G4ParticleGun.hh

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//
// G4ParticleGum
//
// Class description:
//
// This is a concrete class of G4VPrimaryGenerator. It shoots a particle of
// given type into a given direction with either a given kinetic energy or
// momentum.
// The position and time of the primary particle must be set by the
// corresponding set methods of the G4VPrimaryGenerator base class, otherwise
// zero will be set.
//
// The FAQ to this class is for randomizing position/direction/kinetic energy
// of the primary particle. But, G4ParticleGun does NOT have any way of
// randomization. Instead, the user's concrete implementation of
// G4VUserPrimaryGeneratorAction which transfer the G4Event object
// to this particle gun can randomize these quantities and set to this
// particle gun before invoking GeneratePrimaryVertex() method.
// Note that, even if the particle gun shoots more than one particles at one
// invokation of the GeneratePrimaryVertex() method, all particles have the
// same physical quantities. If the user wants to shoot two particles with
// different momentum, position, etc., should invoke GeneratePrimaryVertex()
// method twice and set quantities on demand to the particle gun.
 
// Author: Makoto Asai, 1997
// --------------------------------------------------------------------
#ifndef G4ParticleGun_hh
#define G4ParticleGun_hh 1
 
#include "globals.hh"
#include "G4VPrimaryGenerator.hh"
#include "G4ThreeVector.hh"
#include "G4ParticleDefinition.hh"
#include "G4PrimaryVertex.hh"
#include "G4ParticleMomentum.hh"
 
class G4Event;
class G4ParticleGunMessenger;
 
class G4ParticleGun : public G4VPrimaryGenerator
{
  public:
 
    G4ParticleGun();
    explicit G4ParticleGun(G4int numberofparticles);
    explicit G4ParticleGun(G4ParticleDefinition* particleDef, 
                  G4int numberofparticles = 1);
      // Costructors. "numberofparticles" is the number of particles to be
      // shot at one invokation of GeneratePrimaryVertex() method.
      // All particles are shot with the same physical quantities.
 
    ~G4ParticleGun() override;
 
    G4ParticleGun(const G4ParticleGun&) = delete;
    const G4ParticleGun& operator=(const G4ParticleGun&) = delete;
    G4bool operator==(const G4ParticleGun&) const = delete;
    G4bool operator!=(const G4ParticleGun&) const = delete;
 
    void GeneratePrimaryVertex(G4Event* evt) override;
      // Creates a primary vertex at the given point
      // and put primary particles to it.
 
    // Followings are the Set methods for the particle properties.
    // SetParticleDefinition() should be called first.  
    // By using SetParticleMomentum(), both particle_momentum_direction and
    // particle_energy(Kinetic Energy) are set.
    //
    void SetParticleDefinition(G4ParticleDefinition* aParticleDefinition);
    void SetParticleEnergy(G4double aKineticEnergy);
    void SetParticleMomentum(G4double aMomentum);
    void SetParticleMomentum(G4ParticleMomentum aMomentum);
    inline void SetParticleMomentumDirection(G4ParticleMomentum aMomDirection)
      { particle_momentum_direction =  aMomDirection.unit(); }
    inline void SetParticleCharge(G4double aCharge)
      { particle_charge = aCharge; }
    inline void SetParticlePolarization(G4ThreeVector aVal)
      { particle_polarization = aVal; }
    inline void SetNumberOfParticles(G4int i)
      { NumberOfParticlesToBeGenerated = i; }
    inline void SetParticleWeight(G4double w)
      { particle_weight = w; }
 
    inline G4ParticleDefinition* GetParticleDefinition() const
      { return particle_definition; }
    inline G4ParticleMomentum GetParticleMomentumDirection() const
      { return particle_momentum_direction; }
    inline G4double GetParticleEnergy() const
      { return particle_energy; }
    inline G4double GetParticleMomentum() const
      { return particle_momentum; }
    inline G4double GetParticleCharge() const
      { return particle_charge; }
    inline G4ThreeVector GetParticlePolarization() const
      { return particle_polarization; }
    inline G4int GetNumberOfParticles() const
      { return NumberOfParticlesToBeGenerated; }
    inline G4double GetParticleWeight() const
      { return particle_weight; }
 
  protected:  
 
     virtual void SetInitialValues();
 
     G4int                 NumberOfParticlesToBeGenerated = 0;
     G4ParticleDefinition* particle_definition = nullptr;
     G4ParticleMomentum    particle_momentum_direction;
     G4double              particle_energy = 0.0;
     G4double              particle_momentum = 0.0;
     G4double              particle_charge = 0.0;
     G4ThreeVector         particle_polarization;
     G4double              particle_weight = 1.0;
 
  private:
 
     G4ParticleGunMessenger* theMessenger = nullptr;
};
 
#endif