Muography with nuclear emulsions - Stromboli and other projects ANNALS OF GEOPHYSICS, 60, 1, 2017, S0111; doi:10.4401/ag-7386 S0111 Muography with nuclear emulsions - Stromboli and other projects Valeri Tioukov1,2,*, Giovanni De Lellis1,2, Paolo Strolin1,2, Lucia Consiglio1,2, Andrey Sheshukov1,2, Massimo Orazi3, Rosario Peluso4,5, Cristiano Bozza4,5, Chiara De Sio4,5, Simona Maria Stellacci4,5, Chiara Sirignano6,7, Nicola D’Ambrosio8, Seigo Miyamoto9, Ryuichi Nishiyama9, Hiroyuki K.M. Tanaka9 1 Università di Napoli Federico II, Dipartimento di Fisica, Naples, Italy 2 Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Napoli, Naples, Italy 3 Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Napoli - Osservatorio Vesuviano, Naples, Italy 4 Università di Salerno, Dipartimento di Fisica “E. R. Caianiello”, Salerno, Italy 5 Istituto Nazionale di Fisica Nucleare (INFN), Gruppo Collegato di Salerno, Salerno, Italy 6 Università di Padova, Dipartimento di Fisica e Astronomia “Galileo Galilei”, Padova, Italy 7 Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Padova, Padova, Italy 8 Istituto Nazionale di Fisica Nucleare (INFN), Laboratori Nazionali del Gran Sasso, Assergi (L’Aquila), Italy 9 Earthquake Research Institute, The University of Tokyo, Tokyo, Japan ABSTRACT The muon radiography is a novel imaging technique to probe the volca- noes interior, using the capability of high energy cosmic ray muons to penetrate large thicknesses of rock. In this way it is possible to derive a 2D density map along the muon trajectory of volcanic edifices and deduce information on the variations in the rock density distribution, like those expected from dense lava conduits, or low density magma supply paths. This method is applicable also to study geological objects as glaciers, faults, oil underground reservoirs, engineering constructions, where a density contrast is present. Nuclear emulsions are well suited to be em- ployed in this context for their excellent angular resolution; they are com- pact and robust detectors, able to work in harsh environments without need of power supply. On the other side, a long exposure time is required for a reasonable detector surface (~10 m2) in order to collect a sufficient statistics of muons, and a quasi-real time analysis of the emulsion data is rather difficult due to the scanning time needed by the optical micro- scopes. Such drawback is on the way to be overcome thanks to a recent R&D program on ultra-fast scanning systems. Muon radiography tech- nique, even if limited to the summit part of the volcano edifice, represents an important tool of investigation, at higher spatial resolution, comple- mentary to the conventional geophysics techniques. The first successful result in this field was obtained by a Japanese group that observed in 2007 the conduit structure of Mt. Asama. Since 2010, other interesting volca- noes have been probed with the same method: Stromboli in 2011, Mt. Teide in 2012 and La Palma in 2014. Here we discuss the muon imaging technique reporting the nuclear emulsion detector design exposed at Stromboli and results of the data analysis. 1. The muon radiography technique The internal structure of active volcanoes, is one of the most important geophysical questions. Cur- rently, the shallow Earth crust is explored in great detail with echo-sounding, electromagnetic or gravimetric techniques, but it cannot be well resolved because of its strong structural heterogeneity and the potential dif- ficulty to be accessed. Actually such indirect methods suffer from inherent ambiguity, require spatially dense measurements in active areas and may not provide suf- ficient spatial resolution in the uppermost part of the conduit system. The muon radiography performed with cosmic-ray muons represents a complementary method able to provide a direct snapshot of the density profile in a volcano. In someway it is similar to the stan- dard medical radiography: it allows to view inside vol- canoes from a certain distance, thus reducing the risk for the operator, using instead of X-rays, atmospheric muon particles from cosmic rays. Cosmic muons are the products of pion and kaon decays originated from the hadronic interaction of the primary cosmic rays (mainly protons and alpha particles) with the atmos- Article history Received September 18, 2016; accepted October 5, 2016. Subject classification: Muon radiography, Nuclear emulsion, Stromboli, Volcano, Tracking detector. pheric nuclei. Muons