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// $Id: PrimaryGeneratorAction.cc,v 1.1 2007/10/15 16:20:23 maire Exp $
// GEANT4 tag $Name: geant4-09-03-cand-01 $
//
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#include "PrimaryGeneratorAction.hh"

#include "DetectorConstruction.hh"
#include "HistoManager.hh"

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

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PrimaryGeneratorAction::PrimaryGeneratorAction(DetectorConstruction* det,
                                               HistoManager* histo)
:detector(det),histoManager(histo)					       
{
  particleGun  = new G4ParticleGun(1);
  G4ParticleDefinition* particle
           = G4ParticleTable::GetParticleTable()->FindParticle("e-");
  particleGun->SetParticleDefinition(particle);
  particleGun->SetParticleEnergy(1*MeV);  
  particleGun->SetParticleMomentumDirection(G4ThreeVector(0.,0.,1.));
}

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PrimaryGeneratorAction::~PrimaryGeneratorAction()
{
  delete particleGun;
}

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void PrimaryGeneratorAction::RunInitialisation(G4double effWall, G4double massR)
{
  //this function is called at beginning of run
  //
  cavityThickness = detector->GetCavityThickness();      
  effWallThick = effWall;
  massWallRatio  = massR;    
    
  Nwall = Ncavity = 0;
}

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void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
{
  //this function is called at the begining of event
  //      
  G4double Zvertex;
  if (G4UniformRand() < massWallRatio) {
    Zvertex = 0.5*cavityThickness + G4UniformRand()*effWallThick;
    if (G4UniformRand() < 0.5) Zvertex = -Zvertex;
    Nwall++;
  } else {
    Zvertex = (G4UniformRand() - 0.5)*cavityThickness;
    Ncavity++;
  }
  
  particleGun->SetParticlePosition(G4ThreeVector(0., 0., Zvertex));  
  particleGun->GeneratePrimaryVertex(anEvent);
  
  //histograms
  //
  histoManager->FillHisto(1,Zvertex);
  histoManager->FillHisto(2,particleGun->GetParticleEnergy()); 
}

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