A. Guzmán

JEM-EUSO observational capabilities for different UHE primaries.

for the JEM-EUSO Collaboration Cosmic rays with energies exceeding 1018 eV, usually defined as Ultra High Energy Cosmic Rays (UHECRs), allow the possibility to study physics at energies well beyond man made accelerators. State of the art UHECR detectors have reached unprecedented exposures and have pioneered the field of Extreme Energy Cosmic Rays (EECR), cosmic rays with energies exceeding 5×1019eV. The EECR flux is extremely small, of the order of 1 particle per square kilometer per century. The next generation of UHECR and EECR detectors are expected to increase the exposure by at least one order of magnitude. The JEM-EUSO mission, currently designed to be hosted onboard the JEM module of the ISS, consists of a ultra wide field of view UV-telescope orbiting the earth at an altitude of about 400 km. JEM-EUSO will look for fluorescent UV tracks produced by Extensive Air Showers (EAS) on the night side of the earth. According to the most recent studies, the JEMEUSO mission, can be transported onto the ISS by using the SpaceX’s Dragon spacecraft. In this work we present preliminary studies on the angular and energy reconstruction performances for different types of primaries (protons, iron nuclei and gamma rays). We compare our results with previously published results for the JEM-EUSO mission in a different configuration, and find a slight improvement.

The Angular Resolution of the JEM-EUSO Mission: an updated view

The Extreme Universe Observatory onboard the Japanese Experiment Module (JEM-EUSO) is a mission being developed to observe ultra high energy cosmic rays (UHECRs) from space. JEMEUSO consists of a wide field of view UV-telescope, assisted by an atmospheric monitoring system, designed to be mounted oboard the International Space Station. JEM-EUSO will observe the extensive air showers (EAS) induced by UHE cosmic particles with energies above 3× 1019 eV by using the earth’s atmosphere as a large detector. Due to the amount of monitored target volume JEM-EUSO is expected to reach an effective aperture of approx. 2× 105 km2 sr. During its lifetime, the mission will measure several hundred events with E > 5× 1019 eV significantly improving the statistics of the most energetic part of the spectrum above the observed cut-off. In the context of the JEM-EUSO Collaboration different mission profiles are being explored. A configuration actively investigated is a telescope, mainly based on the same technologies already employed in the baseline instrument, which can be launched with the SpaceX Falcon 9 rocket and transported to the ISS by the Dragon spacecraft. This new mission configuration allows a circular design of the optics which improves the performances. In this paper we present a brief study of the expected angular resolution of this new configuration.