are the charged particles with the highest penetration capability in the matter. Their mass (about 200 times the electron mass) and their long life- time allow them to propagate through the layers of the atmosphere toward the Earth’s ground from any direc- tion. Cosmic rays reach very high energies, which are partially inherited by the muons. The muon average en- ergy at the sea level is around 4 GeV near the zenith [Gaisser 1990], but there are very large tails, up to sev- eral TeV. The muon flux intensity and energy distribu- tion depend on the zenith angle. The nearly horizontal muons, are more interesting for the radiography pur- pose because their higher energy, allows them pene- trate larger rock thicknesses. A muon detector is usually positioned on a slope of the volcano as schematically shown in Figure 1, pointing toward a prominent rock region of interest in such a way it’s possible to derive results for the rock portion located above the detector. Typically the meas- ured fluxes are relatively low and strongly dependent on the amount of the thickness crossed. For instance, a muon telescope with a surface of the order of 1 m2 with 1 steradian aperture angle can record about 103 muons per day crossing a rock thickness equivalent to 2 km of water. The energy spectrum of the atmos- pheric muons is well known; thus assuming also the precise knowledge of the mountain shape and a well understood muon detector it is possible to infer a map of the rock density distribution, by using the informa- tions on the attenuation and the absorption of the muon flux. Since denser materials absorb more muons (like dense materials such as bones absorb more X- rays), this provides a basis for producing shadow im- ages of the volcano interior. An important advantage of the technique is the spatial resolution that can be achieved: whereas current indirect methods can pro- vide information with a spatial resolution of some hun- dreds of meters, muon radiography may provide mapping of internal structures to a resolution of some tens of meters. The resolution in solving the density contrast depends on the thickness of the rock traversed by the muons: the thicker it is, the fainter the muon flux is and the longer it takes to collect enough muons for a picture. The time needed can thus range from some weeks to several months. Another interesting feature of this technique, is the possibility to perform a tomo- graphic measurement by placing two or more cosmic ray telescopes around the object of interest. 2. Nuclear emulsions for muon recording Mainly there are two kind of detectors that can be used for muon radiography purpose: real time detec- tors (like plastic scintillators or wire chambers) and nu- clear emulsion films used in our observations. Emulsion detectors, have an incomparable position and intrinsic angular resolution (less than 1 µ and a 1 mrad, respec- tively), high data storage capabilities, mechanical robust- ness and compactness. They are not real time detectors and differently from the electronic ones do not require power supply and electronic front-end readout systems. Moreover, their quite simple implementation in harsh environments like the ones encountered in active zones of a volcano and their easy portability, makes them ideal for geological applications. The very recent R&D pro- gram on new generation faster scanning systems cur- rently in use for the OPERA experiment on neutrino oscillation search [Acquafredda et al. 2009; Agafonova et al. 2010, 2013, 2014] have recently encouraged the em- ployment of nuclear emulsions as tracking detector in this field allowing to exploit widely their potential. The nuclear emulsion films used in our detector are made of two layers 45 µm thick of AgBr crystals suspended in an organic gelatine poured on a plastic base of 200 µm. When a charged particle crosses the sensitive layer, some micro-crystals on the particle tra- jectory record its path as sequence of dark aligned grains (0.3 -1 µm diameter) as shown in Figure 2 which can be analyzed after a chemical development of the films, by an optical microscope. The grain density in the emulsion is about 35/100 µm optimized for a min- TIOUKOV ET AL. 2 Figure 1. The principle of muography. Figure 2. Cross sectional view of a nuclear emulsion layer. 