AirWatch

Home page of the Experiment: http://www.euso-mission.org/

The nature of the UHECR is one of the most intriguing and controversial chapters of modern astro-particle physics. A significant increase of the observed number of UHECR (about twenty events observed up to now) would help to understand the mystery of their nature and origin, the production and transport mechanisms and the shape of the spectrum the highest energies. However the UHECR flux reaching the Earth is very small and therefore a complex experimental apparatus is required for their observation.

The EAS observation from space by means of a fast and high-granularity photo-detector allows to reconstruct the longitudinal EAS profile, providing the energy and arrival direction, as well as to gather information about the nature of the primary particle. EUSO will observe the Earth night atmosphere by looking to nadir with a large aperture and large field of view optics focusing the image on the focal surface photo-detector. The peculiar characteristics of the EAS, especially the kinematical ones, allow one to distinguish them from the various backgrounds, because those have a typically different space-time development.

The experiment aims to extend the observed energy spectrum of cosmic rays beyond 5·1019 eV with a statistics of a few thousands events and to obtain a map of the arrival directions of the EHECR extended to the entire sky. In particular the possible flux of EHE cosmic neutrinos might be observed.