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25 //
26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class header file
30 //
31 //
32 // File name: G4eeToPGammaModel
33 //
34 // Author: Vladimir Ivanchenko
35 //
36 // Creation date: 25.10.2003
37 //
38 // Modifications:
39 //
40 //
41 // -------------------------------------------------------------------
42 //
43
44
45 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
46 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
47
48 #include "G4eeToPGammaModel.hh"
49 #include "Randomize.hh"
50 #include "G4PhysicalConstants.hh"
51 #include "G4SystemOfUnits.hh"
52 #include "G4PionZero.hh"
53 #include "G4Eta.hh"
54 #include "G4Gamma.hh"
55 #include "G4DynamicParticle.hh"
56 #include "G4PhysicsVector.hh"
57 #include "G4PhysicsLinearVector.hh"
58 #include "G4eeCrossSections.hh"
59
60 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
61
62 using namespace std;
63
64 G4eeToPGammaModel::G4eeToPGammaModel(G4eeCrossSections* cr,
65 const G4String& npart,
66 G4double maxkinEnergy,
67 G4double binWidth)
68 : G4Vee2hadrons(cr,
69 npart=="pi0" ? 782.62*MeV:1019.46*MeV,
70 maxkinEnergy,
71 binWidth)
72 {
73 G4cout << "####G4eeToPGammaModel & particle:" << npart
74 << "####" << G4endl;
75
76 pi0 = G4PionZero::PionZero();
77 if(npart == "pi0") {
78 massR = 782.62*MeV;
79 particle = pi0;
80 } else {
81 massR = 1019.46*MeV;
82 particle = G4Eta::Eta();
83 }
84 massP = particle->GetPDGMass();
85 }
86
87 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
88
89 G4eeToPGammaModel::~G4eeToPGammaModel()
90 {}
91
92 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
93
94 G4double G4eeToPGammaModel::PeakEnergy() const
95 {
96 return massR;
97 }
98
99 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
100
101 G4double G4eeToPGammaModel::ComputeCrossSection(G4double e) const
102 {
103 G4double xs;
104 if(particle == pi0) xs = cross->CrossSectionPi0G(e);
105 else xs = cross->CrossSectionEtaG(e);
106 return xs;
107 }
108
109 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
110
111 void G4eeToPGammaModel::SampleSecondaries(std::vector<G4DynamicParticle*>* newp,
112 G4double e, const G4ThreeVector& direction)
113 {
114 G4double egam = 0.5*e*(1.0 - massP*massP/(massR*massR));
115 G4double tkin = e - egam - massP;
116 if(tkin < 0.0) tkin = 0.0;
117 G4double cost;
118 do {
119 cost = 2.0*G4UniformRand() - 1.0;
120 // Loop checking, 07-Aug-2015, Vladimir Ivanchenko
121 } while( 2.0*G4UniformRand() > 1.0 + cost*cost );
122
123 G4double sint = sqrt(1.0 - cost*cost);
124 G4double phi = twopi * G4UniformRand();
125
126 G4ThreeVector dir(sint*cos(phi),sint*sin(phi), cost);
127 dir.rotateUz(direction);
128
129 // create G4DynamicParticle objects
130 G4DynamicParticle* p1 =
131 new G4DynamicParticle(particle,dir,tkin);
132 G4DynamicParticle* p2 =
133 new G4DynamicParticle(G4Gamma::Gamma(),-dir,egam);
134 newp->push_back(p1);
135 newp->push_back(p2);
136 }
137
138 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
139
140