Hadr04/src/PrimaryGeneratorAction.cc

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0025 //
0026 /// \file 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 "G4Event.hh"
0036 #include "G4ParticleDefinition.hh"
0037 #include "G4ParticleTable.hh"
0038 #include "G4PhysicalConstants.hh"
0039 #include "G4SystemOfUnits.hh"
0040 #include "Randomize.hh"
0041
0042 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0043
0044 PrimaryGeneratorAction::PrimaryGeneratorAction()
0045 {
0046   G4int n_particle = 1;
0047   fParticleGun = new G4ParticleGun(n_particle);
0048
0049   // default particle kinematic
0050
0051   G4ParticleDefinition* particle = G4ParticleTable::GetParticleTable()->FindParticle("neutron");
0052   fParticleGun->SetParticleDefinition(particle);
0053   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(1., 0., 0.));
0054   fParticleGun->SetParticleEnergy(2 * MeV);
0055   fParticleGun->SetParticlePosition(G4ThreeVector(0. * cm, 0. * cm, 0. * cm));
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* anEvent)
0068 {
0069   // this function is called at the begining of event
0070   //
0071   // distribution uniform in solid angle
0072   //
0073   G4double cosTheta = 2 * G4UniformRand() - 1., phi = twopi * G4UniformRand();
0074   G4double sinTheta = std::sqrt(1. - cosTheta * cosTheta);
0075   G4double ux = sinTheta * std::cos(phi), uy = sinTheta * std::sin(phi), uz = cosTheta;
0076
0077   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(ux, uy, uz));
0078
0079   fParticleGun->GeneratePrimaryVertex(anEvent);
0080 }
0081
0082 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......