University of Maryland
Observing Ultra-high Energy Cosmic Rays from Space with the JEM-EUSO Telescope
Cosmic rays are predominantly charged particles, among them protons, atomic nuclei, neutrinos and antimatter, arriving to the earth from all directions of the sky. Their energies reach from about 10^10 eV up to more than 10^20 eV. The origin of ultra-high energy cosmic rays (UHECR) with energies exceeding 10^18eV still remains a mystery. At this end of the cosmic ray spectrum the number of measured events drops to one event per km2 in 100 years - severely limiting our options to do research in this energy range. A space borne UHECR telescope would provide an unprecedented aperture and an all sky coverage. The JEM-EUSO Collaboration (Extreme Universe Observatory onboard the Japanese Experiment Module) is developing a space mission for the detection of UHECR. After deployment to the International Space Station it will monitor the atmosphere for UHECR induced air showers in the UV range. Utilizing the fluorescence technique it can observe cosmic ray events with energies exceeding 3x10^19 eV. A JEM-EUSO type apparatus will be the key experiment to address one of the most exciting questions in astrophysics - the origin of UHECR. In the scope of this talk we will discuss obstacles and advantages of the space approach on the example of instrument performance simulation studies of the JEM-EUSO telescope.