Data Acquisition System of the JEM-EUSO project

摘要

The Extreme Universe Space Observatory on the Japanese Experiment Module (JEM-EUSO) of the Inter-nationalSpace Station (ISS) is the first mission that will study from space Ultra High-Energy Cosmic Rays (UHECR).JEM-EUSO will observe Extensive Air Showers (EAS) produced by UHECRs traversing the Earth's atmosphere fromabove. For each event, the detector will make accurate measurements of the energy, arrival direction and nature of theprimary particle using a target volume far greater than what is achievable from ground. The corresponding increase instatistics will help to clarify the origin and sources of UHECRs as well as the environment traversed during productionand propagation. Possibly this will bring new light onto particle physics mechanisms operating at energies well beyondthose achievable by man-made accelerators. The spectrum of scientific goals of the JEM-EUSO mission includes asexploratory objectives the detection of high-energy gamma rays and neutrinos, the study of cosmic magnetic fields, andtests of relativity and quantum gravity effects at extreme energies. In parallel JEM-EUSO will systematically performobservation of the surface of the Earth in the infra-red and ultra-violet ranges, studying also atmospheric phenomena(Transient Luminous Effects).The apparatus is a 2 ton detector using Fresnel-based optics to focus the UV-light from5 channels. A multi-layer parallel architecture has been devised to handle the data flow and select valid triggers, reducing it to a ratecompatible with downlink constraints. Each processing level filters the event with increasingly complex algorithms usingASICs, FPGAs and DSPs in this order to reject spurious triggers and reduce the data rate.