Three-dimensional muon imaging of cavities inside the Temperino mine (Italy)

Abstract

Muon radiography (muography) is an imaging technique based on atmospheric muon absorption in matter that allows to obtain two and three-dimensional images of internal details of hidden objects or structures. The technique relies on atmospheric muon flux measurements performed around and underneath the object under examination. It is a non-invasive and passive technique and thus can be thought of as a valid alternative to common prospecting techniques used in archaeological, geological and civil security fields. This paper describes muon radiography measurements, in the context of archaeological and geological studies carried out at the Temperino mine (LI, Tuscany, Italy), for the search and three-dimensional visualisation of cavities. This mine has been exploited since Etruscan times until recently (1973), and is now an active tourist attraction with public access to the tunnels. Apart from the archaeological interest, the importance of mapping the cavities within this mine lies in identifying the areas where the extraction ores were found and also in the safety issues arising from the tourist presence inside the mine. The three-dimensional imaging is achieved with two different algorithms: one involving a triangulation of two or more measurements at different locations; the other, an innovative technique used here for the first time, is based on the back-projections of reconstructed muon tracks. The latter requires only a single muographic data tacking and is to be preferred in applications where more than one site location can be difficult to access. Finally the quality of the three-dimensional muographic imaging was evaluated by comparing the results with the laser scan profiles obtained for some known cavities within the Temperino mine.

First experimental results of the cosmic time synchronizer for a wireless, precise, and perpetual time synchronization system

“…A large fraction of these muons are relativistic in nature and they penetrate the atmosphere losing only a small fraction of their energy predominantly by ionization. The penetrative nature of muons has been utilized to visualize the inside structures of gigantic objects such as volcanoes, 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 local ocean dynamics 40 cultural heritage, 41 , 42 , 43 , 44 , 45 , 46 underwater/underground positioning 47 and navigation, 48 and postquantum cryptography. 49 …”

Muography as a support technique for non-invasive research and three-dimensional localization of tombs in archaeological sites: a case study from Palazzone Necropolis (Perugia – Italy)

“…The technique is applicable up to distances from the detector equal to ∼ 𝑙/𝜎 𝛼 where 𝑙 is the distance between the tracking planes and 𝜎 𝛼 the detector angular resolution. This technique was applied in [14,15].…”

“…The air thickness of the cavity was estimated, as explained in [14], by combining the knowledge of the depth of the target hill and the density values found in the angular directions that identify Tomb n.11. The result is shown in figure 6 (right), observing that the thicknesses found (7-12 m) are compatible with the real air thickness of the cavity.…”

Muon Imaging for Cu-Fe Ore Shoot Identification: Results and Next Challenges

“…The transmission-based muography (TM) technique used to obtain transmission and density maps relies on an accurate track reconstruction of hitting muons arriving within the MIMA muon detector acceptance cone (approximately ±60 • with respect to the zenith; Figure 2). The TM relies on two configuration measurements [4,5]: target and free-sky. The former refers to the muon flux measurement conducted inside the mine gallery, where the rock mass between the detector and the surface is defined as the target, whereas the latter refers to the muon flux measurement conducted outside the mine, only pointing to the sky (free-sky), while maintaining the same orientation as the underground target measurement.…”

“…In this context, the muon imaging technique is developing as a cost-effective and trustworthy booster for both invasive and noninvasive consolidated survey techniques in the underground mining field [1,2,3,4]. For this purpose, the MIMA detector prototype (Muon Imaging for Mining and Archaeology; a cubic detector of 0.4 × 0.4 m 2 active surface), implemented during the MIMA-SITES research project, was used [1,4,5]. The MIMA tracker is a small and rugged muon tracker developed by physicists of the National Institute for Nuclear Physics (INFN) and the Department of Physics and Astronomy of Florence [6,7,8].…”