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GI5.4

Open session on Muography

Muography, muon radiography, muon tomography - a loved child has many names. Muography is a novel particle-geophysical method taking the previously laboratory located ionizing particle detectors outdoors to observe density variations within geological, archaeological, civil engineering or national security applications. We welcome abstracts from technology and method developers and muography appliers.

Public information:

Muography, muon radiography, muon tomography - a loved child has many names.  Muography is a novel particle-geophysical method taking the previously laboratory located ionizing particle detectors outdoors to observe density variations within geological, archaeological, civil engineering or national security applications.  We welcome abstracts from technology and method developers and muography appliers.

Convener: Dezső Varga | Co-conveners: Marko HolmaECSECS, Jari JoutsenvaaraECSECS, Hiroyuki Tanaka
Presentations
| Thu, 26 May, 11:05–11:50 (CEST), 13:20–14:50 (CEST)
 
Room 0.51
Public information:

Muography, muon radiography, muon tomography - a loved child has many names.  Muography is a novel particle-geophysical method taking the previously laboratory located ionizing particle detectors outdoors to observe density variations within geological, archaeological, civil engineering or national security applications.  We welcome abstracts from technology and method developers and muography appliers.

Thu, 26 May, 10:20–11:50

Chairpersons: Dezső Varga, Jari Joutsenvaara

11:05–11:08
Muography introduction

11:08–11:10
Volcanology

11:10–11:20
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EGU22-9746
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solicited
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Highlight
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On-site presentation
Michael Tytgat and the MURAVES Collaboration

The MURAVES (Muon Radiography of VESuvius) muon telescope was conceived to study the internal structure of Mt. Vesuvius, an active volcano near Naples, Italy, using the absorption of muons generated by cosmic-ray showers in the upper atmosphere (a technique also known as “muography”). Even though the volcano is currently quiescent, this system presents a potential hazard for its highly populated surroundings. Muographical imaging data of the summit cone combined with gravimetric and seismic measurements may help the modeling of possible eruptive dynamics.

The MURAVES telescope currently consists of three identical, independent muon hodoscopes, each of them made of four 1m2 active area XY tracking stations and a 60cm thick lead wall placed in between the two downstream stations to passively reduce the background from low energy muons. The tracking stations are constructed using scintillator bars that are coupled via wave-length shifting fibers to silicon photomultipliers. The apparatus has been installed on Mt. Vesuvius and is currently acquiring data. Next to a description of the telescope setup, initial, preliminary results from the analysis of first data samples will be presented.

In addition, we will report on a number of simulation studies that allow us to investigate the effects of the experimental constraints and to compare our simulated data with the actual observations. The simulation chain is based on Geant4, and for the generation of cosmic showers a comparative study of particle generators, including CORSIKA and CRY, has been done to identify the most suitable one for our simulation framework. Muon transport through the mountain is being addressed using PUMAS and Geant4. We will present ongoing work on e.g. the detector digitization in the simulation, the muon track reconstruction and tracking inefficiencies, the effects of the lead wall, dark noise and other nuisances, and the simulation to measured data comparison.

How to cite: Tytgat, M. and the MURAVES Collaboration: Initial results of the MURAVES muon telescope at Mt. Vesuvius, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9746, https://doi.org/10.5194/egusphere-egu22-9746, 2022.

11:20–11:27
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EGU22-8616
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ECS
Assessing the rock density distribution of the La Soufrière de Guadeloupe volcano lava dome with a 4-panel scintillator-based muon detector
(withdrawn)
Raphaël Bajou et al.

11:27–11:29
Underground and geoscience

11:29–11:36
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EGU22-12174
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On-site presentation
Catherine Truffert et al.

A telescope based on scintillators technology has been installed at the footstep of giant cliffs for assessing massive rocks falls. Such an experience is a first in the “world of muography”. It was made possible thanks to the national geological service, the BRGM, in particular its regional branch based in Reunion Island. Muography was chosen because it allows to access the density variation in time and space, in a passive way, by collecting in the telescope the muons which crossed the rock. The telescope has been installed for up to 6 months at the footwall of the giant cliff.  The rainy season was chosen as the acquisition window to be able to follow the density variations that occur in the massif during rainy events.

The telescope is composed of 3 parallel ~1m2 active detection planes recording the positions and the precise time of the particles hits. The detector readout has been developed on the early concept of connected “smart sensors”. It allows an optimized selection of the particles hits to perform their tracking. A post-processing analysis will translate the recorded tracking properties into a detailed image of the target within the acceptance of the detector.

