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G4eeToPGammaModel.cc
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26 // $Id: G4eeToPGammaModel.cc 91869 2015-08-07 15:21:02Z gcosmo $
27 //
28 // -------------------------------------------------------------------
29 //
30 // GEANT4 Class header file
31 //
32 //
33 // File name: G4eeToPGammaModel
34 //
35 // Author: Vladimir Ivanchenko
36 //
37 // Creation date: 25.10.2003
38 //
39 // Modifications:
40 //
41 //
42 // -------------------------------------------------------------------
43 //
44 
45 
46 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
47 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
48 
49 #include "G4eeToPGammaModel.hh"
50 #include "Randomize.hh"
51 #include "G4PhysicalConstants.hh"
52 #include "G4SystemOfUnits.hh"
53 #include "G4PionZero.hh"
54 #include "G4Eta.hh"
55 #include "G4Gamma.hh"
56 #include "G4DynamicParticle.hh"
57 #include "G4PhysicsVector.hh"
58 #include "G4PhysicsLinearVector.hh"
59 #include "G4eeCrossSections.hh"
60 
61 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
62 
63 using namespace std;
64 
66  const G4String& npart,
67  G4double maxkinEnergy,
68  G4double binWidth)
69 : G4Vee2hadrons(cr,
70  npart=="pi0" ? 782.62*MeV:1019.46*MeV,
71  maxkinEnergy,
72  binWidth)
73 {
74  G4cout << "####G4eeToPGammaModel & particle:" << npart
75  << "####" << G4endl;
76 
77  pi0 = G4PionZero::PionZero();
78  if(npart == "pi0") {
79  massR = 782.62*MeV;
80  particle = pi0;
81  } else {
82  massR = 1019.46*MeV;
83  particle = G4Eta::Eta();
84  }
85  massP = particle->GetPDGMass();
86 
87 }
88 
89 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
90 
92 {}
93 
94 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
95 
97 {
98  return massR;
99 }
100 
101 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
102 
104 {
105  G4double xs;
106  if(particle == pi0) xs = cross->CrossSectionPi0G(e);
107  else xs = cross->CrossSectionEtaG(e);
108  return xs;
109 }
110 
111 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
112 
113 void G4eeToPGammaModel::SampleSecondaries(std::vector<G4DynamicParticle*>* newp,
114  G4double e, const G4ThreeVector& direction)
115 {
116  G4double egam = 0.5*e*(1.0 - massP*massP/(massR*massR));
117  G4double tkin = e - egam - massP;
118  if(tkin < 0.0) tkin = 0.0;
119  G4double cost;
120  do {
121  cost = 2.0*G4UniformRand() - 1.0;
122  // Loop checking, 07-Aug-2015, Vladimir Ivanchenko
123  } while( 2.0*G4UniformRand() > 1.0 + cost*cost );
124 
125  G4double sint = sqrt(1.0 - cost*cost);
126  G4double phi = twopi * G4UniformRand();
127 
128  G4ThreeVector dir(sint*cos(phi),sint*sin(phi), cost);
129  dir.rotateUz(direction);
130 
131  // create G4DynamicParticle objects
132  G4DynamicParticle* p1 =
133  new G4DynamicParticle(particle,dir,tkin);
134  G4DynamicParticle* p2 =
135  new G4DynamicParticle(G4Gamma::Gamma(),-dir,egam);
136  newp->push_back(p1);
137  newp->push_back(p2);
138 }
139 
140 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
141 
virtual G4double PeakEnergy() const override
virtual ~G4eeToPGammaModel()
virtual void SampleSecondaries(std::vector< G4DynamicParticle * > *, G4double, const G4ThreeVector &) override
static G4Eta * Eta()
Definition: G4Eta.cc:109
static constexpr double twopi
Definition: G4SIunits.hh:76
G4double CrossSectionEtaG(G4double)
G4double CrossSectionPi0G(G4double)
#define G4UniformRand()
Definition: Randomize.hh:97
G4GLOB_DLL std::ostream G4cout
Hep3Vector & rotateUz(const Hep3Vector &)
Definition: ThreeVector.cc:38
static G4Gamma * Gamma()
Definition: G4Gamma.cc:86
static G4PionZero * PionZero()
Definition: G4PionZero.cc:108
virtual G4double ComputeCrossSection(G4double) const override
G4double GetPDGMass() const
G4eeCrossSections * cross
#define G4endl
Definition: G4ios.hh:61
static constexpr double MeV
Definition: G4SIunits.hh:214
double G4double
Definition: G4Types.hh:76
G4eeToPGammaModel(G4eeCrossSections *, const G4String &, G4double, G4double)