[819] | 1 | // |
---|
| 2 | // ******************************************************************** |
---|
| 3 | // * License and Disclaimer * |
---|
| 4 | // * * |
---|
| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
| 7 | // * conditions of the Geant4 Software License, included in the file * |
---|
| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
| 9 | // * include a list of copyright holders. * |
---|
| 10 | // * * |
---|
| 11 | // * Neither the authors of this software system, nor their employing * |
---|
| 12 | // * institutes,nor the agencies providing financial support for this * |
---|
| 13 | // * work make any representation or warranty, express or implied, * |
---|
| 14 | // * regarding this software system or assume any liability for its * |
---|
| 15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
| 16 | // * for the full disclaimer and the limitation of liability. * |
---|
| 17 | // * * |
---|
| 18 | // * This code implementation is the result of the scientific and * |
---|
| 19 | // * technical work of the GEANT4 collaboration. * |
---|
| 20 | // * By using, copying, modifying or distributing the software (or * |
---|
| 21 | // * any work based on the software) you agree to acknowledge its * |
---|
| 22 | // * use in resulting scientific publications, and indicate your * |
---|
| 23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
| 24 | // ******************************************************************** |
---|
| 25 | // |
---|
| 26 | // $Id: G4PolarizedPairProductionCrossSection.cc,v 1.5 2007/11/01 17:32:34 schaelic Exp $ |
---|
| 27 | // GEANT4 tag $Name: $ |
---|
| 28 | // |
---|
| 29 | // ------------------------------------------------------------------- |
---|
| 30 | // |
---|
| 31 | // GEANT4 Class file |
---|
| 32 | // |
---|
| 33 | // |
---|
| 34 | // File name: G4PolarizedPairProductionCrossSection |
---|
| 35 | // |
---|
| 36 | // Author: Andreas Schaelicke on the base of Karim Laihems code |
---|
| 37 | // |
---|
| 38 | // Creation date: 16.08.2006 |
---|
| 39 | // |
---|
| 40 | |
---|
| 41 | #include "G4PolarizedPairProductionCrossSection.hh" |
---|
| 42 | // #include "G4PolarizedGammaConversionModel.hh" |
---|
| 43 | // #include "G4Element.hh" |
---|
| 44 | |
---|
| 45 | G4bool G4PolarizedPairProductionCrossSection::scrnInitialized=false; |
---|
| 46 | G4double G4PolarizedPairProductionCrossSection::SCRN [3][20]; |
---|
| 47 | // screening function lookup table; |
---|
| 48 | |
---|
| 49 | void G4PolarizedPairProductionCrossSection::InitializeMe() |
---|
| 50 | { |
---|
| 51 | if (!scrnInitialized) { |
---|
| 52 | SCRN [1][1]= 0.5 ; SCRN [2][1] = 0.0145; |
---|
| 53 | SCRN [1][2]= 1.0 ; SCRN [2][2] = 0.0490; |
---|
| 54 | SCRN [1][3]= 2.0 ; SCRN [2][3] = 0.1400; |
---|
| 55 | SCRN [1][4]= 4.0 ; SCRN [2][4] = 0.3312; |
---|
| 56 | SCRN [1][5]= 8.0 ; SCRN [2][5] = 0.6758; |
---|
| 57 | SCRN [1][6]= 15.0 ; SCRN [2][6] = 1.126; |
---|
| 58 | SCRN [1][7]= 20.0 ; SCRN [2][7] = 1.367; |
---|
| 59 | SCRN [1][8]= 25.0 ; SCRN [2][8] = 1.564; |
---|
| 60 | SCRN [1][9]= 30.0 ; SCRN [2][9] = 1.731; |
---|
| 61 | SCRN [1][10]= 35.0 ; SCRN [2][10]= 1.875; |
---|
