Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Siena

The muon telescopes of the Extreme Energy Events (EEE) experiment are based on MultigapResistive Plate Chambers (MRPC). The EEE network is composed, so far, of 53 telescopes, each made of three MRPC detectors; it is organized in clusters and single telescope stations distributed all over the Italian territory and installed in High Schools, covering an area larger than 3 x 10(5) km(2). The study of Extensive Air Showers (EAS), that is one of the goal of the project, requires excellent performance in terms of time and spatial resolution, efficiency, tracking capability and long term stability. The data from two recent coordinated data taking periods, named Run 2 and Run 3, have been used to measure these quantities and the results are here reported, together with a comparison with expectations and with the results from a beam test performed in 2006 at CERN.

In this paper the first study of the upward going events detected by the telescopes of the Extreme Energy Event (EEE) project is reported. The EEE project consists of a detector array of Multigap Resistive Plate Chambers located at selected sites on the Italian territory. During autumn 2014 the first coordinated data taking period took place and around one billion candidate tracks were collected. Among them, of particular interest is the sample of particles which cross the telescopes from below. The results obtained demonstrate that the EEE telescopes can distinguish the electrons produced as decay products of cosmic muons stopped in the ground, or in the last chamber of the telescopes themselves, confirming the excellent performance of the system for the investigation of intriguing cosmic phenomena.

The Extreme Energy Events project (EEE) is aimed to study Extensive Air Showers (EAS) from primary cosmic rays of more than 10(18) eV energy detecting the ground secondary muon component using an array of telescopes with high spatial and time resolution. The second goal of the EEE project is to involve High School teachers and students in this advanced research work and to initiate them in scientific culture: to reach both purposes the telescopes are located inside High School buildings and the detector construction, assembling and monitoring - together with data taking and analysis - are done by researchers from scientific institutions in close collaboration with them. At present there are 42 telescopes in just as many High Schools scattered all over Italy, islands included, plus two at CERN and three in INFN units. We report here some preliminary physics results from the first two common data taking periods together with the outreach impact of the project.

The Extreme Energy Events (EEE) Project is meant to be the most extensive experiment to detect secondary cosmic particles in Italy. To this aim, more than 50 telescopes have been built at CERN and installed in high schools distributed all over the Italian territory. Each EEE telescope comprises three large area Multigap Resistive Plate Chambers (MRPCs) and is capable of reconstructing the trajectories of the charged particles traversing it with a good angular resolution. The excellent performance of the EEE telescopes allows a large variety of studies, from measuring 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. In addition to its scientific goal, the EEE Project also has an educational and outreach objective, its aim being to motivate young people by involving them directly in a real experiment. High school students and teachers are involved in the construction, testing and start-up of the EEE telescope in their school, then in its maintenance and data-acquisition, and later in the analysis of the data. During the last couple of years a great boost has been given to the EEE Project through the organization of simultaneous and centralized data taking with the whole telescope array. The raw data from all telescopes are transferred to CNAF (Bologna), where they are reconstructed and stored. The data are currently being analyzed, looking at various topics: variation of the rate of cosmic muons with time, upward going muons, muon lifetime, search for anisotropies in the muon angular distribution and for time coincidences between stations. In this paper 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 by showing the most recent physics results.

This paper discusses the possibility to employ the Multi-gap Resistive Plate Chambers (MRPC) of the Extreme Energy Events (EEE) Project as muon tracking detectors to monitor the long term stability of civil buildings and structures when used in conjunction with additional detectors, to reconstruct the average direction of the cosmic muon tracks passing through both devices and any small variation over long time acquisition periods. The performance of such setup is discussed and preliminary experimental coincidence results obtained with a 40× 60 cm 2 scintillator detector operated in the same building with one of the EEE telescopes, at about 15 m vertical distance from it, are presented. Simple Monte Carlo and GEANT simulations were also carried out to evaluate typical acceptance values for the operating conditions employed so far, to extrapolate to other geometrical configurations, and to evaluate multiple scattering effects.

The muon telescopes of the Extreme Energy Events (EEE) Project [1] are made of three Multigap Resistive Plate Chambers (MRPC). The EEE array is composed, so far, of 59 telescopes and is organized in clusters and single telescope stations distributed all over the Italian territory. They are installed in High Schools with the aim to join research and teaching activities, by involving researchers, teachers and students in the construction, maintenance, data taking and data analysis. The unconventional working sites, mainly school buildings with non-controlled environmental parameters and heterogeneous maintenance conditions, are a unique test field for checking the robustness, the low-ageing features and the long-lasting performance of the MRPC technology for particle tracking and timing purposes. The measurements performed with the EEE array require excellent performance in terms of time and spatial resolution, efficiency, tracking capability and stability. The data from two recent coordinated data taking periods, named Run 2 and Run 3, have been used to measure these quantities and the results are described, together with a comparison with expectations and with the results from a beam test performed in 2006 at CERN.

