source: trunk/source/geometry/solids/test/fred/src/GridParticleGun.cc

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//
//
// GridParticleGun.cc
//
// Implementation of grid particle gun
//

#include "GridParticleGun.hh"
#include "GridParticleGunMessenger.hh"

#include "G4PrimaryParticle.hh"
#include "G4ParticleTypes.hh"
#include "G4Event.hh"

//
// Constructor (no arguments)
//
GridParticleGun::GridParticleGun()
{
        SetDefaults();
}

//
// Constructor
//
GridParticleGun::GridParticleGun( G4ThreeVector theDirection,
                                  G4ThreeVector theOrigin,
                                  G4ThreeVector theGrid1,
                                  G4ThreeVector theGrid2,
                                  G4int theN1, G4int theN2 )
{
        SetDefaults();
        
        direction = theDirection;
        origin    = theOrigin;
        grid1     = theGrid1;
        grid2     = theGrid2;
        n1        = theN1;
        n2        = theN2;
        
        if (n1*n2 == 0) 
                G4Exception( "GridParticleGun created with n1 or n2 zero" );
}
        
        
//
// Destructor
//
GridParticleGun::~GridParticleGun() {
        delete messenger;
}


//
// SetDefaults
//
// Set defaults and create associated messenger
//
void GridParticleGun::SetDefaults()
{
        direction = G4ThreeVector(0,0,1);
        origin = G4ThreeVector(-2*m,-2*m,-2*m);
        grid1 = G4ThreeVector(4*m,0,0);
        grid2 = G4ThreeVector(0,4*m,0);
        n1 = 10;
        n2 = 10;
        
        
        particleType = G4Geantino::GeantinoDefinition();
        
        messenger = new GridParticleGunMessenger( this );
}


//
// GeneratePrimaryVertex
//
// Make the event.
//
// Note the strange notation of G4Event: we are allowed to have as many
// "primary" vertices as we wish.
//
void GridParticleGun::GeneratePrimaryVertex( G4Event *evt )
{
        G4ThreeVector   delta1 = grid1*(1.0/((G4double) n1)),
                                        delta2 = grid2*(1.0/((G4double) n2));

        G4int i = 0;
        G4ThreeVector iStart = origin;
        do {
                G4int j = 0;
                G4ThreeVector jStart = iStart;
                do {
                
                        //
                        // New particle: make it's vertex
                        //
                        G4PrimaryVertex *vertex = new G4PrimaryVertex( jStart, 0.0 );
                        
                        //
                        // ...then make it's self
                        //
                        G4PrimaryParticle *particle = new G4PrimaryParticle( particleType, direction.x(), direction.y(), direction.z() );
                        
                        //
                        // ...add it to the vertex, and add the vertex to the event
                        //
                        vertex->SetPrimary( particle );
                        evt->AddPrimaryVertex( vertex );
                        
                } while( jStart += delta2, j++ < n2 );
        } while( iStart += delta1, i++ < n1 );
}