1. General Seminars

The Extreme Energy Events project: a sparse array of telescopes for cosmic radiation

by Marcello Abbrescia (BA)

Aula Bruno Touschek (LNF INFN)

Aula Bruno Touschek


The Extreme Energy Events project is meant to be the most extensive experiment to detect secondary cosmic particles in Italy. To this aim, a network of more than 50 telescopes has been built at CERN and installed in high schools distributed all over the Italian territory. Each EEE telescope comprises three layers of large area (80 x 160 cm2) Multi-gap Resistive Plate Chambers (MRPCs) with six 300 µm gas gaps each, based on the same technology used for the ALICE time-of-flight detector at LHC. The telescopes are capable of reconstructing the trajectories of the charged particles traversing them with a good angular resolution. The excellent performance of the EEE telescopes allows a large variety of studies, ranging from the measure of the local muon flux in a single telescope, to detecting extensive air showers producing time correlations in the same metropolitan area, to searching for large-scale correlations between showers detected in telescopes tens, hundreds or thousands of kilometers apart. Together with its scientific goals, the EEE Project also aims to involve high school students and teachers in the construction, testing and start-up of the EEE telescope in their school, later on in its maintenance and data-acquisition, and finally in the analysis of the data. During the last couple of years the experiment entered its maturity phase, and a great boost has been given to the EEE project by organizing simultaneous and centralized data taking with the whole telescope array contributing. The raw data from all telescopes are transferred to CNAF in Bologna, where they are automatically reconstructed and stored. The data are subsequently analyzed, to investigate various topics: variations of the rate of cosmic muons with time correlated with astrophysical events (Forbush decreases), upward going muons, muon lifetime, search for anisotropies in the muon angular distribution and for time coincidences between stations. In this presentation an overall description of the experiment is given, including the design, construction and performance of the telescopes. The operation of the whole array is also presented and the most recent physics results will be shown.