| Geant4 Cross Reference |
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 // -------------------------------------------------------------------
27 //
28 // Geant4 Class file
29 //
30 // File name: G4PolarizedPhotoElectricModel
31 //
32 // Author: Andreas Schaelicke & Karim Laihem
33 //
34 // Class Description:
35 // Implementation of Photo electric effect
36 // including polarization transfer from circularly polarised gammas
37
38 #include "G4PolarizedPhotoElectricModel.hh"
39
40 #include "G4DataVector.hh"
41 #include "G4ParticleChangeForGamma.hh"
42 #include "G4PolarizationHelper.hh"
43 #include "G4PolarizedPhotoElectricXS.hh"
44
45 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
46 G4PolarizedPhotoElectricModel::G4PolarizedPhotoElectricModel(
47 const G4ParticleDefinition*, const G4String& nam)
48 : G4PEEffectFluoModel(nam)
49 , fCrossSectionCalculator(nullptr)
50 , fVerboseLevel(0)
51 {}
52
53 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
54 G4PolarizedPhotoElectricModel::~G4PolarizedPhotoElectricModel()
55 {
56 if(fCrossSectionCalculator)
57 delete fCrossSectionCalculator;
58 }
59
60 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
61 void G4PolarizedPhotoElectricModel::Initialise(const G4ParticleDefinition* pd,
62 const G4DataVector& dv)
63 {
64 G4PEEffectFluoModel::Initialise(pd, dv);
65 if(!fCrossSectionCalculator)
66 fCrossSectionCalculator = new G4PolarizedPhotoElectricXS();
67 }
68
69 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
70 void G4PolarizedPhotoElectricModel::SampleSecondaries(
71 std::vector<G4DynamicParticle*>* vdp, const G4MaterialCutsCouple* couple,
72 const G4DynamicParticle* dp, G4double tmin, G4double maxEnergy)
73 {
74 G4PEEffectFluoModel::SampleSecondaries(vdp, couple, dp, tmin, maxEnergy);
75
76 if(fVerboseLevel >= 1)
77 {
78 G4cout << "G4PolarizedPhotoElectricModel::SampleSecondaries" << G4endl;
79 }
80
81 if(vdp && !vdp->empty())
82 {
83 G4double gamEnergy0 = dp->GetKineticEnergy();
84 G4double lepEnergy1 = (*vdp)[0]->GetKineticEnergy();
85 G4double sintheta =
86 dp->GetMomentumDirection().cross((*vdp)[0]->GetMomentumDirection()).mag();
87 if(sintheta > 1.)
88 sintheta = 1.;
89
90 G4StokesVector beamPol = G4StokesVector(dp->GetPolarization());
91 beamPol.SetPhoton();
92
93 // determine interaction plane
94 G4ThreeVector nInteractionFrame = G4PolarizationHelper::GetFrame(
95 dp->GetMomentumDirection(), (*vdp)[0]->GetMomentumDirection());
96 if(dp->GetMomentumDirection()
97 .cross((*vdp)[0]->GetMomentumDirection())
98 .mag() < 1.e-10)
99 {
100 nInteractionFrame =
101 G4PolarizationHelper::GetRandomFrame(dp->GetMomentumDirection());
102 }
103
104 // transform polarization into interaction frame
105 beamPol.InvRotateAz(nInteractionFrame, dp->GetMomentumDirection());
106
107 // calulcate polarization transfer
108 fCrossSectionCalculator->SetMaterial(
109 GetCurrentElement()->GetN(), // number of nucleons
110 GetCurrentElement()->GetZ(), GetCurrentElement()->GetfCoulomb());
111 fCrossSectionCalculator->Initialize(gamEnergy0, lepEnergy1, sintheta,
112 beamPol, G4StokesVector::ZERO);
113
114 // determine final state polarization
115 G4StokesVector lep1Pol = fCrossSectionCalculator->GetPol2();
116 lep1Pol.RotateAz(nInteractionFrame, (*vdp)[0]->GetMomentumDirection());
117 (*vdp)[0]->SetPolarization(lep1Pol.p1(), lep1Pol.p2(), lep1Pol.p3());
118
119 if(vdp->size() != 1)
120 {
121 G4ExceptionDescription ed;
122 ed << " WARNING " << vdp->size()
123 << " secondaries in polarized photo electric effect not supported!\n";
124 G4Exception("G4PolarizedPhotoElectricModel::SampleSecondaries", "pol024",
125 JustWarning, ed);
126 }
127 }
128 }
129