Gabriele Cosmo
215 lines
7.8 KiB
C++
215 lines
7.8 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// $Id: G4PolarizedBremsstrahlungCrossSection.cc 96114 2016-03-16 18:51:33Z gcosmo $
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//
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// -------------------------------------------------------------------
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//
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// GEANT4 Class file
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//
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//
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// File name: G4PolarizedBremsstrahlungCrossSection
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//
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// Author: Andreas Schaelicke on the base of Karim Laihems code
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//
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// Creation date: 16.08.2006
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//
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#include "G4PolarizedBremsstrahlungCrossSection.hh"
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#include "G4PhysicalConstants.hh"
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G4bool G4PolarizedBremsstrahlungCrossSection::scrnInitialized=false;
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G4double G4PolarizedBremsstrahlungCrossSection::SCRN [3][20];
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// screening function lookup table;
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void G4PolarizedBremsstrahlungCrossSection::InitializeMe()
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{
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if (!scrnInitialized) {
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SCRN [1][1]= 0.5 ; SCRN [2][1] = 0.0145;
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SCRN [1][2]= 1.0 ; SCRN [2][2] = 0.0490;
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SCRN [1][3]= 2.0 ; SCRN [2][3] = 0.1400;
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SCRN [1][4]= 4.0 ; SCRN [2][4] = 0.3312;
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SCRN [1][5]= 8.0 ; SCRN [2][5] = 0.6758;
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SCRN [1][6]= 15.0 ; SCRN [2][6] = 1.126;
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SCRN [1][7]= 20.0 ; SCRN [2][7] = 1.367;
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SCRN [1][8]= 25.0 ; SCRN [2][8] = 1.564;
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SCRN [1][9]= 30.0 ; SCRN [2][9] = 1.731;
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SCRN [1][10]= 35.0 ; SCRN [2][10]= 1.875;
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SCRN [1][11]= 40.0 ; SCRN [2][11]= 2.001;
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SCRN [1][12]= 45.0 ; SCRN [2][12]= 2.114;
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SCRN [1][13]= 50.0 ; SCRN [2][13]= 2.216;
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SCRN [1][14]= 60.0 ; SCRN [2][14]= 2.393;
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SCRN [1][15]= 70.0 ; SCRN [2][15]= 2.545;
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SCRN [1][16]= 80.0 ; SCRN [2][16]= 2.676;
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SCRN [1][17]= 90.0 ; SCRN [2][17]= 2.793;
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SCRN [1][18]= 100.0 ; SCRN [2][18]= 2.897;
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SCRN [1][19]= 120.0 ; SCRN [2][19]= 3.078;
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scrnInitialized=true;
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}
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}
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G4PolarizedBremsstrahlungCrossSection::G4PolarizedBremsstrahlungCrossSection()
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{
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InitializeMe();
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}
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void G4PolarizedBremsstrahlungCrossSection::Initialize(
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G4double aLept0E, G4double aGammaE, G4double sintheta,
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const G4StokesVector & beamPol,
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const G4StokesVector & /*p1*/,
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G4int /*flag*/)
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{
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// G4cout<<"G4PolarizedBremsstrahlungCrossSection::Initialize \n"
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// <<"lepE = "<<aLept0E
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// <<"gamE = "<<aGammaE
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// <<"sint = "<<sintheta<<"\n"
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// <<"beamPol="<<beamPol<<"\n";
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G4double aLept1E = aLept0E - aGammaE;
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G4double Stokes_S1 = beamPol.x() ;
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G4double Stokes_S2 = beamPol.y() ;
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G4double Stokes_S3 = beamPol.z() ;
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// **************************************************************************
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G4double m0_c2 = electron_mass_c2;
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G4double Lept0E = aLept0E/m0_c2+1., Lept0E2 = Lept0E * Lept0E ;
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G4double GammaE = aGammaE/m0_c2, GammaE2 = GammaE * GammaE ;
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G4double Lept1E = aLept1E/m0_c2+1., Lept1E2 = Lept1E * Lept1E ;
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// const G4Element* theSelectedElement = theModel->SelectedAtom();
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// ******* Gamma Transvers Momentum
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G4double TMom = std::sqrt(Lept0E2 -1.)* sintheta;
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G4double u = TMom , u2 =u * u ;
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G4double Xsi = 1./(1.+u2) , Xsi2 = Xsi * Xsi ;
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// G4double theZ = theSelectedElement->GetZ();
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// G4double fCoul = theSelectedElement->GetfCoulomb();
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G4double delta = 12. * std::pow(theZ, 1./3.) *
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Lept0E * Lept1E * Xsi / (121. * GammaE);
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G4double GG=0.;
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if(delta < 0.5) {
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GG = std::log(2.* Lept0E * Lept1E / GammaE) - 2. - fCoul;
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}
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else if ( delta < 120) {
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for (G4int j=2; j<=19; j++) {
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if(SCRN[1][j] >= delta) {
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GG =std::log(2 * Lept0E * Lept1E / GammaE) - 2 - fCoul
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-(SCRN[2][j-1]+(delta-SCRN[1][j-1])*(SCRN[2][j]-SCRN[2][j-1])
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/(SCRN[1][j]-SCRN[1][j-1]));
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break;
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}
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}
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}
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else {
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G4double alpha_sc = (111. * std::pow(theZ, -1./3.)) / Xsi;
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GG = std::log(alpha_sc)- 2. - fCoul;
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}
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if(GG<-1.) GG=-1.; // *KL* do we need this ?!