3 imum ionizing particle. As final response, the detector will provide a precise measurement of the incident angle of the muons. A detailed description of the nu- clear emulsion detector is given in Nakamura et al. [2006]. The first experiments of muon radiography of volcanoes with nuclear emulsion technique have been successfully conducted on Mt. Asama [Tanaka et al. 2007a] and Showa-Shinzan [Tanaka et al. 2007b] in Japan. After that, new emulsion projects involving Ital- ian laboratories have been carried on: Stromboli vol- cano in 2011, Teide mountain radiography (2012) and La Palma exposure (2014) in Tenerife. 3. The Stromboli survey Stromboli is a composite strato-volcano that steeply reaching ~900 m above sea level, allows to image a large portion of the volcano edifice by muon radiogra- phy. The Stromboli activity is marked out by a shallow seismicity occurring at about 200 m depth below the cone [Chouet et al. 2007] associated with eruptions as well as the continuous volcanic tremor and intermit- tent explosions of gas jets and volcanic materials that are concentrated at depths shallower than 200 m be- neath the summit crater [Auger et al. 2006]. One of the most interesting regions is the so-called Sciara del Fuoco since, according to some theoretical models of the vol- canic activity, the main explosion mechanism would be due to some cracks opening from the main conduit of this region [Macedonio 2009]. An advanced geophysical system is installed on the volcano slopes, for monitoring several parameters (seis- mic, infrasounds, thermal infrared, ground deforma- tion, chemical composition of fumaroles), but the precise internal structure of the region below craters is not completely understood yet. The muon radiogra- phy could be an independent tool for investigating the inner structure of the cone and revealing the location and extent of the conduits that feed the continuous ex- plosions. The region where the structures are expected is indicated by a black line in Figure 3. Possible cracks or channels transverse dimensions is expected as 10 me- ters or less. This resolution could be reached by muon radiography in a favorable conditions. 3.1. The muon telescope An emulsion telescope with an area of 0.96 m2 was installed in the end of 2011 at 640 m of altitude point- ing toward the Sciara region. The apparatus consists of 8 modules (Figure 4) each one equipped with 10 emul- sion cells as shown in Figure 5. Each of them is made of 2 doublets of emulsion films individually vacuum-packed in light shield en- velopes, coated on both sides of a central metal plate of 26 cm × 80 cm size and 5 mm thick (Figure 6). The emul- sion doublets are coated to the central plate by 2 layers of elastic rubber while additional inox steel plates inte- grate the module structure, in such way to guarantee flatness and at the same time shield the soft component of cosmic rays. The total amount of emulsion films per module is 40. The total weight of one module is 26 kg while the overall weight of 8 modules including also the support frame is about 250 kg. In order to avoid possible rotation effects of any emulsion film a rigid support frame was realized. The detector position and orientation was obtained by recording GPS data of two outer limits of the structure. The detector exposure went on for 5 months (from the end of October to the end of March); during this period, a continuous temperature MUOGRAPHY WITH NUCLEAR EMULSIONS - STROMBOLI AND OTHER PROJECTS Figure 3. A south-east view of Stromboli. The Sciara del Fuoco re- gion and the active craters are indicated. Figure 4. Picture of the detector structure. Figure 5. Front view of a single detector module. monitoring was performed in order to control that the emulsion working temperature would be kept inside an acceptable range (15°- 25°). After the exposure, the detector was disassembled and the emulsions chemi- cally developed. During the data taking, the emulsion films were held very tightly, in order to guarantee a pat- tern matching between consecutive films. 