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Please see the license in the file LICENSE and URL above * 16 // * for the full disclaimer and the limitatio 16 // * for the full disclaimer and the limitation of liability. * 17 // * 17 // * * 18 // * This code implementation is the result 18 // * This code implementation is the result of the scientific and * 19 // * technical work of the GEANT4 collaboratio 19 // * technical work of the GEANT4 collaboration. * 20 // * By using, copying, modifying or distri 20 // * By using, copying, modifying or distributing the software (or * 21 // * any work based on the software) you ag 21 // * any work based on the software) you agree to acknowledge its * 22 // * use in resulting scientific publicati 22 // * use in resulting scientific publications, and indicate your * 23 // * acceptance of all terms of the Geant4 Sof 23 // * acceptance of all terms of the Geant4 Software license. * 24 // ******************************************* 24 // ******************************************************************** 25 // 25 // >> 26 // $Id: G4hPairProductionModel.cc 97391 2016-06-02 10:08:45Z gcosmo $ 26 // 27 // 27 // ------------------------------------------- 28 // ------------------------------------------------------------------- 28 // 29 // 29 // GEANT4 Class file 30 // GEANT4 Class file 30 // 31 // 31 // 32 // 32 // File name: G4hPairProductionModel 33 // File name: G4hPairProductionModel 33 // 34 // 34 // Author: Vladimir Ivanchenko on base 35 // Author: Vladimir Ivanchenko on base of G4MuPairProductionModel 35 // 36 // 36 // Creation date: 28.02.2008 37 // Creation date: 28.02.2008 37 // 38 // 38 // Modifications: 39 // Modifications: 39 // 40 // 40 41 41 // 42 // 42 // Class Description: 43 // Class Description: 43 // 44 // 44 // 45 // 45 // ------------------------------------------- 46 // ------------------------------------------------------------------- 46 // 47 // 47 //....oooOO0OOooo........oooOO0OOooo........oo 48 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... 48 //....oooOO0OOooo........oooOO0OOooo........oo 49 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... 49 50 50 #include "G4hPairProductionModel.hh" 51 #include "G4hPairProductionModel.hh" >> 52 #include "G4PhysicalConstants.hh" >> 53 #include "G4Log.hh" >> 54 #include "G4Exp.hh" >> 55 >> 56 using namespace std; 51 57 52 G4hPairProductionModel::G4hPairProductionModel 58 G4hPairProductionModel::G4hPairProductionModel(const G4ParticleDefinition* p, 53 const G4String& nam) 59 const G4String& nam) 54 : G4MuPairProductionModel(p, nam) 60 : G4MuPairProductionModel(p, nam) 55 {} 61 {} >> 62 >> 63 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... >> 64 >> 65 G4hPairProductionModel::~G4hPairProductionModel() >> 66 {} >> 67 >> 68 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... >> 69 >> 70 G4double G4hPairProductionModel::ComputeDMicroscopicCrossSection( >> 71 G4double tkin, >> 72 G4double Z, >> 73 G4double pairEnergy) >> 74 // differential cross section >> 75 { >> 76 static const G4double bbbtf= 183. ; >> 77 static const G4double bbbh = 202.4 ; >> 78 static const G4double g1tf = 1.95e-5 ; >> 79 static const G4double g2tf = 5.3e-5 ; >> 80 static const G4double g1h = 4.4e-5 ; >> 81 static const G4double g2h = 4.8e-5 ; >> 82 >> 83 G4double totalEnergy = tkin + particleMass; >> 84 G4double residEnergy = totalEnergy - pairEnergy; >> 85 G4double massratio = particleMass/electron_mass_c2 ; >> 86 G4double massratio2 = massratio*massratio ; >> 87 G4double cross = 0.; >> 88 >> 89 G4double c3 = 0.75*sqrte*particleMass; >> 90 if (residEnergy <= c3*z13) { return cross; } >> 91 >> 92 G4double c7 = 4.