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25 //
26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class header file
30 //
31 //
32 // File name: G4eplusTo2or3GammaModel
33 //
34 // Author: Vladimir Ivanchenko and Omrane Kadri
35 //
36 // Creation date: 29.03.2018
37 //
38 //
39 // Class Description:
40 //
41 // Implementation of e+ annihilation into 2 or 3 gamma on fly
42 // Annihilation at rest is sampled by G4VPositronAtRestModel
43 // Implementation of 3-gamma annihilation is performed by
44 // G4eplusTo3GammaOKVIModel. Cross section of both models
45 // depend on cut parameter fDelta, which defines relative low-energy
46 // limit on 3d gamma energy. For computation of the cross section
47 // next to leading order radiative corrections are taken into account,
48 // atomic effects at low-energy are not considered.
49 //
50 // V.N.Baier, V.S. Fadin, V.A. Khose, E.A. Kuraev,
51 // Physics Reports 78 (1981) 293-393.
52 //
53 // -------------------------------------------------------------------
54 //
55
56 #ifndef G4eplusTo2or3GammaModel_h
57 #define G4eplusTo2or3GammaModel_h 1
58
59 #include "G4VEmModel.hh"
60
61 class G4eplusTo3GammaOKVIModel;
62 class G4ParticleChangeForGamma;
63 class G4PhysicsVector;
64 class G4DataVector;
65
66 class G4eplusTo2or3GammaModel : public G4VEmModel
67 {
68
69 public:
70
71 G4eplusTo2or3GammaModel();
72
73 ~G4eplusTo2or3GammaModel() override;
74
75 void Initialise(const G4ParticleDefinition*, const G4DataVector&) override;
76
77 G4double ComputeCrossSectionPerElectron(G4double kinEnergy);
78
79 G4double ComputeCrossSectionPerAtom(
80 const G4ParticleDefinition*,
81 G4double kinEnergy,
82 G4double Z,
83 G4double A = 0.,
84 G4double cutEnergy = 0.,
85 G4double maxEnergy = DBL_MAX) override;
86
87 G4double CrossSectionPerVolume(const G4Material*,
88 const G4ParticleDefinition*,
89 G4double kineticEnergy,
90 G4double cutEnergy = 0.0,
91 G4double maxEnergy = DBL_MAX) override;
92
93 void SampleSecondaries(std::vector<G4DynamicParticle*>*,
94 const G4MaterialCutsCouple*,
95 const G4DynamicParticle*,
96 G4double tmin = 0.0,
97 G4double maxEnergy = DBL_MAX) override;
98
99 void SetDelta(G4double val) { if(val > 0.0) { fDeltaMin = val; } };
100
101 // hide assignment operator
102 G4eplusTo2or3GammaModel & operator=
103 (const G4eplusTo2or3GammaModel &right) = delete;
104 G4eplusTo2or3GammaModel(const G4eplusTo2or3GammaModel&) = delete;
105
106 private:
107
108 const G4ParticleDefinition* theGamma;
109 G4ParticleChangeForGamma* fParticleChange;
110 G4eplusTo3GammaOKVIModel* f3GModel;
111
112 G4double fDeltaMin; // fixed minimal relative limit
113 G4double fDelta; // running limit - function of energy
114 G4double fGammaTh; // 3-gamma annihilation low-energy limit
115
116 static G4PhysicsVector* fCrossSection;
117 static G4PhysicsVector* f3GProbability;
118 };
119
120 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
121
122 #endif
123