Gabriele Cosmo
114 lines
4.6 KiB
C++
114 lines
4.6 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: G4PolarizedComptonCrossSection.hh,v 1.3 2007/11/01 17:32:34 schaelic Exp $
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// GEANT4 tag $Name: geant4-09-01 $
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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: G4PolarizedComptonCrossSection
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//
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// Author: Andreas Schaelicke
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//
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// Creation date: 15.05.2005
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//
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// Modifications:
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// 18-07-06 use newly calculated cross sections (P. Starovoitov)
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// 21-08-06 update interface to geant4.8.1 (A. Schaelicke)
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// 15-10-07 introduced a more general framework for cross sections (AS)
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//
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//
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// Class Description:
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// determine the polarization of the final state
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// in a Compton scattering process employing the differential
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// cross section by F.W.Lipps & H.A.Tolhoek
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// ( Physica 20 (1954) 395 )
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//
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#ifndef G4PolarizedComptonCrossSection_h
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#define G4PolarizedComptonCrossSection_h 1
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#include "G4StokesVector.hh"
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#include "G4VPolarizedCrossSection.hh"
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class G4PolarizedComptonCrossSection : public G4VPolarizedCrossSection
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{
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public:
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G4PolarizedComptonCrossSection();
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virtual ~G4PolarizedComptonCrossSection();
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public:
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// prepares the ingredients for the calculation of a polarization
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// dependent differential cross section
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// 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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// and polarization of the incoming particles fixed (p0, p1)
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// a flag specifies the extent to which polarization is taken
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// into account
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virtual void Initialize(G4double eps, G4double X, G4double phi,
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const G4StokesVector & p0,
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const G4StokesVector & p1,
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G4int flag=0);
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// returns the differential cross section for a given polarisation state
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// of the final state particles to be used in the calculation of the
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// polarization transfer
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// the calculation has to be initialised by calling Initialize()
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// prior to the first call of this function (see above)
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G4double XSection(const G4StokesVector & pol2,const G4StokesVector & pol3);
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// total cross section
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G4double TotalXSection(G4double xmin, G4double xmax, G4double y,
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const G4StokesVector & pol0,const G4StokesVector & pol1);
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public:
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// return expected mean polarisation
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G4StokesVector GetPol2();
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G4StokesVector GetPol3();
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private:
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void DefineCoefficients(const G4StokesVector & pol0,
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const G4StokesVector & pol1);
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// states if an incoming or outgoing particle is polarized
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G4bool gammaPol0, electronPol1, gammaPol2, electronPol3;
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// these variables store the information necessary to evaluate the
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// differential cross section for arbitrary final state
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// polarizations (used in XSection):
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// - polarization independent part
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G4double phi0;
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// - part depending on the polarization of the final photon
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G4ThreeVector phi2;
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// - part depending on the polarization of the final electron
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G4ThreeVector phi3;
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// - product of polarizations of initial particles
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G4double polxx, polyy, polzz, polxz, polzx, polyz, polzy, polxy, polyx;
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G4double diffXSFactor, totalXSFactor, re2;
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G4double epsilon, polXS, unpXS;
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};
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#endif
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