B4a/src/PrimaryGeneratorAction.cc

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0026 //
0027 /// \file B4/B4a/src/PrimaryGeneratorAction.cc
0028 /// \brief Implementation of the B4::PrimaryGeneratorAction class
0029
0030 #include "PrimaryGeneratorAction.hh"
0031
0032 #include "G4Box.hh"
0033 #include "G4LogicalVolume.hh"
0034 #include "G4LogicalVolumeStore.hh"
0035 #include "G4ParticleGun.hh"
0036 #include "G4ParticleTable.hh"
0037 #include "G4SystemOfUnits.hh"
0038 #include "globals.hh"
0039
0040 namespace B4
0041 {
0042
0043 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0044
0045 PrimaryGeneratorAction::PrimaryGeneratorAction()
0046 {
0047   G4int nofParticles = 1;
0048   fParticleGun = new G4ParticleGun(nofParticles);
0049
0050   // default particle kinematic
0051   //
0052   auto particleDefinition = G4ParticleTable::GetParticleTable()->FindParticle("e-");
0053   fParticleGun->SetParticleDefinition(particleDefinition);
0054   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0., 0., 1.));
0055   fParticleGun->SetParticleEnergy(300. * MeV);
0056 }
0057
0058 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0059
0060 PrimaryGeneratorAction::~PrimaryGeneratorAction()
0061 {
0062   delete fParticleGun;
0063 }
0064
0065 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0066
0067 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* event)
0068 {
0069   // This function is called at the begining of event
0070
0071   // In order to avoid dependence of PrimaryGeneratorAction
0072   // on DetectorConstruction class we get world volume
0073   // from G4LogicalVolumeStore
0074   //
0075   G4double worldZHalfLength = 0.;
0076   auto worldLV = G4LogicalVolumeStore::GetInstance()->GetVolume("World");
0077
0078   // Check that the world volume has box shape
0079   G4Box* worldBox = nullptr;
0080   if (worldLV) {
0081     worldBox = dynamic_cast<G4Box*>(worldLV->GetSolid());
0082   }
0083
0084   if (worldBox) {
0085     worldZHalfLength = worldBox->GetZHalfLength();
0086   }
0087   else {
0088     G4ExceptionDescription msg;
0089     msg << "World volume of box shape not found." << G4endl;
0090     msg << "Perhaps you have changed geometry." << G4endl;
0091     msg << "The gun will be place in the center.";
0092     G4Exception("PrimaryGeneratorAction::GeneratePrimaries()", "MyCode0002", JustWarning, msg);
0093   }
0094
0095   // Set gun position
0096   fParticleGun->SetParticlePosition(G4ThreeVector(0., 0., -worldZHalfLength));
0097
0098   fParticleGun->GeneratePrimaryVertex(event);
0099 }
0100
0101 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0102
0103 }  // namespace B4