The Extreme Energy Events (EEE) experiment is the largest system in the world completely implemented with Multigap Resistive Plate Chambers (MRPCs). Presently, it consists of a network of 59 muon telescopes, each made of 3 MRPCs, devoted to the study of secondary cosmic rays. Its stations, sometimes hundreds of kilometers apart, are synchronized at a few nanoseconds level via a clock signal delivered by the Global Positioning System. The data collected during centrally coordinated runs are sent to INFN CNAF, the largest center for scientific computing in Italy, where they are reconstructed and made available for analysis. Thanks to the on-line monitoring and data transmission, EEE operates as a single coordinated system spread over an area of about 3 × 105 km2. In 2017, the EEE collaboration started an important upgrade program, aiming to extend the network with 20 additional stations, with the option to have more in the future. This implies the construction, testing and commissioning of 60 chambers, for a total detector surface of around 80 m2. In this paper, aspects related to this challenging endeavor are covered, starting from the technological solutions chosen to build these state-of-the-art detectors, to the quality controls and the performance tests carried on.

The Extreme Energy Events observatory is an extended muon telescope array, covering more than 10 degrees both in latitude and longitude. Its 59 muon telescopes are equipped with tracking detectors based on Multigap Resistive Plate Chamber technology with time resolution of the order of a few hundred picoseconds. The recent restrictions on greenhouse gases demand studies for new gas mixtures in compliance with the relative requirements. Tetrafluoropropene is one of the candidates for tetrafluoroethane substitution, since it is characterized by a Global Warming Potential around 300 times lower than the gas mixtures used up to now. Several mixtures have been tested, measuring efficiency curves, charge distributions, streamer fractions and time resolutions. Results are presented for the whole set of mixtures and operating conditions, focusing on identifying a mixture with good performance at the low rates typical of an EEE telescope.

Due to their penetration capability, cosmic muons may provide a way to monitor the alignment and possible long term deformations of large structures, such as historical or other civil buildings. The basic idea behind this possibility is to look for any misalignment between position-sensitive detectors, fixed to different parts of the structure, relative to the original alignment condition. In this paper we discuss the possibility of employing Multigap Resistive Plate Chambers (MRPC) as tracking devices, operating them in coincidence with additional detectors without tracking capability. One of the MRPC telescopes (size 158× 82 cm2) of the Extreme Energy Events (EEE) project, installed in the underground floor at the Department of Physics and Astronomy in Catania, was used together with a 40× 60 cm2 scintillator-based detector, located at about 16 m vertical distance, on the third floor of the same building. Coincidence measurements were carried out over a period of about two months by shifting the position of the smaller detector, to mimic the movement of the structure. Plans for future studies with different detectors and under different geometrical configurations are also discussed.

During the summer of 2018 the PolarQuest 2018 ship expedition cruised to the North Pole region. One of the four experiments installed on the boat was PolarquEEEst, a cosmic ray detector developed within the Extreme Energy Events project. The PolarquEEEst purpose is to measure the cosmic ray flux at sea level and at extreme latitudes in a very poorly explored region. The POLA-01 detector, designed to fit the strong requirements for an on-board installation, is composed of two planes (four tiles each) of scintillators. Two similar detectors POLA-02 and POLA-03 were also installed in fixed locations, in Norway and Italy respectively, to be used as a reference. The high stability of the POLA-01 detector in the whole period allowed to collect data from $66^\circ$\,N to $82^\circ$\,N latitudes and to look for variations on the cosmic ray flux when moving towards the North Pole, using POLA-02 and POLA-03 measurements to remove time-fluctuations affecting the flux. The first results collected during the expedition will be reported. The PolarquEEEst mission continued its trip in Italy to perform measurement down to $35^\circ$\,N with POLA-01, which has been recently installed with POLA-03 and the newely built POLA-04 in the Svalbard islands to collect data for a long period.

Abstract Due to their efficiency, tracking capabilities and long-term operational conditions, Multigap Resistive Plate Chambers (MRPC) may be used in a stable location in coincidence with additional detectors fixed to other parts of a civil building, to detect relative displacements of different parts of the building due to long term deformations of the structure. In this contribution we report the results of two different measurements carried out in the Department of Physics and Astronomy of the University of Catania (with three floors above the ground and an underground basement), using one of the MRPC telescopes of the Extreme Energy Events project, in coincidence with two scintillator-based muon telescopes located in various positions inside the building. Experimental results obtained by these measurements campaigns over a period of about three months are reported, together with a discussion about the performance of the technique. The sensitivity of the method is also discussed by means of Monte Carlo simulations.

Abstract EEE is an extended cosmic ray observatory, covering more than 10 degrees in latitude and longitude. The relative distances between clusters of telescopes reached the 1200 km, allowing the search for rare long distance correlations between cosmic showers. On the other side each EEE telescope is capable of measuring the flux of secondary particles, opening to the study of low energy phenomena such as solar activity and Forbush decreases. An introduction to the observaotry and updates on the main scientific results are presented. Last updates on the searches for rare correlated showers, with a set of long distance correlation candidate events are also reported.

The Extreme Energy Events (EEE) experiment is a strategic project of Centro Fermi dedicated to the study of extreme energy cosmic rays with an innovative outreach approach: high school students are directly involved in the experiment and play a primary role. EEE exploits a network of muon tracking telescopes constituted by three large area MRPCs. In this work we describe the detector design and the construction phase which is performed at CERN by high school students and teachers. The experiment is coordinated by Centro Fermi with collaboration from INFN, CERN, Ministero dell'Università e della Ricerca (MIUR). Nowadays $52$ telescope are installed all over Italy ($3~10^5~km^2$) and a total of 100 institutes participate monitoring the quality of the data and analysing them. The EEE Project is still expanding to enlarge the network, involving more schools.