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Please see the license in the file LICENSE and URL above * // * for the full disclaimer and the limitation of liability. * // * * // * This code implementation is the result of the scientific and * // * technical work of the GEANT4 collaboration. * // * By using, copying, modifying or distributing the software (or * // * any work based on the software) you agree to acknowledge its * // * use in resulting scientific publications, and indicate your * // * acceptance of all terms of the Geant4 Software license. * // ******************************************************************** // // $Id: G4PolarizedPairProductionCrossSection.cc,v 1.5 2007/11/01 17:32:34 schaelic Exp $ // GEANT4 tag $Name: geant4-09-02-ref-02 $ // // ------------------------------------------------------------------- // // GEANT4 Class file // // // File name: G4PolarizedPairProductionCrossSection // // Author: Andreas Schaelicke on the base of Karim Laihems code // // Creation date: 16.08.2006 // #include "G4PolarizedPairProductionCrossSection.hh" // #include "G4PolarizedGammaConversionModel.hh" // #include "G4Element.hh" G4bool G4PolarizedPairProductionCrossSection::scrnInitialized=false; G4double G4PolarizedPairProductionCrossSection::SCRN [3][20]; // screening function lookup table; void G4PolarizedPairProductionCrossSection::InitializeMe() { if (!scrnInitialized) { SCRN [1][1]= 0.5 ; SCRN [2][1] = 0.0145; SCRN [1][2]= 1.0 ; SCRN [2][2] = 0.0490; SCRN [1][3]= 2.0 ; SCRN [2][3] = 0.1400; SCRN [1][4]= 4.0 ; SCRN [2][4] = 0.3312; SCRN [1][5]= 8.0 ; SCRN [2][5] = 0.6758; SCRN [1][6]= 15.0 ; SCRN [2][6] = 1.126; SCRN [1][7]= 20.0 ; SCRN [2][7] = 1.367; SCRN [1][8]= 25.0 ; SCRN [2][8] = 1.564; SCRN [1][9]= 30.0 ; SCRN [2][9] = 1.731; SCRN [1][10]= 35.0 ; SCRN [2][10]= 1.875; SCRN [1][11]= 40.0 ; SCRN [2][11]= 2.001; SCRN [1][12]= 45.0 ; SCRN [2][12]= 2.114; SCRN [1][13]= 50.0 ; SCRN [2][13]= 2.216; SCRN [1][14]= 60.0 ; SCRN [2][14]= 2.393; SCRN [1][15]= 70.0 ; SCRN [2][15]= 2.545; SCRN [1][16]= 80.0 ; SCRN [2][16]= 2.676; SCRN [1][17]= 90.0 ; SCRN [2][17]= 2.793; SCRN [1][18]= 100.0 ; SCRN [2][18]= 2.897; SCRN [1][19]= 120.0 ; SCRN [2][19]= 3.078; scrnInitialized=true; } } G4PolarizedPairProductionCrossSection::G4PolarizedPairProductionCrossSection() { InitializeMe(); } void G4PolarizedPairProductionCrossSection::Initialize(G4double aGammaE, G4double aLept0E, G4double sintheta, const G4StokesVector & beamPol, const G4StokesVector & /*p1*/, G4int /*flag*/) { G4double aLept1E = aGammaE - aLept0E; G4double Stokes_P3 = beamPol.z() ; // ************************************************************************** G4double m0_c2 = electron_mass_c2; G4double Lept0E = aLept0E/m0_c2+1., Lept0E2 = Lept0E * Lept0E ; G4double GammaE = aGammaE/m0_c2; G4double Lept1E = aLept1E/m0_c2-1., Lept1E2 = Lept1E * Lept1E ; // const G4Element* theSelectedElement = theModel->SelectedAtom(); // ******* Gamma Transvers Momentum G4double TMom = std::sqrt(Lept0E2 -1.)* sintheta, u = TMom , u2 =u * u ; G4double Xsi = 1./(1.+u2) , Xsi2 = Xsi * Xsi ; // G4double theZ = theSelectedElement->GetZ(); // G4double fCoul = theSelectedElement->GetfCoulomb(); G4double delta = 12. * std::pow(theZ, 1./3.) * Lept0E * Lept1E * Xsi / (121. * GammaE); G4double GG=0.; if(delta < 0.5) { GG = std::log(2.* Lept0E * Lept1E / GammaE) - 2. - fCoul; } else if ( delta < 120) { for (G4int j=2; j<=19; j++) { if(SCRN[1][j] >= delta) { GG =std::log(2 * Lept0E * Lept1E / GammaE) - 2 - fCoul -(SCRN[2][j-1]+(delta-SCRN[1][j-1])*(SCRN[2][j]-SCRN[2][j-1])/(SCRN[1][j]-SCRN[1][j-1])); break; } } } else { G4double alpha_sc = (111 * std::pow(theZ, -1./3.)) / Xsi; GG = std::log(alpha_sc)- 2 - fCoul; } if(GG<-1) GG=-1; // *KL* do we need this ?! G4double I_Lepton = (Lept0E2 + Lept1E2)*(3+2*GG) + 2 * Lept0E * Lept1E * (1 + 4 * u2 * Xsi2 * GG); // G4double D_Lepton1 = -8 * Lept0E * Lept1E * u2 * Xsi2 * GG / I_Lepton; G4double L_Lepton1 = GammaE * ((Lept0E - Lept1E) * (3. + 2. * GG)+2 * Lept1E * (1 + 4 * u2 * Xsi2 * GG))/I_Lepton; G4double T_Lepton1 = 4 * GammaE * Lept1E * Xsi * u * (1. - 2. * Xsi) * GG / I_Lepton ; G4double Stokes_S1 = (Stokes_P3 * T_Lepton1) ; G4double Stokes_S2 = 0; G4double Stokes_S3 = (Stokes_P3 * L_Lepton1) ; theFinalElectronPolarization.setX(Stokes_S1); theFinalElectronPolarization.setY(Stokes_S2); theFinalElectronPolarization.setZ(Stokes_S3); if(theFinalElectronPolarization.mag2()>1) { G4cout<<" WARNING in pol-conv theFinalElectronPolarization \n"; G4cout <<"\t"<1) theFinalElectronPolarization.setZ(1); } G4double L_Lepton2 = GammaE * ((Lept1E - Lept0E) * (3. + 2. * GG)+2 * Lept0E * (1 + 4 * u2 * Xsi2 * GG))/I_Lepton; G4double T_Lepton2 = 4 * GammaE * Lept0E * Xsi * u * (1. - 2. * Xsi) * GG / I_Lepton ; G4double Stokes_SS1 = (Stokes_P3 * T_Lepton2) ; G4double Stokes_SS2 = 0; G4double Stokes_SS3 = (Stokes_P3 * L_Lepton2) ; theFinalPositronPolarization.SetPhoton(); theFinalPositronPolarization.setX(Stokes_SS1); theFinalPositronPolarization.setY(Stokes_SS2); theFinalPositronPolarization.setZ(Stokes_SS3); if(theFinalPositronPolarization.mag2()>1) { G4cout<<" WARNING in pol-conv theFinalPositronPolarization \n"; G4cout <<"\t"<