Chicago Air Shower Array

The Chicago Air Shower Array (CASA) is an experimental facility designed to study ultra-high-energy cosmic rays (UHECRs) by detecting air showers that result from the interaction of these cosmic rays with the Earth's atmosphere. Located at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, CASA was developed as part of a broader set of experiments aimed at understanding the origins and characteristics of cosmic rays that have energies significantly greater than those produced by human-made accelerators.