| 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: G4PolarizedBremsstrahlungModel
31 //
32 // Author: Karim Laihem
33
34 #include "G4PolarizedBremsstrahlungModel.hh"
35
36 #include "G4ParticleChangeForLoss.hh"
37 #include "G4PolarizationHelper.hh"
38 #include "G4PolarizedBremsstrahlungXS.hh"
39
40 G4PolarizedBremsstrahlungModel::G4PolarizedBremsstrahlungModel(
41 const G4ParticleDefinition* p, const G4String& nam)
42 : G4SeltzerBergerModel(p, nam)
43 , fCrossSectionCalculator(nullptr)
44 {}
45
46 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
47 G4PolarizedBremsstrahlungModel::~G4PolarizedBremsstrahlungModel()
48 {
49 if(fCrossSectionCalculator)
50 delete fCrossSectionCalculator;
51 }
52
53 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
54 void G4PolarizedBremsstrahlungModel::Initialise(const G4ParticleDefinition* p,
55 const G4DataVector& d)
56 {
57 G4SeltzerBergerModel::Initialise(p, d);
58 if(!fCrossSectionCalculator)
59 fCrossSectionCalculator = new G4PolarizedBremsstrahlungXS();
60 }
61
62 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
63 // The emitted gamma energy is sampled using a parametrized formula
64 void G4PolarizedBremsstrahlungModel::SampleSecondaries(
65 std::vector<G4DynamicParticle*>* vdp, const G4MaterialCutsCouple* couple,
66 const G4DynamicParticle* dp, G4double tmin, G4double maxEnergy)
67 {
68 G4SeltzerBergerModel::SampleSecondaries(vdp, couple, dp, tmin, maxEnergy);
69 std::size_t num = vdp->size();
70
71 if(num > 0)
72 {
73 G4double lepEnergy0 = dp->GetKineticEnergy();
74 G4double gamEnergy1 = (*vdp)[0]->GetKineticEnergy();
75 G4double sintheta =
76 dp->GetMomentumDirection().cross((*vdp)[0]->GetMomentumDirection()).mag();
77 if(sintheta > 1.)
78 sintheta = 1.;
79
80 G4StokesVector beamPol = G4StokesVector(dp->GetPolarization());
81
82 // determine interaction plane
83 G4ThreeVector nInteractionFrame = G4PolarizationHelper::GetFrame(
84 dp->GetMomentumDirection(),
85 fParticleChange->GetProposedMomentumDirection());
86
87 // transform polarization into interaction frame
88 beamPol.InvRotateAz(nInteractionFrame, dp->GetMomentumDirection());
89
90 // calculate polarization transfer
91 fCrossSectionCalculator->SetMaterial(
92 GetCurrentElement()->GetN(), // number of nucleons
93 GetCurrentElement()->GetZ(), GetCurrentElement()->GetfCoulomb());
94 fCrossSectionCalculator->Initialize(lepEnergy0, gamEnergy1, sintheta,
95 beamPol, G4StokesVector::ZERO);
96
97 // determine final state polarization
98 G4StokesVector newBeamPol = fCrossSectionCalculator->GetPol2();
99 newBeamPol.RotateAz(nInteractionFrame,
100 fParticleChange->GetProposedMomentumDirection());
101 fParticleChange->ProposePolarization(newBeamPol);
102
103 if(num != 1)
104 {
105 G4ExceptionDescription ed;
106 ed << num << " secondaries in polarized bremsstrahlung not supported!\n";
107 G4Exception("G4PolarizedBremsstrahlungModel::SampleSecondaries", "pol001",
108 JustWarning, ed);
109 }
110 for(std::size_t i = 0; i < num; ++i)
111 {
112 G4StokesVector photonPol = fCrossSectionCalculator->GetPol3();
113 photonPol.SetPhoton();
114 photonPol.RotateAz(nInteractionFrame, (*vdp)[i]->GetMomentumDirection());
115 (*vdp)[i]->SetPolarization(photonPol.p1(), photonPol.p2(),
116 photonPol.p3());
117 }
118 }
119 return;
120 }
121