The figure below shows, for a few selected families of particles exiting the CNGS target, the action of horn and reflector on the trajectories. For a family of 35 GeV trajectories with production angles from 2.3 to 19.4 mrad, the horn alone achieves a parallel beam to Gran Sasso (middle), while for other energies or production angles, the action of the reflector is needed. (Note: "pt" stands for the transverse momentum of the particles.). Simulations have been performed for large numbers of positively and negatively charged particle trajectories in the CNGS two-horn system.