La Reunion Island, located East of Madagascar, is composed of three shield volcanoes among with la Fournaise which is still active. The volcanic cirques are subjected to large-scale rock-falls (>10,000 m3). 

On the top of the wall (or Rempart), the target of our muography experiment, the decompression cracks are concentrated on a strip often equivalent to 10% of the height of the cliff. The cliff can be higher than 1,000 m. These cracks, sometimes more than a meter wide, delimit the rock scales likely to be crumbled. The origin of these cracks, which are almost vertical on the surface, is linked to the natural decompression of the massif by the vacuum. The geometry of these cracks at depth is not well known, but it is likely that they acquire a slightly concave shape, bringing them closer to the wall and cutting out large scales at the crest of the Rempart. The volume of rock falling highly depends on the depth of these cracks.

Our experiment is focused on the Maïdo Rempart overlooking the western part of the Cirque of Mafate where the formations of the ancient volcanic outcrop in 1,000 m high scarps. We have installed a Muons telescope at “l’Ilet de Roche-Plate”, a small village located at the foot of active scree cones at the foot of the Maïdo Rempart. This innovative experiment follows a fire that occurred on the top of the Rempart at the end of 2020, which led to an increase in falling blocks and a potential acceleration in the opening of cracks. One of the issues is to better delimit the volume of "fractured" rocks and if possible, to identify the depth of the decompression cracks that delimit the scales likely to fall. 

How to cite: Truffert, C., bouteille, S., Marteau, J., Le Moigne, B., Huebert, N., and Samyn, K.: A telescope based on Scintillator technology for assessing massive rock falls – la reunion island, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12174, https://doi.org/10.5194/egusphere-egu22-12174, 2022.

11:36–11:43
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EGU22-3551
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Virtual presentation
Gergely Surányi et al.

Muography (or muon tomography) is one of the most effective methods for locating unknown density inhomogeneities, (eg. ore bodies or voids) underground. The geometric conditions have limitations, but otherwise there is no any other competing geophysical method, either the resolution or the simplicity is considered.

In the last years thanks to the continuous R&D in Wigner Research Centre for Physics, Budapest, we have been provided low-cost, portable muon detectors as well as newly-developed data processing methods. We have several ongoing natural and artificial cavity exploration projects and density inhomogeneity location projects for mining applications.

Here we present case studies carried on in Hungarian underground sites, where we could find unknown cavities and verify the method by locating known artificial shafts and adits with high precision. We have achieved that if the characteristic size of the void is only 2-3% of the rock thickness between the detector and the surface, the cavity location is feasible. To reach these unknown voids and density anomalies is in progress either by conventional caving exploration techniques or by drilling.

Further measurements are ongoing by the new upgraded detectors. By decreasing the gas consumption and supporting the electric power by solar cells, we are able to measure even at remote locations without the need of any direct access for several months duration.

How to cite: Surányi, G., Hamar, G., Nyitrai, G., and Gera, Á.: Application examples of underground muography, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3551, https://doi.org/10.5194/egusphere-egu22-3551, 2022.

11:43–11:50
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EGU22-6792
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Virtual presentation
Marko Holma et al.

Cosmic-ray muography is a novel methodology for monitoring and spatial imaging density variations in solid and liquid materials. It is based on the translation of the “raw” muon flux attenuation data to meaningful images that visualise the target’s bulk density radiographically (2D) or tomographically (3D). Both can also be applied as time-sequential mode allowing long-term monitoring of density-affecting processes. The core strength of muography is that it permits the observation of processes that change density and occur in timescales from hours to years. In geosciences, this may allow, for example, monitoring of glaciers, ground frost, movements of waters and fluids, propagation of fractures, and detection of faults. In the latter case, periodic drying may render a fault muographically visible during monitoring. Large faults can be imaged also directly. The already classic application of applying muography for long-term monitoring of active volcanoes allows detection of magma ascent and, therefore, early warnings of possible eruptions. In addition, muography can also be used for practical and industrial applications such as tunnelling, mining and geo- and civil engineering. In these cases, muography provides unique opportunities for long-term monitoring of activities and work safety.

The capabilities of muography are particularly fitting for studying bedrock fractures, weathering and the inner structure of different landforms that (a) comprise at least a few percentage differences between bulk densities of two or more rock or soil types (or their mixtures), (b) are located within the uppermost few hundreds of metres of crust, and (c) allow the installation of the muon detector(s) below or side of the volume of interest. Regarding the latter, detectors must be positioned between the open sky (the source of muons) and the volume of interest (object). In geomorphic research, appropriate settings for muography include the sides of mountains, hills, valleys, cliffs, gorges, glacigenic deposits, river terraces, caves, tunnels or boreholes. Many of the current muon detectors are mobile and robust, and due to self-sustainability, automation and remote access to data, they allow field measurements even in distant, rugged or harsh environments.

