Hadr04/src/PrimaryGeneratorAction.cc

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0025 //
0026 /// \file PrimaryGeneratorAction.cc
0027 /// \brief Implementation of the PrimaryGeneratorAction class
0028
0029 #include "PrimaryGeneratorAction.hh"
0030
0031 #include "G4Event.hh"
0032 #include "G4ParticleDefinition.hh"
0033 #include "G4ParticleTable.hh"
0034 #include "G4PhysicalConstants.hh"
0035 #include "G4SystemOfUnits.hh"
0036 #include "Randomize.hh"
0037
0038 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0039
0040 PrimaryGeneratorAction::PrimaryGeneratorAction()
0041 {
0042   G4int n_particle = 1;
0043   fParticleGun = new G4ParticleGun(n_particle);
0044
0045   // default particle kinematic
0046
0047   G4ParticleDefinition* particle = G4ParticleTable::GetParticleTable()->FindParticle("neutron");
0048   fParticleGun->SetParticleDefinition(particle);
0049   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(1., 0., 0.));
0050   fParticleGun->SetParticleEnergy(2 * MeV);
0051   fParticleGun->SetParticlePosition(G4ThreeVector(0. * cm, 0. * cm, 0. * cm));
0052 }
0053
0054 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0055
0056 PrimaryGeneratorAction::~PrimaryGeneratorAction()
0057 {
0058   delete fParticleGun;
0059 }
0060
0061 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0062
0063 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
0064 {
0065   // this function is called at the begining of event
0066   //
0067   // distribution uniform in solid angle
0068   //
0069   G4double cosTheta = 2 * G4UniformRand() - 1., phi = twopi * G4UniformRand();
0070   G4double sinTheta = std::sqrt(1. - cosTheta * cosTheta);
0071   G4double ux = sinTheta * std::cos(phi), uy = sinTheta * std::sin(phi), uz = cosTheta;
0072
0073   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(ux, uy, uz));
0074
0075   fParticleGun->GeneratePrimaryVertex(anEvent);
0076 }
0077
0078 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......