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///////////////////////////////////////////////////////////////////////////////
//
// MODULE:        G4SingleParticleSource.hh
//
// Version:      1.0
// Date:         5/02/04
// Author:       Fan Lei 
// Organisation: QinetiQ ltd.
// Customer:     ESA/ESTEC
//
///////////////////////////////////////////////////////////////////////////////
//
// CHANGE HISTORY
// --------------
//
// Version 1.0, 05/02/2004, Fan Lei, Created.
//      Based on the G4GeneralParticleSource class in Geant4 v6.0
//
///////////////////////////////////////////////////////////////////////////////
//
#include "G4PrimaryParticle.hh"
#include "G4Event.hh"
#include "Randomize.hh"
#include <cmath>
#include "G4ParticleTable.hh"
#include "G4Geantino.hh"
#include "G4ParticleDefinition.hh"
#include "G4IonTable.hh"
#include "G4Ions.hh"
#include "G4TrackingManager.hh"
#include "G4Track.hh"
#include "G4SingleParticleSource.hh"

G4SingleParticleSource::G4SingleParticleSource()
{
  // Initialise all variables
  // Position distribution Variables

  NumberOfParticlesToBeGenerated = 1;
  particle_definition = G4Geantino::GeantinoDefinition();
  G4ThreeVector zero;
  particle_momentum_direction = G4ParticleMomentum(1,0,0);
  particle_energy = 1.0*MeV;
  particle_position = zero;
  particle_time = 0.0;
  particle_polarization = zero;
  particle_charge = 0.0;
  particle_weight = 1.0;

  biasRndm = new G4SPSRandomGenerator();
  posGenerator = new G4SPSPosDistribution();
  posGenerator->SetBiasRndm(biasRndm);
  angGenerator = new G4SPSAngDistribution();
  angGenerator->SetPosDistribution(posGenerator);
  angGenerator->SetBiasRndm(biasRndm);
  eneGenerator = new G4SPSEneDistribution();
  eneGenerator->SetBiasRndm(biasRndm);

  // verbosity
  verbosityLevel = 0;

}

G4SingleParticleSource::~G4SingleParticleSource()
{}

void G4SingleParticleSource::SetVerbosity(int vL)
{
  verbosityLevel = vL;
  posGenerator->SetVerbosity(vL);
  angGenerator->SetVerbosity(vL);
  eneGenerator->SetVerbosity(vL);
  G4cout << "Verbosity Set to: " << verbosityLevel << G4endl;
}

void G4SingleParticleSource::SetParticleDefinition
  (G4ParticleDefinition* aParticleDefinition)
{
  particle_definition = aParticleDefinition;
  particle_charge = particle_definition->GetPDGCharge();
}

void G4SingleParticleSource::GeneratePrimaryVertex(G4Event *evt)
{
  if(particle_definition==NULL) return;

  if(verbosityLevel > 1)
    G4cout << " NumberOfParticlesToBeGenerated: "<<NumberOfParticlesToBeGenerated << G4endl;

  // Position stuff
  particle_position = posGenerator->GenerateOne();

  // create a new vertex
  G4PrimaryVertex* vertex = new G4PrimaryVertex(particle_position,particle_time);

  for( G4int i=0; i<NumberOfParticlesToBeGenerated; i++ ) {
    // Angular stuff
    particle_momentum_direction = angGenerator->GenerateOne();
    // Energy stuff
    particle_energy = eneGenerator->GenerateOne(particle_definition);
    
    if(verbosityLevel >= 2)
      G4cout << "Creating primaries and assigning to vertex" << G4endl;
    // create new primaries and set them to the vertex
    G4double mass =  particle_definition->GetPDGMass();
    G4double energy = particle_energy + mass;
    G4double pmom = std::sqrt(energy*energy-mass*mass);
    G4double px = pmom*particle_momentum_direction.x();
    G4double py = pmom*particle_momentum_direction.y();
    G4double pz = pmom*particle_momentum_direction.z();

    if(verbosityLevel > 1){
      G4cout << "Particle name: "<<particle_definition->GetParticleName() << G4endl; 
      G4cout << "       Energy: "<<particle_energy << G4endl;
      G4cout << "     Position: "<<particle_position<< G4endl; 
      G4cout << "    Direction: "<<particle_momentum_direction << G4endl;
    }
    G4PrimaryParticle* particle =
      new G4PrimaryParticle(particle_definition,px,py,pz);
    particle->SetMass( mass );
    particle->SetCharge( particle_charge );
    particle->SetPolarization(particle_polarization.x(),
			      particle_polarization.y(),
			      particle_polarization.z());
    // Set bweight equal to the multiple of all non-zero weights
    particle_weight = biasRndm->GetBiasWeight();
    // pass it to primary particle
    particle->SetWeight(particle_weight);

    vertex->SetPrimary( particle );
      
  }
  // now pass the weight to the primary vertex. CANNOT be used here!
  //  vertex->SetWeight(particle_weight);
  evt->AddPrimaryVertex( vertex );
  if(verbosityLevel > 1)
    G4cout << " Primary Vetex generated !"<< G4endl;   
}