ExUCNPrimaryGeneratorAction.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 exoticphysics/ucn/src/ExUCNPrimaryGeneratorAction.cc
/// \brief Implementation of the ExUCNPrimaryGeneratorAction class
//
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
#include "ExUCNPrimaryGeneratorAction.hh"
 
#include "ExUCNDetectorConstruction.hh"
 
#include "G4Event.hh"
#include "G4ParticleGun.hh"
#include "G4ParticleTable.hh"
#include "G4ParticleDefinition.hh"
#include "Randomize.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
ExUCNPrimaryGeneratorAction::ExUCNPrimaryGeneratorAction(void)
{
  G4int n_particle = 1;
  fParticleGun  = new G4ParticleGun(n_particle);
 
  G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
 
  G4ParticleDefinition* particle = particleTable->FindParticle("neutron");
  fParticleGun->SetParticleDefinition(particle);
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
ExUCNPrimaryGeneratorAction::~ExUCNPrimaryGeneratorAction()
{
  delete fParticleGun;
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void ExUCNPrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
{
  // This function is called at the begining of event
 
  fParticleGun->SetParticlePosition(G4ThreeVector(0.0, 0.0, 0.0));
  fParticleGun->SetParticlePolarization(G4ThreeVector(0,1,0));
 
  G4double particleEnergy = 1e-9*eV + G4UniformRand()*(1e-7*eV-1e-9*eV);
  fParticleGun->SetParticleEnergy(particleEnergy);
 
  G4double theta = 2*pi*G4UniformRand();
  G4double phi = std::acos(1-2*G4UniformRand());
  if (phi > pi/2 && phi < pi) phi = pi-phi;
 
  G4double z = std::sin(phi)*std::cos(theta);
  G4double x = std::sin(phi)*std::sin(theta);
  G4double y = std::cos(phi);
 
  fParticleGun->SetParticleMomentumDirection(G4ThreeVector(x,y,z));
 
  fParticleGun->GeneratePrimaryVertex(anEvent);
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......