Geant4 Cross Reference |
1 // 1 2 // ******************************************* 3 // * License and Disclaimer 4 // * 5 // * The Geant4 software is copyright of th 6 // * the Geant4 Collaboration. It is provided 7 // * conditions of the Geant4 Software License 8 // * LICENSE and available at http://cern.ch/ 9 // * include a list of copyright holders. 10 // * 11 // * Neither the authors of this software syst 12 // * institutes,nor the agencies providing fin 13 // * work make any representation or warran 14 // * regarding this software system or assum 15 // * use. Please see the license in the file 16 // * for the full disclaimer and the limitatio 17 // * 18 // * This code implementation is the result 19 // * technical work of the GEANT4 collaboratio 20 // * By using, copying, modifying or distri 21 // * any work based on the software) you ag 22 // * use in resulting scientific publicati 23 // * acceptance of all terms of the Geant4 Sof 24 // ******************************************* 25 // 26 // 27 // ------------------------------------------- 28 // 29 // GEANT4 Class file 30 // 31 // 32 // File name: G4ModifiedTsai 33 // 34 // Author: Andreia Trindade (andreia@li 35 // Pedro Rodrigues (psilva@lip 36 // Luis Peralta (luis@lip.p 37 // 38 // Creation date: 21 March 2003 39 // 40 // Modifications: 41 // 21 Mar 2003 A.Trindade First implementation 42 // 24 Mar 2003 A.Trindade Fix in Tsai generato 43 // generation above pi 44 // 13 Oct 2010 V.Ivanchenko Moved to standar 45 // 26.04.2011 V.Grichine Clean-up of Pola 46 // 47 // Class Description: 48 // 49 // Bremsstrahlung Angular Distribution Generat 50 // suggested by L.Urban (Geant3 manual (1993) 51 // Derived from Tsai distribution (Rev Mod Phy 52 // 53 // Class Description: End 54 // 55 // ------------------------------------------- 56 // 57 58 #include "G4ModifiedTsai.hh" 59 #include "Randomize.hh" 60 #include "G4Log.hh" 61 #include <CLHEP/Units/PhysicalConstants.h> 62 63 //....oooOO0OOooo........oooOO0OOooo........oo 64 65 G4ModifiedTsai::G4ModifiedTsai(const G4String& 66 : G4VEmAngularDistribution("ModifiedTsai") 67 {} 68 69 //....oooOO0OOooo........oooOO0OOooo........oo 70 71 G4ModifiedTsai::~G4ModifiedTsai() = default; 72 73 //....oooOO0OOooo........oooOO0OOooo........oo 74 75 G4ThreeVector& 76 G4ModifiedTsai::SampleDirection(const G4Dynami 77 G4double, G4in 78 { 79 // Sample gamma angle (Z - axis along the pa 80 G4double cost = SampleCosTheta(dp->GetKineti 81 G4double sint = std::sqrt((1 - cost)*(1 + co 82 G4double phi = CLHEP::twopi*G4UniformRand() 83 84 fLocalDirection.set(sint*std::cos(phi), sint 85 fLocalDirection.rotateUz(dp->GetMomentumDire 86 87 return fLocalDirection; 88 } 89 90 //....oooOO0OOooo........oooOO0OOooo........oo 91 92 G4double G4ModifiedTsai::SampleCosTheta(G4doub 93 { 94 // Universal distribution suggested by L. Ur 95 // Phys211) derived from Tsai distribution ( 96 97 G4double uMax = 2*(1. + kinEnergy/CLHEP::ele 98 99 static const G4double a1 = 1.6; 100 static const G4double a2 = a1/3.; 101 static const G4double border = 0.25; 102 G4double u; 103 CLHEP::HepRandomEngine* rndmEngine = G4Rando 104 105 do { 106 G4double uu = -G4Log(rndmEngine->flat()*rn 107 u = (border > rndmEngine->flat()) ? uu*a1 108 109 // Loop checking, 03-Aug-2015, Vladimir Iv 110 } while(u > uMax); 111 112 return 1.0 - 2.0*u*u/(uMax*uMax); 113 } 114 115 //....oooOO0OOooo........oooOO0OOooo........oo 116 117 void G4ModifiedTsai::SamplePairDirections(cons 118 G4double elecKinEnergy, 119 G4double posiKinEnergy, 120 G4ThreeVector& dirElectron, 121 G4ThreeVector& dirPositron, 122 G4int, const G4Material*) 123 { 124 G4double phi = CLHEP::twopi * G4UniformRand 125 G4double sinp = std::sin(phi); 126 G4double cosp = std::cos(phi); 127 128 G4double cost = SampleCosTheta(elecKinEnergy 129 G4double sint = std::sqrt((1. - cost)*(1. + 130 131 dirElectron.set(sint*cosp, sint*sinp, cost); 132 dirElectron.rotateUz(dp->GetMomentumDirectio 133 134 cost = SampleCosTheta(posiKinEnergy); 135 sint = std::sqrt((1. - cost)*(1. + cost)); 136 137 dirPositron.set(-sint*cosp, -sint*sinp, cost 138 dirPositron.rotateUz(dp->GetMomentumDirectio 139 } 140 141 //....oooOO0OOooo........oooOO0OOooo........oo 142 143 void G4ModifiedTsai::PrintGeneratorInformation 144 { 145 G4cout << "\n" << G4endl; 146 G4cout << "Bremsstrahlung Angular Generator 147 G4cout << "Distribution suggested by L.Urban 148 << G4endl; 149 G4cout << "Derived from Tsai distribution (R 150 << G4endl; 151 } 152 153 //....oooOO0OOooo........oooOO0OOooo........oo 154