musrParticleGun.cc

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#include "musrParticleGun.hh"
#include "Randomize.hh"
#include "G4ios.hh"
#include "musrParticleGunMessenger.hh"

#include "G4ProcessManager.hh"
#include "G4VProcess.hh"

#include "G4ProcessVector.hh"

musrParticleGun::musrParticleGun()
{
  SetInitialValues();
  Messenger = new G4ParticleGunMessenger(this);
}

musrParticleGun::musrParticleGun(G4int numberofparticles)
{
  SetInitialValues();
  NumberOfParticlesToBeGenerated = numberofparticles;
}


musrParticleGun::~musrParticleGun()
{
  delete Messenger;
}

void musrParticleGun::SetInitialValues()
{
  NumberOfParticlesToBeGenerated = 1;
  particle_definition = 0;
  G4ThreeVector zero;
  particle_momentum_direction = (G4ParticleMomentum)zero;
  particle_energy = 0.0;
  particle_position = zero;
  particle_time = 0.0;
  particle_polarization = zero;
  particle_charge = 0.0;

}

void musrParticleGun::SetDecayTime(G4double d)
{
  decaytime=d;
}

void musrParticleGun::GeneratePrimaryVertex(G4Event* evt)
{
  if(particle_definition==0) return;

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


  // create new primaries and set them to the vertex
  G4double mass =  particle_definition->GetPDGMass();
  G4double energy = particle_energy + mass;
  G4double pmom = 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();
  for( G4int i=0; i<NumberOfParticlesToBeGenerated; i++ )
  {


    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());
    particle->SetProperTime(decaytime);
    //    G4cout<<"Muon decay time = " << decaytime/ns <<"ns. \n" <<G4endl;
    
    vertex->SetPrimary( particle );


  }

  evt->AddPrimaryVertex( vertex );
}

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