
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95 | // G4double randExp1; |
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96 | // G4double randExp2; |
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97 | // G4double s; |
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98 | // G4double levelParam; |
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99 | // G4double kineticEnergyAv; |
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100 | // G4double kineticEnergy; |
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101 | |
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102 | // randExp1 = RandExponential::shoot( 1 ); |
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103 | // randExp2 = RandExponential::shoot( 1 ); |
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104 | // levelParam = getLevelDensityParameter(); |
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105 | // s = 2 * std::sqrt( levelParam * ( excitationEnergy - getThresh() - correction ) ); |
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106 | // kineticEnergyAv = 2 * ( std::pow( s, 3. ) - 6.0 * std::pow( s, 2. ) + 15.0 * s - 15.0 ) / |
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107 | // ( ( 2.0 * std::pow( s, 2. ) - 6.0 * s + 6.0 ) * levelParam ); |
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108 | |
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109 | // kineticEnergy = 0.5 * ( randExp1 + randExp2 ) * kineticEnergyAv + getThresh() - getQ(); |
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110 | |
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111 | // if ( verboseLevel >= 10 ) |
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112 | // G4cout << " G4BEChargedChannel : sampleKineticEnergy() " << G4endl |
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113 | // << " kinetic e = " << kineticEnergy << G4endl |
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114 | // << " average = " << kineticEnergyAv << G4endl |
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115 | // << " s = " << s << G4endl |
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116 | // << " levelParam = " << levelParam << G4endl |
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117 | // << " randExp1 = " << randExp1 << G4endl |
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118 | // << " randExp2 = " << randExp2 << G4endl; |
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119 | |
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120 | G4double levelParam; |
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121 | levelParam = getLevelDensityParameter(); |
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122 | |
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123 | const G4double xMax = excitationEnergy - getThresh() - correction; // maximum number |
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124 | const G4double xProb = ( - 1 + std::sqrt ( 1 + 4 * levelParam * xMax ) ) / ( 2 * levelParam ); // most probable value |
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125 | const G4double m = xProb * std::exp ( 2 * std::sqrt ( levelParam * ( xMax - xProb ) ) ); // maximum value of P(x) |
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126 | |
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127 | // Sample x according to density function P(x) with rejection method |
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128 | G4double r1; |
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129 | G4double r2; |
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130 | G4int koe=0; |
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131 | do |
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132 | { |
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133 | r1 = G4UniformRand() * xMax; |
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134 | r2 = G4UniformRand() * m; |
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135 | koe++; |
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136 | } |
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137 | while ( r1 * std::exp ( 2 * std::sqrt ( levelParam * ( xMax - r1 ) ) ) < r2 ); |
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138 | |
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139 | // G4cout << "Q ch " << koe << G4endl; |
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140 | G4double kineticEnergy = r1 + getCoulomb(); // add coulomb potential; |
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141 | |
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142 | if ( verboseLevel >= 10 ) |
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143 | G4cout << " G4BENeutronChannel : sampleKineticEnergy() " << G4endl |
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144 | << " kinetic n e = " << kineticEnergy << G4endl |
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145 | << " levelParam = " << levelParam << G4endl |
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146 | << " thresh= " << getThresh() << G4endl; |
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147 | |
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148 | return kineticEnergy; |
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149 | } |
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150 | |
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151 | |
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152 | G4double G4BEChargedChannel::coulombFactorForProton() |
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153 | { |
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154 | // Coefficient c_p:s for empirical cross section formula are |
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155 | // defined with the proton constant. See Dostrovsky, Phys. Rev., |
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156 | // vol. 116, 1959. |
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157 | G4double t[7] = { 0.08 , 0 , -0.06 , -0.1 , -0.1 , -0.1 , -0.1 }; |
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158 | G4int Z = nucleusZ - particleZ; |
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159 | |
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160 | if ( Z >= 70.0 ) return t[6]; |
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161 | if ( Z <= 10.0 ) return t[0]; |
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162 | |
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163 | // Linear interpolation |
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164 | G4int n = G4int( 0.1 * Z + 1.0 ); |
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165 | G4float x = ( 10 * n - Z ) * 0.1; |
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166 | G4double ret_val = x * t[n - 2] + ( 1.0 - x ) * t[n-1]; |
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167 | |
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168 | return ret_val; |
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169 | } |
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170 | |
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171 | |
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172 | G4double G4BEChargedChannel::qmFactorForProton() |
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173 | { |
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174 | // Coefficient k_p for empirical cross section formula are defined |
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175 | // with the proton constant. See Dostrovsky, Phys. Rev., vol. 116, |
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176 | // 1959 |
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177 | G4double t[7] = { 0.36, 0.51, 0.60, 0.66, 0.68, 0.69, 0.69 }; |
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178 | G4int Z = nucleusZ - particleZ; |
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179 | |
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180 | if ( Z >= 70.0 ) return t[6]; |
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181 | if ( Z <= 10.0 ) return t[0]; |
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182 | |
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183 | // Linear interpolation |
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184 | G4int n = G4int( 0.1 * Z + 1.0 ); |
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185 | G4float x = ( 10 * n - Z ) * 0.1; |
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186 | return x * t[n - 2] + ( 1.0 - x ) * t[n-1]; |
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187 | } |
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188 | |
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189 | |
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190 | G4double G4BEChargedChannel::qmFactorForAlpha() |
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191 | { |
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192 | // Coefficient k_alpha for empirical cross section formula presented |
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193 | // in Dostrovsky, Phys. Rev., vol. 116, 1959 |
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194 | |
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195 | G4double t[7] = { 0.77, 0.81, 0.85, 0.89, 0.93, 0.97, 1.00 }; |
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196 | G4int Z = nucleusZ - particleZ; |
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197 | |
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198 | if ( Z >= 70.0 ) return t[6]; |
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199 | if ( Z <= 10.0 ) return t[0]; |
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200 | |
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201 | // Linear interpolation |
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202 | G4int n = G4int( 0.1 * Z + 1.0 ); |
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203 | G4float x = ( 10 * n - Z ) * 0.1; |
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204 | return x * t[n - 2] + ( 1.0 - x ) * t[n-1]; |
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205 | } |
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