generator.cpp

#include "generator.hh"

PrimaryGenerator::PrimaryGenerator()
{
	// 1 as in the number of events
	fParticleGun = new G4ParticleGun(1);
}

PrimaryGenerator::~PrimaryGenerator()
{
	delete fParticleGun;
}

void PrimaryGenerator::GeneratePrimaries(G4Event *event)
{
	// where particle information is stored
	G4ParticleTable *particleTable = G4ParticleTable::GetParticleTable();
	G4String particleName = "mu+";
	G4ParticleDefinition *particle = particleTable -> FindParticle(particleName);

	// position and momentum vectors
	G4ThreeVector pos(0.,0.,-1*m);
	G4ThreeVector mom(0.,0.,1.);

	// generate the particle 
	fParticleGun -> SetParticlePosition(pos);
	fParticleGun -> SetParticleMomentumDirection(mom);
	fParticleGun -> SetParticleEnergy(4.*GeV);
	fParticleGun -> SetParticleMomentum(500.*MeV);
	fParticleGun -> SetParticleDefinition(particle);

	fParticleGun -> GeneratePrimaryVertex(event);
}