| 62 | SCRN [1][11]= 40.0 ; SCRN [2][11]= 2.001; |
---|
| 63 | SCRN [1][12]= 45.0 ; SCRN [2][12]= 2.114; |
---|
| 64 | SCRN [1][13]= 50.0 ; SCRN [2][13]= 2.216; |
---|
| 65 | SCRN [1][14]= 60.0 ; SCRN [2][14]= 2.393; |
---|
| 66 | SCRN [1][15]= 70.0 ; SCRN [2][15]= 2.545; |
---|
| 67 | SCRN [1][16]= 80.0 ; SCRN [2][16]= 2.676; |
---|
| 68 | SCRN [1][17]= 90.0 ; SCRN [2][17]= 2.793; |
---|
| 69 | SCRN [1][18]= 100.0 ; SCRN [2][18]= 2.897; |
---|
| 70 | SCRN [1][19]= 120.0 ; SCRN [2][19]= 3.078; |
---|
| 71 | |
---|
| 72 | scrnInitialized=true; |
---|
| 73 | } |
---|
| 74 | } |
---|
| 75 | |
---|
| 76 | G4PolarizedPairProductionCrossSection::G4PolarizedPairProductionCrossSection() |
---|
| 77 | { |
---|
| 78 | InitializeMe(); |
---|
| 79 | } |
---|
| 80 | |
---|
| 81 | |
---|
| 82 | void G4PolarizedPairProductionCrossSection::Initialize(G4double aGammaE, |
---|
| 83 | G4double aLept0E, |
---|
| 84 | G4double sintheta, |
---|
| 85 | const G4StokesVector & beamPol, |
---|
| 86 | const G4StokesVector & /*p1*/, |
---|
| 87 | G4int /*flag*/) |
---|
| 88 | { |
---|
| 89 | G4double aLept1E = aGammaE - aLept0E; |
---|
| 90 | |
---|
| 91 | G4double Stokes_P3 = beamPol.z() ; |
---|
| 92 | // ************************************************************************** |
---|
| 93 | |
---|
| 94 | G4double m0_c2 = electron_mass_c2; |
---|
| 95 | G4double Lept0E = aLept0E/m0_c2+1., Lept0E2 = Lept0E * Lept0E ; |
---|
| 96 | G4double GammaE = aGammaE/m0_c2; |
---|
| 97 | G4double Lept1E = aLept1E/m0_c2-1., Lept1E2 = Lept1E * Lept1E ; |
---|
| 98 | |
---|
| 99 | |
---|
| 100 | // const G4Element* theSelectedElement = theModel->SelectedAtom(); |
---|
| 101 | |
---|
| 102 | // ******* Gamma Transvers Momentum |
---|
| 103 | |
---|
| 104 | G4double TMom = std::sqrt(Lept0E2 -1.)* sintheta, u = TMom , u2 =u * u ; |
---|
| 105 | G4double Xsi = 1./(1.+u2) , Xsi2 = Xsi * Xsi ; |
---|
| 106 | |
---|
| 107 | // G4double theZ = theSelectedElement->GetZ(); |
---|
| 108 | |
---|
| 109 | // G4double fCoul = theSelectedElement->GetfCoulomb(); |
---|
| 110 | G4double delta = 12. * std::pow(theZ, 1./3.) * Lept0E * Lept1E * Xsi / (121. * GammaE); |
---|
| 111 | G4double GG=0.; |
---|
| 112 | |
---|
| 113 | if(delta < 0.5) { |
---|
| 114 | GG = std::log(2.* Lept0E * Lept1E / GammaE) - 2. - fCoul; |
---|
| 115 | } |
---|
| 116 | else if ( delta < 120) { |
---|
| 117 | for (G4int j=2; j<=19; j++) { |
---|
| 118 | if(SCRN[1][j] >= delta) { |
---|
| 119 | GG =std::log(2 * Lept0E * Lept1E / GammaE) - 2 - fCoul |
---|
| 120 | -(SCRN[2][j-1]+(delta-SCRN[1][j-1])*(SCRN[2][j]-SCRN[2][j-1])/(SCRN[1][j]-SCRN[1][j-1])); |
---|
| 121 | break; |
---|
| 122 | } |
---|
| 123 | } |
---|
| 124 | } |
---|
| 125 | else { |
---|
| 126 | G4double alpha_sc = (111 * std::pow(theZ, -1./3.)) / Xsi; |
---|
| 127 | GG = std::log(alpha_sc)- 2 - fCoul; |
---|
| 128 | } |
---|
| 129 | |
---|
| 130 | if(GG<-1) GG=-1; // *KL* do we need this ?! |
---|
| 131 | |
---|
| 132 | |
---|
| 133 | G4double I_Lepton = (Lept0E2 + Lept1E2)*(3+2*GG) + 2 * Lept0E * Lept1E * (1 + 4 * u2 * Xsi2 * GG); |
---|
| 134 | |
---|
| 135 | // G4double D_Lepton1 = -8 * Lept0E * Lept1E * u2 * Xsi2 * GG / I_Lepton; |