Our earlier research has demonstrated that the actual muography data can, for example, detect concealed faults and fractures, visualise and monitor groundwater table, reveal permeability barriers or zones of high porosity in soil and rock masses, image density anomalies in crystalline rocks, detect ascent of magma within an active volcano, and map out natural caves. Other researchers have demonstrated and proposed many other exciting applications in geoscience, archaeology, civil engineering, and many other fields of human activity. We suggest that muography provides extraordinarily fresh prospects for studies of the structure of many different types of landscape elements and monitoring and, perhaps, predicting their evolution [1]. The possibilities include research on soil erosion, subsurface fracturing and weathering, hillslope evolution, groundwater reservoirs, river channel erosion, drainage divides, glaciers, landslides, karst terranes and their aquifers, sinkholes, collapses, regoliths, saprolites, bauxites, soil geoengineering, and short- and long-term climate change.

[1] B. Ferdowsi et al., Earthcasting: Geomorphic Forecasts for Society, Earth’s Future 9, e2021EF002088. doi:10.1029/2021EF002088.

How to cite: Holma, M., Hall, A. M., Sarala, P., Putkinen, N., Tanaka, H. K. M., Oláh, L., and Kuusiniemi, P.: Muography as a Novel Field Observation Tool of Geomorphic Research, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6792, https://doi.org/10.5194/egusphere-egu22-6792, 2022.

Thu, 26 May, 13:20–14:50

Chairpersons: Dezső Varga, Jari Joutsenvaara

13:20–13:30
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EGU22-2793
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solicited
Gábor Nyitrai et al.

Muography is a novel imaging method, using muon particles present in cosmic rays at Earth surface level. These naturally occurring high energy muons are able to penetrate even kilometers of rock. The count rate (flux) depends on the zenith angle of the incoming muon, as well as on the density-length of the rock (density integrated along the muon path up to the detector) thus providing a powerful tool to image the average densities of 10-1000 m rock layers. In some cases with multiple detector locations, even 3D density reconstruction is possible. The geometric constraint of muography is that the altitude of the particle tracking detector must be lower than the examined object level.

Applications arise in multiple disciplinaries, including volcanology, mining, archeology, civil engineering, speleology. In this presentation the technology of muography will be reviewed, the muon detectors developed in Wigner RCP Budapest will be introduced, and experiences learned from ongoing projects will be presented. 

How to cite: Nyitrai, G., Hamar, G., and Surányi, G.: Overview of muography in geoscientific research, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2793, https://doi.org/10.5194/egusphere-egu22-2793, 2022.

13:30–13:37
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EGU22-8906
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Virtual presentation
Teemu Öhman et al.

Muography is used in, e.g., volcanology, archaeology, engineering and mineral exploration to characterise material densities [1–2]. To our knowledge, muography has not been applied for impact crater studies.

Muons are produced in the atmosphere as a by-product of particle reaction cascades commenced when high-energy cosmic-ray particles collide with air nuclei. Muons lose energy at a rate dependent on the density of the material. Muon counts are translated to density information and radiographic (2D), tomographic (3D), or time-lapse images. Joint inversion of muographic and gravity or seismic data is also possible [1,3].

Muon detectors are muon telescopes (MT) or downhole detectors (DD). The larger MTs “see” one direction at a time. DDs fit standard drill holes and “see” 360° but typically with a lower spatial resolution. They collect muon data from a conal volume of rocks.

Muography is energy-efficient and does not require radiation sources. In addition, muographic data are not affected by parameters other than density and, to a minor extent, chemistry. Also, the user has a lot of control for obtaining the required data quality and image resolution (e.g., more and/or larger detectors or longer surveys improve both parameters). This is a notable advantage over most other types of geophysical instruments.

The muon flux diminishes quickly with increasing depth. Hence, the deeper the detectors, the longer the surveys. In caves and mines below ~0.5 km, the measuring times have typically been months to years. However, this is not a severe challenge for impact structures, as most of them are shallow features and, consequently, the flux of muons has not yet been seriously diminished.

Every 1% difference in density provides an easily detectable ~3% difference in the muon flux. Granitoids have densities around 2600–2800 kgm-3, while mafic rocks can reach ~3000 kgm-3. In contrast, the densities of suevitic breccias vary substantially depending on the melt and clast contents, hydrothermal overprint, and weathering. They often have densities of ~2200–2300 kgm-3, while the densities of impact melt rocks tend to lie between those of target rocks and suevitic breccias. Fault breccias in crater rims and central uplifts can have densities ~100 kgm-3 lower than the surroundings.

