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PrimaryGeneratorAction.cc
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25 //
26 // This example is provided by the Geant4-DNA collaboration
27 // Any report or published results obtained using the Geant4-DNA software
28 // shall cite the following Geant4-DNA collaboration publication:
29 // Med. Phys. 37 (2010) 4692-4708
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32 // If you use this example, please cite the following publication:
33 // Rad. Prot. Dos. 133 (2009) 2-11
34 
35 #include "G4SystemOfUnits.hh"
36 #include "G4Event.hh"
37 #include "G4ParticleTable.hh"
38 #include "Randomize.hh"
39 
40 #include "PrimaryGeneratorAction.hh"
41 
42 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
43 
44 PrimaryGeneratorAction::PrimaryGeneratorAction()
45 {
46  fParticleGun = new G4ParticleGun(1);
47 }
48 
49 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
50 
51 PrimaryGeneratorAction::~PrimaryGeneratorAction()
52 {
53  delete fParticleGun;
54 }
55 
56 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
57 
58 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
59 {
60  G4int numEvent;
61  numEvent=anEvent->GetEventID()+1;
62  G4double x0,y0,z0,theta,phi,xMom0,yMom0,zMom0,e0;
63 
64  // INITIAL BEAM POSITION
65 
66  z0=-10000*mm;
67  x0=10*mm;
68  y0=10*mm;
69 
70  G4double sizeMax = 0.5*micrometer; // INITIAL BEAM POSITION UNIFORMLY SPREAD ON A DISK
71  while (! (std::sqrt(x0*x0+y0*y0)<= sizeMax) )
72  {
73  x0 = CLHEP::RandFlat::shoot(-sizeMax,sizeMax);
74  y0 = CLHEP::RandFlat::shoot(-sizeMax,sizeMax);
75  }
76 
77  // INITIAL BEAM ENERGY
78 
79  e0= G4RandGauss::shoot(3*MeV,5.0955e-5*MeV); // AIFIRA ENERGY RESOLUTION
80 
81  // INITIAL BEAM DIVERGENCE
82 
83  do {
84  theta=std::acos(1-G4UniformRand()*(1.0-std::cos(1.1e-6)))*rad;
85  }
86  while(theta>1.1e-6*rad);
87 
88  phi=CLHEP::twopi*G4UniformRand()*rad;
89 
90  xMom0=std::sin(theta)*std::cos(phi);
91  yMom0=std::sin(theta)*std::sin(phi);
92  zMom0=std::cos(theta);
93 
94  // VERBOSE
95 
96  G4cout
97  << "-> Event # " << numEvent
98  << " generated "
99  << G4endl;
100 
101 /*
102  G4cout
103  << "-> Event # " << numEvent
104  << " : THETA from Z axis (mrad) = " << theta*1000
105  << " -- PHI (deg) = " << phi*180/CLHEP::pi
106  << " -- x0 (um) = " << x0/micrometer
107  << " -- y0 (um) = " << y0/micrometer
108  << " -- z0 (m) = " << z0/m
109  << " -- e0 (MeV) = " << e0/MeV
110  << G4endl;
111 */
112 
113  fParticleGun->SetParticleEnergy(e0);
114 
115  fParticleGun->SetParticleMomentumDirection(G4ThreeVector(xMom0,yMom0,zMom0));
116 
117  fParticleGun->SetParticlePosition(G4ThreeVector(x0,y0,z0));
118 
119  G4ParticleDefinition* particle=
120  G4ParticleTable::GetParticleTable()->FindParticle("alpha");
121 
122  fParticleGun->SetParticleDefinition(particle);
123 
124  fParticleGun->GeneratePrimaryVertex(anEvent);
125 
126 }