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G4ePolarizedBremsstrahlungModel.cc
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25 //
26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4ePolarizedBremsstrahlungModel
33 //
34 // Author: Karim Laihem
35 //
36 // Creation date: 12.03.2005
37 //
38 // Modifications:
39 // 19-08-06 addapted to accomodate geant481 structure
40 //
41 //
42 // Class Description:
43 //
44 //
45 // -------------------------------------------------------------------
46 //
47 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
48 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
49 
50 #include "G4ePolarizedBremsstrahlungModel.hh"
51 #include "G4PolarizedBremsstrahlungCrossSection.hh"
52 #include "G4ParticleChangeForLoss.hh"
53 #include "G4PolarizationHelper.hh"
54 
55 G4ePolarizedBremsstrahlungModel::G4ePolarizedBremsstrahlungModel(
56  const G4ParticleDefinition* p, const G4String& nam)
57  : G4SeltzerBergerModel(p,nam),
58  crossSectionCalculator(nullptr)
59 {
60 }
61 
62 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
63 
64 G4ePolarizedBremsstrahlungModel::~G4ePolarizedBremsstrahlungModel()
65 {
66  if (crossSectionCalculator) delete crossSectionCalculator;
67 }
68 
69 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
70 
71 void G4ePolarizedBremsstrahlungModel::Initialise(const G4ParticleDefinition* p,
72  const G4DataVector& d)
73 {
74  G4SeltzerBergerModel::Initialise(p,d);
75  if (!crossSectionCalculator)
76  crossSectionCalculator = new G4PolarizedBremsstrahlungCrossSection();
77 }
78 
79 
80 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
81 
82 
83 void G4ePolarizedBremsstrahlungModel::SampleSecondaries(std::vector<G4DynamicParticle*>* vdp,
84  const G4MaterialCutsCouple* couple,
85  const G4DynamicParticle* dp,
86  G4double tmin,
87  G4double maxEnergy)
88 {
89  G4SeltzerBergerModel::SampleSecondaries(vdp,couple,dp,tmin,maxEnergy);
90  G4int num = vdp->size();
91 
92  if(num > 0) {
93  G4double lepEnergy0 = dp->GetKineticEnergy();
94  G4double gamEnergy1 = (*vdp)[0]->GetKineticEnergy();
95  G4double sintheta = dp->GetMomentumDirection().cross((*vdp)[0]->GetMomentumDirection()).mag();
96  if (sintheta>1.) sintheta=1.;
97 
98 
99  G4StokesVector beamPol = dp->GetPolarization();
100 
101  // determine interaction plane
102  G4ThreeVector nInteractionFrame =
103  G4PolarizationHelper::GetFrame(dp->GetMomentumDirection(),
104  fParticleChange->GetProposedMomentumDirection());
105 
106  // transform polarization into interaction frame
107  beamPol.InvRotateAz(nInteractionFrame,dp->GetMomentumDirection());
108 
109  // calulcate polarization transfer
110  crossSectionCalculator->SetMaterial(GetCurrentElement()->GetN(), // number of nucleons
111  GetCurrentElement()->GetZ(),
112  GetCurrentElement()->GetfCoulomb());
113  crossSectionCalculator->Initialize(lepEnergy0, gamEnergy1, sintheta,
114  beamPol, G4StokesVector::ZERO);
115 
116  // deterimine final state polarization
117  G4StokesVector newBeamPol = crossSectionCalculator->GetPol2();
118  newBeamPol.RotateAz(nInteractionFrame,
119  fParticleChange->GetProposedMomentumDirection());
120  fParticleChange->ProposePolarization(newBeamPol);
121 
122  if (num!=1) G4cout<<" WARNING "<<num<<" secondaries in polarized bremsstrahlung not supported!\n";
123  for (G4int i=0; i<num; i++) {
124  G4StokesVector photonPol = crossSectionCalculator->GetPol3();
125  photonPol.SetPhoton();
126  photonPol.RotateAz(nInteractionFrame,(*vdp)[i]->GetMomentumDirection());
127  (*vdp)[i]->SetPolarization(photonPol.p1(),
128  photonPol.p2(),
129  photonPol.p3());
130  }
131  }
132  return;
133 }
134 // The emitted gamma energy is sampled using a parametrized formula