*CLHEP::electron_mass_c2; >> 93 G4double c8 = 6.*particleMass*particleMass; >> 94 G4double alf = c7/pairEnergy; >> 95 G4double a3 = 1. - alf; >> 96 if (a3 <= 0.) { return cross; } >> 97 >> 98 // zeta calculation >> 99 G4double bbb,g1,g2; >> 100 if( Z < 1.5 ) { bbb = bbbh ; g1 = g1h ; g2 = g2h ; } >> 101 else { bbb = bbbtf; g1 = g1tf; g2 = g2tf; } >> 102 >> 103 G4double zeta = 0.; >> 104 G4double zeta1 = >> 105 0.073*G4Log(totalEnergy/(particleMass+g1*z23*totalEnergy))-0.26; >> 106 if ( zeta1 > 0.) >> 107 { >> 108 G4double zeta2 = >> 109 0.058*G4Log(totalEnergy/(particleMass+g2*z13*totalEnergy))-0.14; >> 110 zeta = zeta1/zeta2 ; >> 111 } >> 112 >> 113 G4double z2 = Z*(Z+zeta); >> 114 G4double screen0 = 2.*electron_mass_c2*sqrte*bbb/(z13*pairEnergy); >> 115 G4double a0 = totalEnergy*residEnergy; >> 116 G4double a1 = pairEnergy*pairEnergy/a0; >> 117 G4double bet = 0.5*a1; >> 118 G4double xi0 = 0.25*massratio2*a1; >> 119 G4double del = c8/a0; >> 120 >> 121 G4double rta3 = sqrt(a3); >> 122 G4double tmnexp = alf/(1. + rta3) + del*rta3; >> 123 if(tmnexp >= 1.0) { return cross; } >> 124 >> 125 G4double tmn = G4Log(tmnexp); >> 126 G4double sum = 0.; >> 127 >> 128 // Gaussian integration in ln(1-ro) ( with 8 points) >> 129 for (G4int i=0; i<8; i++) >> 130 { >> 131 G4double a4 = G4Exp(tmn*xgi[i]); // a4 = (1.-asymmetry) >> 132 G4double a5 = a4*(2.-a4) ; >> 133 G4double a6 = 1.-a5 ; >> 134 G4double a7 = 1.+a6 ; >> 135 G4double a9 = 3.+a6 ; >> 136 G4double xi = xi0*a5 ; >> 137 G4double xii = 1./xi ; >> 138 G4double xi1 = 1.+xi ; >> 139 G4double screen = screen0*xi1/a5 ; >> 140 G4double yeu = 5.-a6+4.*bet*a7 ; >> 141 G4double yed = 2.*(1.+3.*bet)*G4Log(3.+xii)-a6-a1*(2.-a6) ; >> 142 G4double ye1 = 1.+yeu/yed ; >> 143 G4double ale=G4Log(bbb/z13*sqrt(xi1*ye1)/(1.+screen*ye1)) ; >> 144 G4double cre = 0.5*G4Log(1.+2.25*z23*xi1*ye1/massratio2) ; >> 145 G4double be; >> 146 >> 147 if (xi <= 1.e3) { >> 148 be = ((2.+a6)*(1.+bet)+xi*a9)*G4Log(1.+xii)+(a5-bet)/xi1-a9; >> 149 } else { >> 150 be = (3.-a6+a1*a7)/(2.*xi); >> 151 } >> 152 G4double fe = (ale-cre)*be; >> 153 if ( fe < 0.) { fe = 0.; } >> 154 >> 155 G4double ymu = 4.+a6 +3.*bet*a7 ; >> 156 G4double ymd = a7*(1.5+a1)*G4Log(3.+xi)+1.-1.5*a6 ; >> 157 G4double ym1 = 1.+ymu/ymd ; >> 158 G4double alm_crm = G4Log(bbb*massratio/(1.5*z23*(1.+screen*ym1))); >> 159 G4double a10,bm; >> 160 if ( xi >= 1.e-3) >> 161 { >> 162 a10 = (1.+a1)*a5 ; >> 163 bm = (a7*(1.+1.5*bet)-a10*xii)*G4Log(xi1)+xi*(a5-bet)/xi1+a10; >> 164 } else { >> 165 bm = (5.-a6+bet*a9)*(xi/2.); >> 166 } >> 167 >> 168 G4double fm = alm_crm*bm; >> 169 if ( fm < 0.) { fm = 0.; } >> 170 >> 171 sum += wgi[i]*a4*(fe+fm/massratio2); >> 172 } >> 173 >> 174 cross = -tmn*sum*factorForCross*z2*residEnergy/(totalEnergy*pairEnergy); >> 175 >> 176 return cross; >> 177 } 56 178 57 //....oooOO0OOooo........oooOO0OOooo........oo 179 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... 58 180