B4a/src/PrimaryGeneratorAction.cc

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0025 //
0026 /// \file PrimaryGeneratorAction.cc
0027 /// \brief Implementation of the B4::PrimaryGeneratorAction class
0028
0029 #include "PrimaryGeneratorAction.hh"
0030
0031 #include "G4Box.hh"
0032 #include "G4LogicalVolume.hh"
0033 #include "G4LogicalVolumeStore.hh"
0034 #include "G4ParticleGun.hh"
0035 #include "G4ParticleTable.hh"
0036 #include "G4SystemOfUnits.hh"
0037 #include "globals.hh"
0038
0039 namespace B4
0040 {
0041
0042 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0043
0044 PrimaryGeneratorAction::PrimaryGeneratorAction()
0045 {
0046   G4int nofParticles = 1;
0047   fParticleGun = new G4ParticleGun(nofParticles);
0048
0049   // default particle kinematic
0050   //
0051   auto particleDefinition = G4ParticleTable::GetParticleTable()->FindParticle("e-");
0052   fParticleGun->SetParticleDefinition(particleDefinition);
0053   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0., 0., 1.));
0054   fParticleGun->SetParticleEnergy(300. * MeV);
0055 }
0056
0057 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0058
0059 PrimaryGeneratorAction::~PrimaryGeneratorAction()
0060 {
0061   delete fParticleGun;
0062 }
0063
0064 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0065
0066 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* event)
0067 {
0068   // This function is called at the begining of event
0069
0070   // In order to avoid dependence of PrimaryGeneratorAction
0071   // on DetectorConstruction class we get world volume
0072   // from G4LogicalVolumeStore
0073   //
0074   G4double worldZHalfLength = 0.;
0075   auto worldLV = G4LogicalVolumeStore::GetInstance()->GetVolume("World");
0076
0077   // Check that the world volume has box shape
0078   G4Box* worldBox = nullptr;
0079   if (worldLV) {
0080     worldBox = dynamic_cast<G4Box*>(worldLV->GetSolid());
0081   }
0082
0083   if (worldBox) {
0084     worldZHalfLength = worldBox->GetZHalfLength();
0085   }
0086   else {
0087     G4ExceptionDescription msg;
0088     msg << "World volume of box shape not found." << G4endl;
0089     msg << "Perhaps you have changed geometry." << G4endl;
0090     msg << "The gun will be place in the center.";
0091     G4Exception("PrimaryGeneratorAction::GeneratePrimaries()", "MyCode0002", JustWarning, msg);
0092   }
0093
0094   // Set gun position
0095   fParticleGun->SetParticlePosition(G4ThreeVector(0., 0., -worldZHalfLength));
0096
0097   fParticleGun->GeneratePrimaryVertex(event);
0098 }
0099
0100 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0101
0102 }  // namespace B4