Monitoring the long term stability of civil buildings through the MRPC telescopes of the EEE Project

Cosmic ray muons are a penetrating component of extensive air showers created in the Earth atmosphere by the interaction of highly energetic primary particles, mostly protons, which continuously bombard our Planet. The secondary cosmic radiation is the result of the complex interplay between the production cross section and the interaction mechanisms with the atmosphere (including the energy loss, multiple scattering and particle decay). Cosmic muons have been considered since several decades as a powerful probe to exploit our environment, from muography of volcanoes to absorption radiography of possible hidden rooms inside large structures, such as Pyramids, to the detection of high-Z illicit nuclear materials inside containers and many other applications of social interest. This paper discusses the possibility to employ the Multigap 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. For this application the average direction of the cosmic muon tracks passing through the MRPC telescope and an additional detector located some distance apart in the same building may be reconstructed with good precision and any small variation over long time acquisition periods may be monitored. The performance of such setup is discussed and experimental results from first coincidence measurements obtained with a 40 60 cm2 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.