00001 // 00002 // ******************************************************************** 00003 // * License and Disclaimer * 00004 // * * 00005 // * The Geant4 software is copyright of the Copyright Holders of * 00006 // * the Geant4 Collaboration. It is provided under the terms and * 00007 // * conditions of the Geant4 Software License, included in the file * 00008 // * LICENSE and available at http://cern.ch/geant4/license . These * 00009 // * include a list of copyright holders. * 00010 // * * 00011 // * Neither the authors of this software system, nor their employing * 00012 // * institutes,nor the agencies providing financial support for this * 00013 // * work make any representation or warranty, express or implied, * 00014 // * regarding this software system or assume any liability for its * 00015 // * use. Please see the license in the file LICENSE and URL above * 00016 // * for the full disclaimer and the limitation of liability. * 00017 // * * 00018 // * This code implementation is the result of the scientific and * 00019 // * technical work of the GEANT4 collaboration. * 00020 // * By using, copying, modifying or distributing the software (or * 00021 // * any work based on the software) you agree to acknowledge its * 00022 // * use in resulting scientific publications, and indicate your * 00023 // * acceptance of all terms of the Geant4 Software license. * 00024 // ******************************************************************** 00025 // 00026 // $Id: G4PolarizedComptonCrossSection.hh 69847 2013-05-16 09:36:18Z gcosmo $ 00027 // 00028 // GEANT4 Class file 00029 // 00030 // 00031 // File name: G4PolarizedComptonCrossSection 00032 // 00033 // Author: Andreas Schaelicke 00034 // 00035 // Creation date: 15.05.2005 00036 // 00037 // Modifications: 00038 // 18-07-06 use newly calculated cross sections (P. Starovoitov) 00039 // 21-08-06 update interface to geant4.8.1 (A. Schaelicke) 00040 // 15-10-07 introduced a more general framework for cross sections (AS) 00041 // 00042 // 00043 // Class Description: 00044 // determine the polarization of the final state 00045 // in a Compton scattering process employing the differential 00046 // cross section by F.W.Lipps & H.A.Tolhoek 00047 // ( Physica 20 (1954) 395 ) 00048 // 00049 #ifndef G4PolarizedComptonCrossSection_h 00050 #define G4PolarizedComptonCrossSection_h 1 00051 00052 #include "G4StokesVector.hh" 00053 #include "G4VPolarizedCrossSection.hh" 00054 00055 00056 00057 class G4PolarizedComptonCrossSection : public G4VPolarizedCrossSection 00058 { 00059 public: 00060 G4PolarizedComptonCrossSection(); 00061 virtual ~G4PolarizedComptonCrossSection(); 00062 public: 00063 // prepares the ingredients for the calculation of a polarization 00064 // dependent differential cross section 00065 // the kinematics is fixed (X - incoming photon energy in units of electron mass, eps - outgoing photon energy in unit of incoming photon energy, 00066 // and polarization of the incoming particles fixed (p0, p1) 00067 // a flag specifies the extent to which polarization is taken 00068 // into account 00069 virtual void Initialize(G4double eps, G4double X, G4double phi, 00070 const G4StokesVector & p0, 00071 const G4StokesVector & p1, 00072 G4int flag=0); 00073 00074 // returns the differential cross section for a given polarisation state 00075 // of the final state particles to be used in the calculation of the 00076 // polarization transfer 00077 // the calculation has to be initialised by calling Initialize() 00078 // prior to the first call of this function (see above) 00079 G4double XSection(const G4StokesVector & pol2,const G4StokesVector & pol3); 00080 // total cross section 00081 G4double TotalXSection(G4double xmin, G4double xmax, G4double y, 00082 const G4StokesVector & pol0,const G4StokesVector & pol1); 00083 00084 public: 00085 // return expected mean polarisation 00086 G4StokesVector GetPol2(); 00087 G4StokesVector GetPol3(); 00088 private: 00089 void DefineCoefficients(const G4StokesVector & pol0, 00090 const G4StokesVector & pol1); 00091 // states if an incoming or outgoing particle is polarized 00092 G4bool gammaPol2, electronPol3; 00093 00094 // these variables store the information necessary to evaluate the 00095 // differential cross section for arbitrary final state 00096 // polarizations (used in XSection): 00097 // - polarization independent part 00098 G4double phi0; 00099 // - part depending on the polarization of the final photon 00100 G4ThreeVector phi2; 00101 // - part depending on the polarization of the final electron 00102 G4ThreeVector phi3; 00103 // - product of polarizations of initial particles 00104 G4double polxx, polyy, polzz, polxz, polzx, polyz, polzy, polxy, polyx; 00105 00106 G4double diffXSFactor, totalXSFactor, re2; 00107 G4double polXS, unpXS; 00108 }; 00109 00110 00111 #endif