A combination of MTs and DDs may provide the best results for impact structures. Topographic central peaks can be studied by both techniques. Crater fill materials and subdued central uplifts can be imaged via DDs. For preserved rims, it is best to use MTs on the crater floor or the terrace zone. The rims of shallow impact structures may be difficult for MTs, because only a few approximately horizontal muons bear information on the rim. In such a case, DDs can be applied much deeper, but the measurement may take longer. Overall, muography provides a cost-effective and more comprehensive 3D view of the crater than drill cores alone.

 

References: [1] Cosburn K. et al. (2019) Geophys. J. Int., 217, 1988–2002. [2] Zhang Z.-X. et al. (2020) Rock Mech. Rock Eng., 4893–4907. [3] Le Gonidec Y. et al. (2019) Sci. Rep., 3079.

How to cite: Öhman, T., Holma, M., and Kuusiniemi, P.: Studying Terrestrial Impact Structures With Cosmic-Ray Induced Atmospheric Muons, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8906, https://doi.org/10.5194/egusphere-egu22-8906, 2022.

13:37–13:39
Mining and industry

13:39–13:46
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EGU22-8837
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ECS
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Highlight
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Virtual presentation
Tommaso Beni et al.

In the last twenty years several applications of muography (or muon radiography) technique have been carried out for geological purposes. Among them, particular attention was given to underground ore bodies prospections. For thousands of years humans have been searching new methods to understand where to find underground ore bodies and how to localize it in the three-dimensional space. Often, economically useful minerals are bounded to other minerals, forming rocks of high density values that are hosted, usually, in rocks with lower density values. In literature gravimetry and magnetometry represent the most employed geophysical methods for imaging and detection of mineral-rich ore bodies. To verify the feasibility of muography as a non-invasive geophysical prospecting technique, our research group, composed by subnuclear physicists and geologists, carried out some underground measurement campaigns at the Temperino Mine (Campiglia Marittima, Italy). Here it is located a pliocenic metasomatic ore deposit, a Cu-Pb-Zn-Fe skarn complex composed by johannsenite, quartz, hedenbergite, ilvaite and accessory primary sulphides (chalcopyrite, galena, sphalerite, pyrite). These metalliferous bodies of skarn have tabular geometries with sub-vertical orientations. Currently, the first level of Temperino Mine has been equipped as a touristic path and belong to the Archeological Mining Park of San Silvestro. Along this gallery, carved both into the metamorphic and non-metamorphic rocks, it’s been installed the MIMA muon tracker (Muon Imaging for Mining and Archaeology), a small and rugged prototype (0.5 x 0.5. x 0.5 m3) developed by the physicists of the National Institute of Nuclear Physics (INFN), unit of Florence, and the Department of Physics and Astronomy of Florence. MIMA detector is able to measure the underground muon flux inside the mine gallery. Matching the simulated muon transmission rate with the experimentally measured one it’s possible to obtain a two dimensional average density angular map of the observed target. Also, using algorithms based on triangulation and back-projection techniques is possible to obtain a reconstruction of the 3D volume of high-density areas (and also low-density areas) inside the studied volume. The latter is the volume that falls within the detector’s acceptance. The aim of this research is to obtain a georeferenced 3D model of the Cu-Pb-Zn ore bodies hosted in the rocks between the top of the mine gallery and the surface of the Temperino Mine area. We want to confirm that muography technique could become a suitable and reliable tool for the mining prospections field.

How to cite: Beni, T., Baccani, G., Borselli, D., Bonechi, L., Bongi, M., Brocchini, D., Casagli, N., Ciaranfi, R., Cimmino, L., Ciulli, V., D'Alessandro, R., Del Ventisette, C., Dini, A., Gigli, G., Gonzi, S., Guideri, S., Lombardi, L., Mori, N., Nocentini, M., Noli, P., Saracino, G., and Viliani, L.: Absorption-based muography for ore bodies prospecting: a case study from Temperino Mine (Italy), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8837, https://doi.org/10.5194/egusphere-egu22-8837, 2022.

13:46–13:53
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EGU22-8808
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ECS
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Virtual presentation
Diletta Borselli et al.