3.2. Data analysis and preliminary results Emulsion readout is performed by fast automatic microscopes (Figure 7) [Arrabito et al. 2006] with a nominal scanning speed of 24 cm2/h recently upgraded to 40 cm2/h by keeping the current hardware configu- ration [Alexandrov 2013]. A sequence of 16 tomographic images is taken in each emulsion layer, with a step of 2.5 µm in order to reconstruct the threedimensional tracks. All charged particle tracks, just after their pro- duction are recorded in each film up to the develop- ment phase, with no time information. The event time reconstruction is done offline by geometrical coinci- dences, that means at least two emulsion films are needed to get position pattern matching. In this way only tracks collected during the observation period match between adjacent films while the fake track coincidences due to combinatorial background are discarded. After the of- fline track reconstruction procedure widely detailed in Arrabito et al. [2007], it is possible to draw a bidimen- sional histogram with the reconstructed track density (Figure 8), TX and TY here are the directional tangents in respect to the telescope main axis. In this coordinate system the mountain contour visible by detector using the muons should coincide perfectly with the usual photo made from the same position. The color scale is the number of track found in each bin. The positive TY corresponds to tracks (muons) coming from the moun- tain direction, negative TY - muons comes from the back side (mainly from a free sky). The shadow of mountain is clearly visible for positive TY. The free sky muon flux was computed on the basis of the HKKM04 model [Honda et al. 2004] with a cut- off for energies below 1 GeV while in order to simulate the muon rates in the crater region we used the con- ventional cosmic ray flux attenuation values through the matter for each angle, and the digital elevation map (DEM) with 10 m resolution, kindly provided by the Italian Civil Defense. The DEM was also used to esti- mate the rock thickness shown in Figure 9d. On this an- gular plot the color scale for each bin presents the mean muon path (in meters) passed inside the rock before reaching the telescope. The parameters used for the simulation are: a uni- form rock density of 2.2 g/cm3, an exposure time of 154 days and an effective detector surface of about 0.6 m2. The mountain profile is well visible and its shape is well in agreement with the simulation. It is also possible to observe, in the plot of Figure 9c, showing the difference between Monte Carlo and data, a 10% excess of muon TIOUKOV ET AL. 4 Figure 6. Side view of a single module. Figure 7. Prototype of the European scanning system for emulsion data acquisition. Figure 8. Bidimensional histogram of the counted muons in the angular space distribution obtained on a partial statistics. 5 counting rates in the rock region (red circle labelled A) which seems to reveal the presence of a crater. On the other side, the muon flux in the free sky shows some discrepancies respect to the expected one; this effect has to be better investigated performing deeper studies on the detection efficiency as a function of track momen- tum, choosing appropriate selection criteria in order to keep low momentum background tracks under con- trol. Also a more precise Monte Carlo simulation taking into account the electromagnetic components of air showers and the cosmic muon scattering in the matter, should be provided. It is also necessary to consider the fact that the cosmic ray spectrum below 10 GeV is af- fected by not negligible uncertainties due to several fac- tors like geomagnetic latitude effects or solar modulation activity [Adriani et al. 2013]. At this stadium of the analysis it’s not yet possible to infer finest effects; any- way the preliminary comparison between Monte Carlo and data seems to be promising. 4. Conclusions and perspectives We described the muon radiography technique for imaging volcano structures, reporting the first prelim- inary results on the radiographic survey of Stromboli volcano with a nuclear emulsion telescope, obtained on the 60% of the collected statistics. A good match be- tween the mountain shape and Monte Carlo simulation has been observed, that means a good understanding both of detector position and the topographic map usage. Simulated and observed data seem to be in a good agreement, but a more refined analysis is manda- tory in order to better estimate the detection efficiency and background level for the final data interpretation. Actually the main background source as described in Nishiyama et al. [2014] is represented by low momen- tum tracks and one of the best tool to filter them is the usage of the Emulsion Cloud Chamber, OPERA-like that is made of interleaved layers of high-Z plates and emulsion plates. Muon radiography of volcanoes with nuclear emulsions seems to be very encouraging and motivates further research to improve the capability of the detector, the scanning power and the ability in in- terpretating data also from a geological point of