1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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9 | // * include a list of copyright holders. * |
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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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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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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: G4eeToPGammaModel.cc,v 1.2 2009/02/20 16:38:33 vnivanch Exp $ |
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27 | // GEANT4 tag $Name: geant4-09-03 $ |
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28 | // |
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29 | // ------------------------------------------------------------------- |
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30 | // |
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31 | // GEANT4 Class header file |
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32 | // |
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33 | // |
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34 | // File name: G4eeToPGammaModel |
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35 | // |
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36 | // Author: Vladimir Ivanchenko |
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37 | // |
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38 | // Creation date: 25.10.2003 |
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39 | // |
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40 | // Modifications: |
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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 | |
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46 | |
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47 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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48 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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49 | |
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50 | #include "G4eeToPGammaModel.hh" |
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51 | #include "Randomize.hh" |
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52 | #include "G4PionZero.hh" |
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53 | #include "G4Eta.hh" |
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54 | #include "G4Gamma.hh" |
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55 | #include "G4DynamicParticle.hh" |
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56 | #include "G4PhysicsVector.hh" |
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57 | #include "G4PhysicsLinearVector.hh" |
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58 | #include "G4eeCrossSections.hh" |
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59 | |
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60 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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61 | |
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62 | using namespace std; |
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63 | |
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64 | G4eeToPGammaModel::G4eeToPGammaModel(G4eeCrossSections* cr, const G4String& npart): |
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65 | cross(cr) |
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66 | { |
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67 | pi0 = G4PionZero::PionZero(); |
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68 | if(npart == "pi0") { |
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69 | massR = 782.62*MeV; |
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70 | particle = pi0; |
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71 | } else { |
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72 | massR = 1019.46*MeV; |
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73 | particle = G4Eta::Eta(); |
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74 | } |
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75 | massP = particle->GetPDGMass(); |
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76 | } |
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77 | |
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78 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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79 | |
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80 | G4eeToPGammaModel::~G4eeToPGammaModel() |
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81 | {} |
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82 | |
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83 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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84 | |
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85 | G4double G4eeToPGammaModel::ThresholdEnergy() const |
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86 | { |
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87 | return LowEnergy(); |
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88 | } |
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89 | |
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90 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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91 | |
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92 | G4double G4eeToPGammaModel::PeakEnergy() const |
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93 | { |
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94 | return massR; |
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95 | } |
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96 | |
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97 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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98 | |
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99 | G4double G4eeToPGammaModel::ComputeCrossSection(G4double e) const |
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100 | { |
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101 | G4double ee = std::min(HighEnergy(),e); |
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102 | G4double xs; |
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103 | if(particle == pi0) xs = cross->CrossSectionPi0G(ee); |
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104 | else xs = cross->CrossSectionEtaG(ee); |
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105 | return xs; |
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106 | } |
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107 | |
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108 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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109 | |
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110 | G4PhysicsVector* G4eeToPGammaModel::PhysicsVector(G4double emin, |
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111 | G4double emax) const |
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112 | { |
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113 | G4double tmin = std::max(emin, ThresholdEnergy()); |
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114 | G4double tmax = std::max(tmin, emax); |
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115 | G4int nbins = (G4int)((tmax - tmin)/(5.*MeV)); |
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116 | G4PhysicsVector* v = new G4PhysicsLinearVector(emin,emax,nbins); |
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117 | v->SetSpline(true); |
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118 | return v; |
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119 | } |
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120 | |
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121 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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122 | |
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123 | void G4eeToPGammaModel::SampleSecondaries(std::vector<G4DynamicParticle*>* newp, |
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124 | G4double e, const G4ThreeVector& direction) |
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125 | { |
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126 | G4double egam = 0.5*e*(1.0 - massP*massP/(massR*massR)); |
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127 | G4double tkin = e - egam - massP; |
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128 | if(tkin < 0.0) tkin = 0.0; |
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129 | G4double cost; |
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130 | do { |
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131 | cost = 2.0*G4UniformRand() - 1.0; |
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132 | } while( 2.0*G4UniformRand() > 1.0 + cost*cost ); |
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133 | |
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134 | G4double sint = sqrt(1.0 - cost*cost); |
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135 | G4double phi = twopi * G4UniformRand(); |
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136 | |
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137 | G4ThreeVector dir(sint*cos(phi),sint*sin(phi), cost); |
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138 | dir.rotateUz(direction); |
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139 | |
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140 | // create G4DynamicParticle objects |
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141 | G4DynamicParticle* p1 = |
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142 | new G4DynamicParticle(particle,dir,tkin); |
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143 | G4DynamicParticle* p2 = |
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144 | new G4DynamicParticle(G4Gamma::Gamma(),-dir,egam); |
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145 | newp->push_back(p1); |
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146 | newp->push_back(p2); |
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147 | } |
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148 | |
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149 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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150 | |
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