RE02PrimaryGeneratorAction.cc

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#include "RE02PrimaryGeneratorAction.hh"

#include "G4Event.hh"
#include "G4ParticleGun.hh"
#include "G4ParticleTable.hh"
#include "G4ParticleDefinition.hh"
#include "Randomize.hh"
#include "globals.hh"
#include "G4SystemOfUnits.hh"    

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
//
RE02PrimaryGeneratorAction::RE02PrimaryGeneratorAction()
 : G4VUserPrimaryGeneratorAction(),
   fParticleGun(0)
{
  G4int n_particle = 1;
  fParticleGun = new G4ParticleGun(n_particle);

// default particle
  G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
  G4ParticleDefinition* particle = particleTable->FindParticle("proton");
  fParticleGun->SetParticleDefinition(particle);
  fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0.0,0.0,1.));
  fParticleGun->SetParticleEnergy(150.0*MeV);
//
// default beam position
  G4double position = -200./2.*cm;
//
// Initial beam spot size in sigma.; This is not a part of ParticleGun.
  fSigmaPosition = 10.* mm;

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
//
  fParticleGun->SetParticlePosition(G4ThreeVector(0.*cm, 0.*cm, position));
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
//
RE02PrimaryGeneratorAction::~RE02PrimaryGeneratorAction()
{
  delete fParticleGun;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
//
void RE02PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
{ 

  G4ThreeVector position = fParticleGun->GetParticlePosition();
  G4double dx = (G4UniformRand()-0.5)*fSigmaPosition;
  G4double dy = (G4UniformRand()-0.5)*fSigmaPosition;
  position.setX(dx);
  position.setY(dy);
  fParticleGun->SetParticlePosition(position);
  fParticleGun->GeneratePrimaryVertex(anEvent);
}