1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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7 | // * conditions of the Geant4 Software License, included in the file * |
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8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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9 | // * include a list of copyright holders. * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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12 | // * institutes,nor the agencies providing financial support for this * |
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13 | // * work make any representation or warranty, express or implied, * |
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14 | // * regarding this software system or assume any liability for its * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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16 | // * for the full disclaimer and the limitation of liability. * |
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17 | // * * |
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18 | // * This code implementation is the result of the scientific and * |
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19 | // * technical work of the GEANT4 collaboration. * |
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20 | // * By using, copying, modifying or distributing the software (or * |
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21 | // * any work based on the software) you agree to acknowledge its * |
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22 | // * use in resulting scientific publications, and indicate your * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | // $Id: G4PolarizedComptonCrossSection.hh,v 1.3 2007/11/01 17:32:34 schaelic Exp $ |
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27 | // GEANT4 tag $Name: geant4-09-03 $ |
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28 | // |
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29 | // GEANT4 Class file |
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30 | // |
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31 | // |
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32 | // File name: G4PolarizedComptonCrossSection |
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33 | // |
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34 | // Author: Andreas Schaelicke |
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35 | // |
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36 | // Creation date: 15.05.2005 |
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37 | // |
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38 | // Modifications: |
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39 | // 18-07-06 use newly calculated cross sections (P. Starovoitov) |
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40 | // 21-08-06 update interface to geant4.8.1 (A. Schaelicke) |
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41 | // 15-10-07 introduced a more general framework for cross sections (AS) |
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42 | // |
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43 | // |
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44 | // Class Description: |
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45 | // determine the polarization of the final state |
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46 | // in a Compton scattering process employing the differential |
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47 | // cross section by F.W.Lipps & H.A.Tolhoek |
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48 | // ( Physica 20 (1954) 395 ) |
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49 | // |
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50 | #ifndef G4PolarizedComptonCrossSection_h |
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51 | #define G4PolarizedComptonCrossSection_h 1 |
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52 | |
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53 | #include "G4StokesVector.hh" |
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54 | #include "G4VPolarizedCrossSection.hh" |
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55 | |
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56 | |
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57 | |
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58 | class G4PolarizedComptonCrossSection : public G4VPolarizedCrossSection |
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59 | { |
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60 | public: |
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61 | G4PolarizedComptonCrossSection(); |
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62 | virtual ~G4PolarizedComptonCrossSection(); |
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63 | public: |
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64 | // prepares the ingredients for the calculation of a polarization |
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65 | // dependent differential cross section |
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66 | // the kinematics is fixed (X - incoming photon energy in units of electron mass, eps - outgoing photon energy in unit of incoming photon energy, |
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67 | // and polarization of the incoming particles fixed (p0, p1) |
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68 | // a flag specifies the extent to which polarization is taken |
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69 | // into account |
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70 | virtual void Initialize(G4double eps, G4double X, G4double phi, |
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71 | const G4StokesVector & p0, |
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72 | const G4StokesVector & p1, |
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73 | G4int flag=0); |
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74 | |
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75 | // returns the differential cross section for a given polarisation state |
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76 | // of the final state particles to be used in the calculation of the |
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77 | // polarization transfer |
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78 | // the calculation has to be initialised by calling Initialize() |
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79 | // prior to the first call of this function (see above) |
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80 | G4double XSection(const G4StokesVector & pol2,const G4StokesVector & pol3); |
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81 | // total cross section |
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82 | G4double TotalXSection(G4double xmin, G4double xmax, G4double y, |
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83 | const G4StokesVector & pol0,const G4StokesVector & pol1); |
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84 | |
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85 | public: |
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86 | // return expected mean polarisation |
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87 | G4StokesVector GetPol2(); |
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88 | G4StokesVector GetPol3(); |
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89 | private: |
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90 | void DefineCoefficients(const G4StokesVector & pol0, |
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91 | const G4StokesVector & pol1); |
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92 | // states if an incoming or outgoing particle is polarized |
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93 | G4bool gammaPol0, electronPol1, gammaPol2, electronPol3; |
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94 | |
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95 | |
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96 | // these variables store the information necessary to evaluate the |
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97 | // differential cross section for arbitrary final state |
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98 | // polarizations (used in XSection): |
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99 | // - polarization independent part |
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100 | G4double phi0; |
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101 | // - part depending on the polarization of the final photon |
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102 | G4ThreeVector phi2; |
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103 | // - part depending on the polarization of the final electron |
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104 | G4ThreeVector phi3; |
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105 | // - product of polarizations of initial particles |
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106 | G4double polxx, polyy, polzz, polxz, polzx, polyz, polzy, polxy, polyx; |
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107 | |
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108 | G4double diffXSFactor, totalXSFactor, re2; |
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109 | G4double epsilon, polXS, unpXS; |
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110 | }; |
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111 | |
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112 | |
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113 | #endif |
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