fanoCavity/src/PrimaryGeneratorAction.cc

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0026 /// \file medical/fanoCavity/src/PrimaryGeneratorAction.cc
0027 /// \brief Implementation of the PrimaryGeneratorAction class
0028 //
0029 //
0030 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0031 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0032
0033 #include "PrimaryGeneratorAction.hh"
0034
0035 #include "DetectorConstruction.hh"
0036 #include "PrimaryGeneratorMessenger.hh"
0037
0038 #include "G4Event.hh"
0039 #include "G4ParticleDefinition.hh"
0040 #include "G4ParticleGun.hh"
0041 #include "G4ParticleTable.hh"
0042 #include "G4PhysicalConstants.hh"
0043 #include "G4SystemOfUnits.hh"
0044 #include "Randomize.hh"
0045
0046 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0047
0048 PrimaryGeneratorAction::PrimaryGeneratorAction(DetectorConstruction* det)
0049   : fParticleGun(0), fDetector(det), fGunMessenger(0)
0050 {
0051   fParticleGun = new G4ParticleGun(1);
0052   G4ParticleDefinition* particle = G4ParticleTable::GetParticleTable()->FindParticle("gamma");
0053   fParticleGun->SetParticleDefinition(particle);
0054   fParticleGun->SetParticleEnergy(1.25 * MeV);
0055   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0., 0., 1.));
0056
0057   fRBeam = 1.;
0058
0059   // create a messenger for this class
0060   fGunMessenger = new PrimaryGeneratorMessenger(this);
0061 }
0062
0063 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0064
0065 PrimaryGeneratorAction::~PrimaryGeneratorAction()
0066 {
0067   delete fParticleGun;
0068   delete fGunMessenger;
0069 }
0070
0071 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0072
0073 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
0074 {
0075   // this function is called at the begining of event
0076   //
0077   G4double z0 = -0.5 * (fDetector->GetTotalThickness());
0078   G4double x0 = 0. * cm, y0 = 0. * cm;
0079
0080   // beam width
0081   //
0082   if (fRBeam > 0.) {
0083     G4double beam = fRBeam * (fDetector->GetWallRadius());
0084     G4double r = beam * std::sqrt(G4UniformRand());
0085     G4double theta = twopi * G4UniformRand();
0086     x0 = r * std::cos(theta);
0087     y0 = r * std::sin(theta);
0088   }
0089   fParticleGun->SetParticlePosition(G4ThreeVector(x0, y0, z0));
0090   fParticleGun->GeneratePrimaryVertex(anEvent);
0091 }
0092
0093 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......