NeutronSource/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 "DetectorConstruction.hh"
0032
0033 #include "G4Event.hh"
0034 #include "G4Geantino.hh"
0035 #include "G4IonTable.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(DetectorConstruction* det) : fDetector(det)
0045 {
0046   G4int n_particle = 1;
0047   fParticleGun = new G4ParticleGun(n_particle);
0048
0049   fParticleGun->SetParticleEnergy(0 * eV);
0050   fParticleGun->SetParticlePosition(G4ThreeVector(0., 0., 0.));
0051   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0., 0., 1.));
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   // particle type
0066   if (fParticleGun->GetParticleDefinition() == G4Geantino::Geantino()) {
0067     G4int Z = 95, A = 241;
0068     G4double ionCharge = 0. * eplus;
0069     G4double excitEnergy = 0. * keV;
0070
0071     G4ParticleDefinition* ion = G4IonTable::GetIonTable()->GetIon(Z, A, excitEnergy);
0072     fParticleGun->SetParticleDefinition(ion);
0073     fParticleGun->SetParticleCharge(ionCharge);
0074   }
0075
0076   // vertex position uniform within the absorber
0077   //
0078   G4double Rmax = fDetector->GetAbsorRadius();
0079   G4double Rmax2 = Rmax * Rmax;
0080   G4double R2 = G4UniformRand() * Rmax2;
0081   G4double R = std::sqrt(R2);
0082
0083   G4double phi = twopi * G4UniformRand();
0084   G4double ux = R * std::cos(phi), uy = R * std::sin(phi);
0085   G4double uz = (fDetector->GetAbsorLength()) * (G4UniformRand() - 0.5);
0086
0087   fParticleGun->SetParticlePosition(G4ThreeVector(ux, uy, uz));
0088
0089   // distribution uniform in solid angle
0090   //
0091   G4double cosTheta = 2 * G4UniformRand() - 1.;
0092   G4double sinTheta = std::sqrt(1. - cosTheta * cosTheta);
0093   phi = twopi * G4UniformRand();
0094   G4double vx = sinTheta * std::cos(phi), vy = sinTheta * std::sin(phi), vz = cosTheta;
0095
0096   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(vx, vy, vz));
0097
0098   fParticleGun->GeneratePrimaryVertex(anEvent);
0099 }
0100
0101 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......