view aiming a closer cooperation with geologists. Italian lab- oratories are involved in other projects as the Mt. Teide exposure (2012) under analysis and the recent exposure in La Palma (2014) to investigate the shape of the fault i.e. the depth, the width, and the porosity of the crush- ing zone. Nuclear emulsions are really suitable for muon radiography applications for several aspects already mentioned. The main drawback in using such detectors is the huge amount of scanning power required, but such difficulty is on the way to be solved. The nominal scanning speed of automatic microscopes is about 24 MUOGRAPHY WITH NUCLEAR EMULSIONS - STROMBOLI AND OTHER PROJECTS Figure 9. (a) Expected muon rates in 154 days on a detector surface of 0.6 m2; (b) observed muon rates; (c) difference normalized to the unit between Monte Carlo and data; (d) rock thickness. (a) (c) (d) (b) cm2/h/layer so the minimum time required for the full scanning of a Stromboli-like detector (1 m2 × 8 emul- sion layers) was about 170 days using the scanning power equivalent to 2 microscopes working at 30% of the time. Thanks to the recent software and HW upgrades the scanning speed increased up to 80 cm2/h/layer. This value could be further raised up to more than 200 cm2/h/layer. References Acquafredda, R., et al. (2009). The OPERA experiment in the CERN to Gran Sasso neutrino beam, J. In- strum., 4, P04018. Adriani, O., et al. (2013). Time dependence of the pro- ton flux measured by PAMELA during the July 2006-December 2009 solar minimum, Astrophys. J., 765, 91. Agafonova, N., et al. (2010). Observation of a first ox candidate in the OPERA experiment in the CNGS beam, Phys. Lett. B, 691, 138-145. Agafonova, N., et al. (2013). New results on on→ox ap- pearance with the OPERA experiment in the CNGS beam, J. High Energy Phys., 1311036. Agafonova, N., et al. (2014). Evidence for on→ox ap- pearance in the CNGS neutrino beam with the OPERA experiment, Phys. Rev. D., 89, 051102. Alexandrov, A. (2013). A novel approach for fast scan- ning of nuclear emulsions with continuous motion of the microscope stage, Conference Proceedings, Nucl. Instrum. Meth A, 718, 184-185. Arrabito, L., et al. (2006). Hardware performance of a scanning system for high speed analysis of nuclear emulsions, Nucl. Instrum. Meth. A, 568, 578-587. Arrabito, L., et al. (2007). Track reconstruction in the emulsion-lead target of the OPERA experiment using the ESS microscope, 2, P05004. Auger, E., L. D’Auria, M. Martini, B. Chouet and P. Dawson (2006). Realtime monitoring and massive inversion of source parameters of very long period seismic signals: An application to Stromboli Volcano, Geophys. Res. Lett., 33, L04301; doi:10.1029/2005 GL024703. Chouet, B., P. Dawson, T. Ohminato, M. Martini, G. Saccorotti, F. Giudicepietro, G. De Luca, G. Milana and R. Scarpa (2007). Source mechanisms of explo- sions at Stromboli Volcano determined from mo- ment-tensor inversions of very-longperiod data, J. Geophys. Res., 108 (B1), 2019; doi:10.1029/2002JB 001919. Gaisser, T. (1990). Cosmic Rays and Particle Physics, Cambridge University Press, New York. Honda, M., T. Kajita, K. Kasahara and S. Midorikawa (2004). New calculation of the atmospheric neutrino flux in a three-dimensional scheme, Phys. Rev. D, 70, 043008. Macedonio, G. (2009). Motivations for muon radiogra- phy of active volcanoes, Earth Planets Space, 61, 1-5. Nakamura, T., et al. (2006). The OPERA film: New nu- clear emulsion for large-scale, high-precision exper- iments, Nucl. Instrum. Meth. A, 556, 80-86. Nishiyama, R., S. Miyamoto and N. Naganawa (2014). Experimental study of source of background noise in muon radiography using emulsion film detectors, Geosci. Instrum. Meth., 3, 29-39. Tanaka, H.K.M., T. Nakano, S. Takahashi, J. Yoshida and K. Niwa (2007a). Development of an emulsion imaging system for cosmic-ray muon radiography to explore the internal structure of a volcano, Mt. Asama, Nucl. Instrum. Meth. A, 575, 489-497. Tanaka, H.K.M., T. Nakano, S. Takahashi, J. Yoshida, H. Ohshima, T. Maekawa, H. Watanabe and K. Niwa (2007b). Imaging the conduit size of the dome with cosmic ray muons: The structure beneath Showa Shinzan Lava Dome, Japan, Geophys. Res. Lett., 34, L22311. *Corresponding author: Valeri Tioukov, Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Napoli, Naples, Italy; email: valeri@na.infn.it. © 2017 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved. 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