PrimaryGeneratorAction.cc

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// $Id: PrimaryGeneratorAction.cc 73024 2013-08-15 09:11:40Z gcosmo $
//
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#include "PrimaryGeneratorAction.hh"

#include "G4Event.hh"
#include "G4ParticleGun.hh"
#include "G4ParticleTable.hh"
#include "G4ParticleDefinition.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "Randomize.hh"
#include "DetectorConstruction.hh"
#include "G4RandomDirection.hh"
#include "G4RunManager.hh"
#include "G4StateManager.hh"

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PrimaryGeneratorAction::PrimaryGeneratorAction()
:G4VUserPrimaryGeneratorAction(), G4VStateDependent(),
 fParticleGun(0),
 fDetector(0)
{
  fDetector =
      dynamic_cast<const DetectorConstruction*>(G4RunManager::GetRunManager()
          ->GetUserDetectorConstruction());
}

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PrimaryGeneratorAction::~PrimaryGeneratorAction()
{
  G4StateManager::GetStateManager()->DeregisterDependent(this);
  if(fParticleGun) delete fParticleGun;
}

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void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
{    
  G4double radius = fDetector->GetAbsorRadius();

  G4double rx=1*m;
  G4double ry=1*m;
  G4double rz=1*m;

  do
  {
    rx = (2*G4UniformRand()-1)*radius;
    ry = (2*G4UniformRand()-1)*radius;
    rz = (2*G4UniformRand()-1)*radius;

  } while (std::sqrt(rx*rx+ry*ry+rz*rz)>radius) ;

  fParticleGun->SetParticlePosition(G4ThreeVector(rx,ry,rz));
  fParticleGun->SetParticleMomentumDirection(G4RandomDirection());
  fParticleGun->GeneratePrimaryVertex(anEvent);
}

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G4bool PrimaryGeneratorAction::Notify(G4ApplicationState requestedState)
{
  if(requestedState == G4State_Idle)
  {
    if(fParticleGun != 0) return true;

    fParticleGun  = new G4ParticleGun(1);

    // Define default primary
    G4ParticleDefinition* particle
             = G4ParticleTable::GetParticleTable()->FindParticle("e-");
    fParticleGun->SetParticleDefinition(particle);
    fParticleGun->SetParticleEnergy(300*eV);
    fParticleGun->SetParticlePosition(G4ThreeVector());
    fParticleGun->SetParticleMomentumDirection(G4ThreeVector(1,0,0));
  }

  return true;
}