A method to identify cosmic-ray nuclei in the knee region using high-resolution Cerenkov cameras on the ground

A new method for making high-resolution ground-based measurements of the energy and charge of cosmic ray primaries in the region of the knee is presented. The method works by measuring the component of Cerenkov radiation (i.e., “Direct Cerenkov”) emitted directly by cosmic ray nuclei prior to their first hadronic interaction in the atmosphere. A dedicated ground-based Direct Cerenkov detector could achieve model-independent charge and energy resolution as good as 15%, on an event-by-event basis. This has potential applications in many fields in particle astrophysics.