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25 //
26 //
27 // -------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4ModifiedMephi
33 //
34 // Author: V. Ivanchenko
35 //
36 // Creation date: 27 October 2020
37 //
38 // Modifications:
39 //
40 //
41 // -------------------------------------------
42 //
43
44 #include "G4ModifiedMephi.hh"
45 #include "Randomize.hh"
46 #include "G4Log.hh"
47 #include <CLHEP/Units/PhysicalConstants.h>
48
49 //....oooOO0OOooo........oooOO0OOooo........oo
50
51 G4ModifiedMephi::G4ModifiedMephi(const G4Strin
52 : G4VEmAngularDistribution("ModifiedMephi")
53 {}
54
55 //....oooOO0OOooo........oooOO0OOooo........oo
56
57 G4ModifiedMephi::~G4ModifiedMephi()
58 {}
59
60 //....oooOO0OOooo........oooOO0OOooo........oo
61
62 G4ThreeVector&
63 G4ModifiedMephi::SampleDirection(const G4Dynam
64 G4double gEne
65 const G4Mater
66 {
67 // Sample gamma angle (Z - axis along the pa
68 G4double cost = SampleCosTheta(dp->GetKineti
69 dp->GetDefini
70 G4double sint = std::sqrt((1.0 - cost)*(1.0
71 G4double phi = CLHEP::twopi*G4UniformRand()
72
73 fLocalDirection.set(sint*std::cos(phi), sint
74 fLocalDirection.rotateUz(dp->GetMomentumDire
75
76 return fLocalDirection;
77 }
78
79 //....oooOO0OOooo........oooOO0OOooo........oo
80
81 G4double G4ModifiedMephi::SampleCosTheta(G4dou
82 G4dou
83 G4dou
84 {
85 G4double gam = 1.0 + primKinEnergy/mass;
86 G4double rmax = gam*CLHEP::halfpi*std::min(1
87 G4double rmax2= rmax*rmax;
88 G4double x = G4UniformRand()*rmax2/(1.0 + rm
89
90 return std::cos(std::sqrt(x/(1.0 - x))/gam);
91 }
92
93 //....oooOO0OOooo........oooOO0OOooo........oo
94
95 void G4ModifiedMephi::SamplePairDirections(con
96 G4double elecKinEnergy,
97 G4double posiKinEnergy,
98 G4ThreeVector& dirElectron,
99 G4ThreeVector& dirPositron,
100 G4int, const G4Material*)
101 {
102 G4double phi = CLHEP::twopi * G4UniformRand
103 G4double sinp = std::sin(phi);
104 G4double cosp = std::cos(phi);
105
106 G4double ekin = dp->GetKineticEnergy();
107 G4double etwo = elecKinEnergy + posiKinEnerg
108 G4double mass = dp->GetDefinition()->GetPDGM
109
110 G4double cost = SampleCosTheta(ekin, etwo, m
111 G4double sint = std::sqrt((1.0 - cost)*(1.0
112
113 dirElectron.set(sint*cosp, sint*sinp, cost);
114 dirElectron.rotateUz(dp->GetMomentumDirectio
115
116 cost = SampleCosTheta(ekin, etwo, mass);
117 sint = std::sqrt((1.0 - cost)*(1.0 + cost));
118
119 dirPositron.set(-sint*cosp, -sint*sinp, cost
120 dirPositron.rotateUz(dp->GetMomentumDirectio
121 }
122
123 //....oooOO0OOooo........oooOO0OOooo........oo
124
125 void G4ModifiedMephi::PrintGeneratorInformatio
126 {
127 G4cout << "\n" << G4endl;
128 G4cout << "Angular Generator is Modified Mep
129 }
130
131 //....oooOO0OOooo........oooOO0OOooo........oo
132