source: trunk/source/processes/electromagnetic/highenergy/src/G4eeToPGammaModel.cc @ 1315

Last change on this file since 1315 was 1228, checked in by garnier, 14 years ago

update geant4.9.3 tag
File size: 4.9 KB
Line 
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25//
26// $Id: G4eeToPGammaModel.cc,v 1.2 2009/02/20 16:38:33 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-03 $
28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class header file
32//
33//
34// File name:     G4eeToPGammaModel
35//
36// Author:        Vladimir Ivanchenko
37//
38// Creation date: 25.10.2003
39//
40// Modifications:
41//
42//
43// -------------------------------------------------------------------
44//
45
46
47//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
48//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
49
50#include "G4eeToPGammaModel.hh"
51#include "Randomize.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
62using namespace std;
63
64G4eeToPGammaModel::G4eeToPGammaModel(G4eeCrossSections* cr, const G4String& npart):
65  cross(cr)
66{
67  pi0 = G4PionZero::PionZero();
68  if(npart == "pi0") {
69    massR = 782.62*MeV;
70    particle = pi0;
71  } else {
72    massR = 1019.46*MeV;
73    particle = G4Eta::Eta();
74  }
75  massP = particle->GetPDGMass();
76}
77
78//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
79
80G4eeToPGammaModel::~G4eeToPGammaModel()
81{}
82
83//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
84
85G4double G4eeToPGammaModel::ThresholdEnergy() const
86{
87  return LowEnergy();
88}
89
90//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
91
92G4double G4eeToPGammaModel::PeakEnergy() const
93{
94  return massR;
95}
96
97//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
98
99G4double G4eeToPGammaModel::ComputeCrossSection(G4double e) const
100{
101  G4double ee = std::min(HighEnergy(),e);
102  G4double xs;
103  if(particle == pi0) xs = cross->CrossSectionPi0G(ee);
104  else                xs = cross->CrossSectionEtaG(ee);
105  return xs;
106}
107
108//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
109
110G4PhysicsVector* G4eeToPGammaModel::PhysicsVector(G4double emin, 
111                                                  G4double emax) const
112{
113  G4double tmin = std::max(emin, ThresholdEnergy());
114  G4double tmax = std::max(tmin, emax);
115  G4int nbins = (G4int)((tmax - tmin)/(5.*MeV));
116  G4PhysicsVector* v = new G4PhysicsLinearVector(emin,emax,nbins);
117  v->SetSpline(true);
118  return v;
119}
120
121//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
122
123void G4eeToPGammaModel::SampleSecondaries(std::vector<G4DynamicParticle*>* newp,
124            G4double e, const G4ThreeVector& direction)
125{
126  G4double egam = 0.5*e*(1.0 - massP*massP/(massR*massR));
127  G4double tkin = e - egam - massP;
128  if(tkin < 0.0) tkin = 0.0;
129  G4double cost;
130  do {
131    cost = 2.0*G4UniformRand() - 1.0;
132  } while( 2.0*G4UniformRand() > 1.0 + cost*cost );
133
134  G4double sint = sqrt(1.0 - cost*cost);
135  G4double phi  = twopi * G4UniformRand();
136
137  G4ThreeVector dir(sint*cos(phi),sint*sin(phi), cost);
138  dir.rotateUz(direction);
139
140  // create G4DynamicParticle objects
141  G4DynamicParticle* p1 = 
142     new G4DynamicParticle(particle,dir,tkin);
143  G4DynamicParticle* p2 = 
144     new G4DynamicParticle(G4Gamma::Gamma(),-dir,egam);
145  newp->push_back(p1);
146  newp->push_back(p2);
147}
148
149//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
150
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