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 | // $Id: G4Generator2BS.cc,v 1.10 2010/10/14 14:01:02 vnivanch Exp $ |
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27 | // GEANT4 tag $Name: geant4-09-04-ref-00 $ |
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28 | // |
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29 | // ------------------------------------------------------------------- |
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30 | // |
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31 | // GEANT4 Class file |
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32 | // |
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33 | // |
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34 | // File name: G4Generator2BS |
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35 | // |
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36 | // Author: Andreia Trindade (andreia@lip.pt) |
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37 | // Pedro Rodrigues (psilva@lip.pt) |
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38 | // Luis Peralta (luis@lip.pt) |
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39 | // |
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40 | // Creation date: 2 June 2003 |
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41 | // |
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42 | // Modifications: |
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43 | // 02 Jun 2003 First implementation acording with new design |
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44 | // 05 Nov 2003 MGP Fixed std namespace |
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45 | // 17 Nov 2003 MGP Fixed compilation problem on Windows |
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46 | // 12 Oct 2010 V.Ivanchenko Moved RejectionFunction inline, use G4Pow to speadup |
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47 | // |
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48 | // Class Description: |
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49 | // |
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50 | // Concrete base class for Bremsstrahlung Angular Distribution Generation |
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51 | // 2BS Distribution |
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52 | // |
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53 | // Class Description: End |
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54 | // |
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55 | // ------------------------------------------------------------------- |
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56 | // |
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57 | |
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58 | #include "G4Generator2BS.hh" |
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59 | #include "Randomize.hh" |
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60 | #include "G4Pow.hh" |
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61 | |
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62 | // |
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63 | |
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64 | G4Generator2BS::G4Generator2BS(const G4String&) |
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65 | : G4VBremAngularDistribution("AngularGen2BS") |
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66 | { |
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67 | g4pow = G4Pow::GetInstance(); |
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68 | } |
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69 | |
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70 | // |
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71 | |
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72 | G4Generator2BS::~G4Generator2BS() |
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73 | {} |
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74 | |
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75 | // |
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76 | |
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77 | G4double G4Generator2BS::PolarAngle(const G4double initial_energy, |
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78 | const G4double final_energy, |
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79 | const G4int Z) |
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80 | { |
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81 | |
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82 | // Adapted from "Improved bremsstrahlung photon angular sampling in the EGS4 code system" |
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83 | // by Alex F. Bielajew, Rahde Mohan anc Chen-Shou Chui, PIRS-0203 |
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84 | // Ionizing Radiation Standards |
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85 | // Institute for National Measurement Standards |
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86 | // National Research Council of Canada |
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87 | // Departement of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York |
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88 | |
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89 | G4double theta = 0; |
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90 | |
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91 | G4double initialTotalEnergy = (initial_energy+electron_mass_c2)/electron_mass_c2; |
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92 | G4double finalTotalEnergy = (final_energy+electron_mass_c2)/electron_mass_c2; |
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93 | EnergyRatio = finalTotalEnergy/initialTotalEnergy; |
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94 | G4double gMaxEnergy = (pi*initialTotalEnergy)*(pi*initialTotalEnergy); |
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95 | |
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96 | //G4double Zeff = std::sqrt(static_cast<G4double>(Z) * (static_cast<G4double>(Z) + 1.0)); |
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97 | //z = (0.00008116224*(std::pow(Zeff,0.3333333))); |
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98 | |
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99 | // VI speadup |
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100 | z = 0.00008116224*(g4pow->Z13(Z) + g4pow->Z13(Z+1)); |
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101 | |
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102 | // Rejection arguments |
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103 | rejection_argument1 = (1.0+EnergyRatio*EnergyRatio); |
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104 | rejection_argument2 = - 2.0*EnergyRatio + 3.0*rejection_argument1; |
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105 | rejection_argument3 = ((1-EnergyRatio)/(2.0*initialTotalEnergy*EnergyRatio))* |
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106 | ((1-EnergyRatio)/(2.0*initialTotalEnergy*EnergyRatio)); |
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107 | |
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108 | // Calculate rejection function at 0, 1 and Emax |
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109 | G4double gfunction0 = RejectionFunction(0.0); |
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110 | G4double gfunction1 = RejectionFunction(1.0); |
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111 | G4double gfunctionEmax = RejectionFunction(gMaxEnergy); |
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112 | |
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113 | // Calculate Maximum value |
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114 | G4double gMaximum = std::max(gfunction0,gfunction1); |
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115 | gMaximum = std::max(gMaximum,gfunctionEmax); |
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116 | |
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117 | G4double rand, gfunctionTest, randTest; |
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118 | |
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119 | do{ |
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120 | rand = G4UniformRand(); |
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121 | rand /= (1 - rand + 1.0/gMaxEnergy); |
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122 | gfunctionTest = RejectionFunction(rand); |
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123 | randTest = G4UniformRand(); |
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124 | |
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125 | } while(randTest*gMaximum > gfunctionTest); |
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126 | |
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127 | theta = std::sqrt(rand)/initialTotalEnergy; |
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128 | |
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129 | return theta; |
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130 | } |
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131 | |
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132 | // |
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133 | |
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134 | void G4Generator2BS::PrintGeneratorInformation() const |
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135 | { |
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136 | G4cout << "\n" << G4endl; |
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137 | G4cout << "Bremsstrahlung Angular Generator is 2BS Generator " |
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138 | << "from 2BS Koch & Motz distribution (Rev Mod Phys 31(4), 920 (1959))" << G4endl; |
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139 | G4cout << "Sampling algorithm adapted from PIRS-0203" << G4endl; |
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140 | G4cout << "\n" << G4endl; |
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141 | } |
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142 | |
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