electronScattering/src/PrimaryGeneratorAction.cc

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0026 /// \file medical/electronScattering/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 "G4ParticleTable.hh"
0041 #include "G4SystemOfUnits.hh"
0042 #include "Randomize.hh"
0043
0044 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0045
0046 PrimaryGeneratorAction::PrimaryGeneratorAction(DetectorConstruction* DC)
0047   : fParticleGun(0), fDetector(DC), fGunMessenger(0)
0048 {
0049   fParticleGun = new G4ParticleGun(1);
0050
0051   G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
0052   G4ParticleDefinition* particle = particleTable->FindParticle("e-");
0053   fParticleGun->SetParticleDefinition(particle);
0054   fParticleGun->SetParticleEnergy(20. * MeV);
0055   fZ0 = -0.5 * (fDetector->GetThicknessWorld());
0056   fParticleGun->SetParticlePosition(G4ThreeVector(0 * cm, 0 * cm, fZ0));
0057   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0., 0., 1.));
0058
0059   G4double radiusWorld = fDetector->GetRadiusWorld();
0060   fR2World = radiusWorld * radiusWorld;
0061   fRndmBeam = 420 * um;
0062
0063   // create a messenger for this class
0064   fGunMessenger = new PrimaryGeneratorMessenger(this);
0065 }
0066
0067 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0068
0069 PrimaryGeneratorAction::~PrimaryGeneratorAction()
0070 {
0071   delete fParticleGun;
0072   delete fGunMessenger;
0073 }
0074
0075 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0076
0077 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
0078 {
0079   // this function is called at the begining of event
0080   //
0081   // randomize beam, if requested.
0082   if (fRndmBeam > 0.) {
0083     G4double s_proj = fRndmBeam / std::sqrt(2.);
0084     G4double x0, y0;
0085     do {
0086       x0 = G4RandGauss::shoot(0., s_proj);
0087       y0 = G4RandGauss::shoot(0., s_proj);
0088     } while ((x0 * x0 + y0 * y0) > fR2World);
0089     fParticleGun->SetParticlePosition(G4ThreeVector(x0, y0, fZ0));
0090   }
0091
0092   fParticleGun->GeneratePrimaryVertex(anEvent);
0093 }
0094
0095 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......