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G4double I_Lept = (Lept0E2 + Lept1E2) * (3.+2.*GG) - 2 * Lept0E * Lept1E * (1. + 4. * u2 * Xsi2 * GG);
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G4double F_Lept = Lept1E * 4. * GammaE * u * Xsi * (1. - 2 * Xsi) * GG / I_Lept;
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G4double E_Lept = Lept0E * 4. * GammaE * u * Xsi * (2. * Xsi - 1.) * GG / I_Lept;
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G4double M_Lept = 4. * Lept0E * Lept1E * (1. + GG - 2. * Xsi2 * u2 * GG) / I_Lept ;
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G4double P_Lept = GammaE2 * (1. + 8. * GG * (Xsi - 0.5)*(Xsi - 0.5)) / I_Lept ;
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G4double Stokes_SS1 = M_Lept * Stokes_S1 + E_Lept * Stokes_S3;
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G4double Stokes_SS2 = M_Lept * Stokes_S2 ;
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G4double Stokes_SS3 = (M_Lept + P_Lept) * Stokes_S3 + F_Lept * Stokes_S1;
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theFinalLeptonPolarization.setX(Stokes_SS1);
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theFinalLeptonPolarization.setY(Stokes_SS2);
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theFinalLeptonPolarization.setZ(Stokes_SS3);
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if(theFinalLeptonPolarization.mag2()>1) {
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G4cout<<" WARNING in pol-brem theFinalLeptonPolarization \n";
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G4cout
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<<"\t"<<theFinalLeptonPolarization
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<<"\t GG\t"<<GG
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<<"\t delta\t"<<delta
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<<G4endl;
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theFinalLeptonPolarization.setX(0);
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theFinalLeptonPolarization.setY(0);
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theFinalLeptonPolarization.setZ(Stokes_SS3);
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if(Stokes_SS3>1) theFinalLeptonPolarization.setZ(1);
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}
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G4double I_Gamma = (Lept0E2 + Lept1E2)*(3.+2.*GG) - 2. * Lept0E * Lept1E * (1. + 4. * u2 * Xsi2 * GG);
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G4double D_Gamma = 8. * Lept0E * Lept1E * u2 * Xsi2 * GG / I_Gamma;
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G4double L_Gamma = GammaE * ((Lept0E + Lept1E) * (3. + 2. * GG)
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- 2. * Lept1E * (1. + 4. * u2 * Xsi2 * GG))/I_Gamma;
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G4double T_Gamma = 4. * GammaE * Lept1E * Xsi * u * (2. * Xsi - 1.) * GG / I_Gamma ;
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G4double Stokes_P1 = D_Gamma ;
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G4double Stokes_P2 = 0.;
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G4double Stokes_P3 = (Stokes_S3*L_Gamma + Stokes_S1*T_Gamma) ;
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theFinalGammaPolarization.SetPhoton();
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theFinalGammaPolarization.setX(Stokes_P1);
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theFinalGammaPolarization.setY(Stokes_P2);
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theFinalGammaPolarization.setZ(Stokes_P3);
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if(theFinalGammaPolarization.mag2()>1) {
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G4cout<<" WARNING in pol-brem theFinalGammaPolarization \n";
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G4cout
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<<"\t"<<theFinalGammaPolarization
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<<"\t GG\t"<<GG
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<<"\t delta\t"<<delta
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<<G4endl;
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}
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}
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G4double G4PolarizedBremsstrahlungCrossSection::XSection(const G4StokesVector & /*pol2*/,
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const G4StokesVector & /*pol3*/)
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{
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G4cout<<"ERROR dummy routine G4PolarizedBremsstrahlungCrossSection::XSection called \n";
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return 0.;
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}
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// return expected mean polarisation
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G4StokesVector G4PolarizedBremsstrahlungCrossSection::GetPol2()
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{
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// electron/positron
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return theFinalLeptonPolarization;
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}
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G4StokesVector G4PolarizedBremsstrahlungCrossSection::GetPol3()
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{
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// photon
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return theFinalGammaPolarization;;
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}
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