---|
| 136 | |
---|
| 137 | G4double L_Lepton1 = GammaE * ((Lept0E - Lept1E) * (3. + 2. * GG)+2 * Lept1E * (1 + 4 * u2 * Xsi2 * GG))/I_Lepton; |
---|
| 138 | |
---|
| 139 | G4double T_Lepton1 = 4 * GammaE * Lept1E * Xsi * u * (1. - 2. * Xsi) * GG / I_Lepton ; |
---|
| 140 | |
---|
| 141 | |
---|
| 142 | G4double Stokes_S1 = (Stokes_P3 * T_Lepton1) ; |
---|
| 143 | G4double Stokes_S2 = 0; |
---|
| 144 | G4double Stokes_S3 = (Stokes_P3 * L_Lepton1) ; |
---|
| 145 | |
---|
| 146 | |
---|
| 147 | theFinalElectronPolarization.setX(Stokes_S1); |
---|
| 148 | theFinalElectronPolarization.setY(Stokes_S2); |
---|
| 149 | theFinalElectronPolarization.setZ(Stokes_S3); |
---|
| 150 | |
---|
| 151 | if(theFinalElectronPolarization.mag2()>1) { |
---|
| 152 | G4cout<<" WARNING in pol-conv theFinalElectronPolarization \n"; |
---|
| 153 | G4cout |
---|
| 154 | <<"\t"<<theFinalElectronPolarization |
---|
| 155 | <<"\t GG\t"<<GG |
---|
| 156 | <<"\t delta\t"<<delta |
---|
| 157 | <<G4endl; |
---|
| 158 | theFinalElectronPolarization.setX(0); |
---|
| 159 | theFinalElectronPolarization.setY(0); |
---|
| 160 | theFinalElectronPolarization.setZ(Stokes_S3); |
---|
| 161 | if(Stokes_S3>1) theFinalElectronPolarization.setZ(1); |
---|
| 162 | } |
---|
| 163 | |
---|
| 164 | |
---|
| 165 | G4double L_Lepton2 = GammaE * ((Lept1E - Lept0E) * (3. + 2. * GG)+2 * Lept0E * (1 + 4 * u2 * Xsi2 * GG))/I_Lepton; |
---|
| 166 | |
---|
| 167 | G4double T_Lepton2 = 4 * GammaE * Lept0E * Xsi * u * (1. - 2. * Xsi) * GG / I_Lepton ; |
---|
| 168 | |
---|
| 169 | G4double Stokes_SS1 = (Stokes_P3 * T_Lepton2) ; |
---|
| 170 | G4double Stokes_SS2 = 0; |
---|
| 171 | G4double Stokes_SS3 = (Stokes_P3 * L_Lepton2) ; |
---|
| 172 | |
---|
| 173 | theFinalPositronPolarization.SetPhoton(); |
---|
| 174 | |
---|
| 175 | theFinalPositronPolarization.setX(Stokes_SS1); |
---|
| 176 | theFinalPositronPolarization.setY(Stokes_SS2); |
---|
| 177 | theFinalPositronPolarization.setZ(Stokes_SS3); |
---|
| 178 | |
---|
| 179 | if(theFinalPositronPolarization.mag2()>1) { |
---|
| 180 | G4cout<<" WARNING in pol-conv theFinalPositronPolarization \n"; |
---|
| 181 | G4cout |
---|
| 182 | <<"\t"<<theFinalPositronPolarization |
---|
| 183 | <<"\t GG\t"<<GG |
---|
| 184 | <<"\t delta\t"<<delta |
---|
| 185 | <<G4endl; |
---|
| 186 | } |
---|
| 187 | } |
---|
| 188 | |
---|
| 189 | G4double G4PolarizedPairProductionCrossSection::XSection(const G4StokesVector & /*pol2*/, |
---|
| 190 | const G4StokesVector & /*pol3*/) |
---|
| 191 | { |
---|
| 192 | G4cout<<"ERROR dummy routine G4PolarizedPairProductionCrossSection::XSection called \n"; |
---|
| 193 | return 0; |
---|
| 194 | } |
---|
| 195 | |
---|
| 196 | // return expected mean polarisation |
---|
| 197 | G4StokesVector G4PolarizedPairProductionCrossSection::GetPol2() |
---|
| 198 | { |
---|
| 199 | // electron/positron |
---|
| 200 | return theFinalElectronPolarization; |
---|
| 201 | } |
---|
| 202 | G4StokesVector G4PolarizedPairProductionCrossSection::GetPol3() |
---|
| 203 | { |
---|
| 204 | // photon |
---|
| 205 | return theFinalPositronPolarization;; |
---|
| 206 | } |
---|
| 207 | |
---|
| 208 | |
---|