examples/extended/medical/electronScattering/src/PrimaryGeneratorAction.cc

Go to the documentation of this file.

//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
/// \file medical/electronScattering/src/PrimaryGeneratorAction.cc
/// \brief Implementation of the PrimaryGeneratorAction class
//
// $Id: PrimaryGeneratorAction.cc 68393 2013-03-25 14:22:21Z maire $
//
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

#include "PrimaryGeneratorAction.hh"

#include "DetectorConstruction.hh"
#include "PrimaryGeneratorMessenger.hh"

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

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

PrimaryGeneratorAction::PrimaryGeneratorAction(DetectorConstruction* DC)
:fParticleGun(0), fDetector(DC), fGunMessenger(0)
{
  fParticleGun  = new G4ParticleGun(1);

  G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
  G4ParticleDefinition* particle = particleTable->FindParticle("e-");
  fParticleGun->SetParticleDefinition(particle);
  fParticleGun->SetParticleEnergy(20.*MeV);
  fZ0 = -0.5*(fDetector->GetThicknessWorld());
  fParticleGun->SetParticlePosition(G4ThreeVector(0*cm, 0*cm, fZ0));   
  fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0.,0.,1.));
  
  G4double radiusWorld = fDetector->GetRadiusWorld();
  fR2World = radiusWorld*radiusWorld; 
  fRndmBeam = 420*um;
          
  //create a messenger for this class
  fGunMessenger = new PrimaryGeneratorMessenger(this);
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

PrimaryGeneratorAction::~PrimaryGeneratorAction()
{
  delete fParticleGun;
  delete fGunMessenger;  
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
{
  //this function is called at the begining of event
  //
  //randomize beam, if requested.
  if (fRndmBeam > 0.) {
    G4double s_proj = fRndmBeam/std::sqrt(2.);
    G4double x0, y0;     
    do {
        x0 = G4RandGauss::shoot(0.,s_proj);
        y0 = G4RandGauss::shoot(0.,s_proj);      
    } while ((x0*x0 + y0*y0) > fR2World);
    fParticleGun->SetParticlePosition(G4ThreeVector(x0,y0,fZ0));     
  }
  
  fParticleGun->GeneratePrimaryVertex(anEvent); 
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......