TestEm4/src/PrimaryGeneratorAction.cc

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0026 /// \file electromagnetic/TestEm4/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 "G4Event.hh"
0036 #include "G4ParticleDefinition.hh"
0037 #include "G4ParticleGun.hh"
0038 #include "G4ParticleTable.hh"
0039 #include "G4PhysicalConstants.hh"
0040 #include "G4SystemOfUnits.hh"
0041 #include "Randomize.hh"
0042
0043 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0044
0045 PrimaryGeneratorAction::PrimaryGeneratorAction()
0046 {
0047   G4int n_particle = 1;
0048   fParticleGun = new G4ParticleGun(n_particle);
0049
0050   // default particle kinematic
0051
0052   G4ParticleDefinition* particle = G4ParticleTable::GetParticleTable()->FindParticle("gamma");
0053   fParticleGun->SetParticleDefinition(particle);
0054   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(1., 0., 0.));
0055   fParticleGun->SetParticleEnergy(9 * MeV);
0056   fParticleGun->SetParticlePosition(G4ThreeVector(0. * cm, 0. * cm, 0. * cm));
0057 }
0058
0059 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0060
0061 PrimaryGeneratorAction::~PrimaryGeneratorAction()
0062 {
0063   delete fParticleGun;
0064 }
0065
0066 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0067
0068 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
0069 {
0070   // this function is called at the begining of event
0071   //
0072   // distribution uniform in solid angle
0073   //
0074   G4double cosTheta = 2 * G4UniformRand() - 1., phi = twopi * G4UniformRand();
0075   G4double sinTheta = std::sqrt(1. - cosTheta * cosTheta);
0076   G4double ux = sinTheta * std::cos(phi), uy = sinTheta * std::sin(phi), uz = cosTheta;
0077
0078   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(ux, uy, uz));
0079
0080   fParticleGun->GeneratePrimaryVertex(anEvent);
0081 }
0082
0083 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......