The focusing elements in a 'classical' wide energy band neutrino beam, the horn and reflector, are toroidal lenses with a magnetic field between the inner and outer coaxial conductors. The aim of the horn/reflector system is to deviate pions and kaons (the parent particles of the neutrinos) into the direction of Gran Sasso. These magnetic lenses are pulsed with very high current (at CNGS: 150 kA for the horn, 180 kA for the reflector) for a short time (1 millisecond) around the proton beam pulse arrival at the target. The heat deposited by this current requires water cooling of the thin inner conductor (the inner conductor must be kept very thin in order to avoid significant absorption of pions/kaons). Further cooling may be needed due to the energy deposited by the particles passing through inner and outer conductor. These complex systems are designed based on many years of experience at CERN, e.g. from the WANF neutrino facility. Prototype tests are being performed in order to investigate the performance and reliability of the horn.

-> Pion trajectories in the CNGS horn / reflector system

-> Horn and Reflector at the WANF (CERN West Area Neutrino Facility)

-> Horn prototype tests

-> Horn / reflector powering system (in preparation)