1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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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 | // |
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29 | // GEANT4 Class file |
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30 | // |
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31 | // |
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32 | // File name: G4ModifiedTsai |
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33 | // |
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34 | // Author: Andreia Trindade (andreia@lip.pt) |
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35 | // Pedro Rodrigues (psilva@lip.pt) |
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36 | // Luis Peralta (luis@lip.pt) |
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37 | // |
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38 | // Creation date: 21 March 2003 |
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39 | // |
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40 | // Modifications: |
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41 | // 21 Mar 2003 A. Trindade First implementation acording with new design |
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42 | // 24 Mar 2003 & Fix in Tsai generator in order to prevent theta generation above pi |
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43 | // |
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44 | // Class Description: |
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45 | // |
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46 | // Concrete base class for Bremsstrahlung Angular Distribution Generation - Tsai Model |
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47 | // |
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48 | // Class Description: End |
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49 | // |
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50 | // ------------------------------------------------------------------- |
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51 | // |
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52 | // |
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53 | |
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54 | #include "G4ModifiedTsai.hh" |
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55 | #include "Randomize.hh" |
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56 | // |
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57 | |
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58 | G4ModifiedTsai::G4ModifiedTsai(const G4String& name):G4VBremAngularDistribution(name) |
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59 | {;} |
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60 | |
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61 | // |
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62 | |
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63 | G4ModifiedTsai::~G4ModifiedTsai() |
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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 | G4double G4ModifiedTsai::PolarAngle(const G4double initial_energy, |
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69 | const G4double, // final_energy |
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70 | const G4int ) // Z |
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71 | { |
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72 | |
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73 | // Sample gamma angle (Z - axis along the parent particle). |
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74 | // Universal distribution suggested by L. Urban (Geant3 manual (1993) |
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75 | // Phys211) derived from Tsai distribution (Rev Mod Phys 49,421(1977)) |
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76 | |
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77 | G4double totalEnergy = initial_energy + electron_mass_c2; |
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78 | |
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79 | const G4double a1 = 0.625, a2 = 3.*a1, d = 27.; |
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80 | G4double u, theta = 0; |
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81 | |
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82 | do{ |
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83 | u = - std::log(G4UniformRand()*G4UniformRand()); |
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84 | |
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85 | if (9./(9.+d) > G4UniformRand()) u /= a1; |
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86 | else u /= a2; |
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87 | |
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88 | theta = u*electron_mass_c2/totalEnergy; |
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89 | }while(u > (totalEnergy*pi/electron_mass_c2)); |
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90 | |
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91 | return theta; |
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92 | } |
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93 | // |
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94 | |
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95 | void G4ModifiedTsai::PrintGeneratorInformation() const |
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96 | { |
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97 | |
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98 | G4cout << "\n" << G4endl; |
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99 | G4cout << "Bremsstrahlung Angular Generator is Modified Tsai" << G4endl; |
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100 | G4cout << "Universal distribution suggested by L. Urban (Geant3 manual (1993) Phys211)" << G4endl; |
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101 | G4cout << "Derived from Tsai distribution (Rev Mod Phys 49,421(1977)) \n" << G4endl; |
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102 | } |
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