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25 //
26 //
27 /// \file B2/B2b/src/PrimaryGeneratorAction.cc
28 /// \brief Implementation of the B2::PrimaryGeneratorAction class
29
30 #include "PrimaryGeneratorAction.hh"
31
32 #include "G4Box.hh"
33 #include "G4LogicalVolume.hh"
34 #include "G4LogicalVolumeStore.hh"
35 #include "G4ParticleGun.hh"
36 #include "G4ParticleTable.hh"
37 #include "G4SystemOfUnits.hh"
38 #include "globals.hh"
39
40 namespace B2
41 {
42
43 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
44
45 PrimaryGeneratorAction::PrimaryGeneratorAction()
46 {
47 G4int nofParticles = 1;
48 fParticleGun = new G4ParticleGun(nofParticles);
49
50 // default particle kinematic
51
52 G4ParticleDefinition* particleDefinition =
53 G4ParticleTable::GetParticleTable()->FindParticle("proton");
54
55 fParticleGun->SetParticleDefinition(particleDefinition);
56 fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0., 0., 1.));
57 fParticleGun->SetParticleEnergy(3.0 * GeV);
58 }
59
60 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
61
62 PrimaryGeneratorAction::~PrimaryGeneratorAction()
63 {
64 delete fParticleGun;
65 }
66
67 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
68
69 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* event)
70 {
71 // This function is called at the begining of event
72
73 // In order to avoid dependence of PrimaryGeneratorAction
74 // on DetectorConstruction class we get world volume
75 // from G4LogicalVolumeStore.
76
77 G4double worldZHalfLength = 0;
78 G4LogicalVolume* worldLV = G4LogicalVolumeStore::GetInstance()->GetVolume("World");
79 G4Box* worldBox = nullptr;
80 if (worldLV) worldBox = dynamic_cast<G4Box*>(worldLV->GetSolid());
81 if (worldBox)
82 worldZHalfLength = worldBox->GetZHalfLength();
83 else {
84 G4cerr << "World volume of box not found." << G4endl;
85 G4cerr << "Perhaps you have changed geometry." << G4endl;
86 G4cerr << "The gun will be place in the center." << G4endl;
87 }
88
89 // Starting a primary particle close to the world boundary.
90 //
91 fParticleGun->SetParticlePosition(G4ThreeVector(0., 0., -worldZHalfLength + 1 * um));
92
93 fParticleGun->GeneratePrimaryVertex(event);
94 }
95
96 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
97
98 } // namespace B2
99