Muon radiography is a non-invasive imaging technique that allows, through cosmic muon absorption measurements, to obtain two-dimensional and three-dimensional images of the internal structure and average density of very large material volumes. Its applications currently range from many fields: geological, archaeological, industrial, civil and nuclear safety. The technique of muon radiography being non-invasive represents a valid alternative to the common survey techniques in these fields of applications. In this presentation I will show some results obtained with this technique in the geological field for the three-dimensional imaging of cavities and tunnels within the Temperino mine located in the San Silvestro Archaeological Mining Park near Campiglia Marittima in the province of Livorno in Tuscany (Italy). The Temperino mine has ancient etruscan origins and still has areas which are not mapped in the available documentation. The mining activities of the area have always been focused on the search for a hard and dense rock called skarn in which there are metallic sulphides of Cu, Ag, Pb, Zn, Fe. Currently only one of the most superficial levels of the mine is accessible to the public through a tourist route. The muographic measurements on this site therefore have a dual objective, on the one hand to test the imaging technique on known cavities, on the other hand to discover new cavities whose knowledge could be useful, for example, for important assessments concerning historical and safety aspect of the site. All measurements were carried out with the muon detector MIMA (Muon Imaging for Mining and Archaeology) designed and built at the National Institute of Nuclear Physics (INFN) in Florence. MIMA is a cubic tracker of approximate dimensions (50x50x50) cm3and is equipped with a special protective aluminum mechanism that allows its altazimuth orientation. Various measurements were made within the tourist gallery located about 50 m below ground level for the observation of areas above. By comparing muon transmission measurements with simulations, it was possible to generate two-dimensional angular maps of average density of material observed in every direction within the detector's acceptance. The presence of some low-density anomalies associated with the presence of cavities was thus identified. Through algorithms based on the triangulation technique and on a track backprojection technique, the cavities were located in three-dimensions. For the known cavities it was also possible to compare the reconstructed development with their real profile that was acquired with the laser scanner technique, finding a good compatibility (average deviation below 1 m for a 7 m high cavity located 20 m above the detector’s installation location). These measurements therefore validate the muon radiography technique in the geological field for the search for cavities inside mines. The technique can be applied to identify not only low-density anomalies or voids, but also high-density areas: the application of the muon imaging technique for the identification of dense ore bodies is being studied at Temperino mine.

How to cite: Borselli, D., Baccani, G., Beni, T., Bonechi, L., Bongi, M., Brocchini, D., Casagli, N., Ciaranfi, R., Cimmino, L., Ciulli, V., D'Alessandro, R., Del Ventisette, C., Dini, A., Gigli, G., Gonzi, S., Guideri, S., Lombardi, L., Nocentini, M., Noli, P., Mori, N., Saracino, G., and Viliani, L.: Identification and three-dimensional localization of cavities at the Temperino mine (Tuscany-Italy) with the muon imaging technique , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8808, https://doi.org/10.5194/egusphere-egu22-8808, 2022.

13:53–14:00
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EGU22-10983
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ECS
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Virtual presentation
Mitro Juutinen et al.

Tailing sand is almost only gangue-minerals-containing mining waste formed during the ore enrichment process. This waste material is deposited as a slurry in tailings storage facilities. Waste rock is defined as a rock material removed around the ore and typically piled near the quarries and mines.

Back in the days when the ore processing methods were poorly developed and ore deposits were located just below the Earth’s surface, there were relatively large amounts of valuable materials left in the mining wastes. The heritage mining waste storage facilities, such as tailings ponds and waste rock stockpiles, are today considered significant secondary raw material resources by the EU. Moreover, due to the global trend of sustainable development and the EU’s vision of economic autonomy, especially those mining waste storage facilities that contain critical raw materials (such as battery metal-bearing minerals) are expected to play a significant role in the future. These factors drive exploration and beneficiation not only towards new ore deposits but also to the wastes of those deposits that were exploited in the past.

One of the methods that hold promise as a characterization method of heritage tailings and waste rocks in terms of the ore potential estimation is cosmic-ray muography. Muography is based on muons that are electron-like elementary particles formed by the collision of cosmic rays and substances of the atmosphere. All the time and everywhere on our planet, the surface of the Earth is bombarded by high-energy muons. Due to the high energy and the fact that a muon is much heavier than an electron, muons have a high penetrating power to dense materials. The idea of muography is to measure the attenuation of muons after they have travelled through the object and subsequently translate the recorded muon statistics into meaningful density information such as 2D or 3D images. As the highest-energy muons can pass through even kilometres of rock, muography can be applied in many applications within the uppermost kilometres or so of the Earth’s subsurface. The attenuation of muon flux depends on the mass density of the material: the denser the material is on average, the more it reduces the muon’s energy (muons that have lost enough energy become non-relativistic and rapidly cease to exist).

We tentatively propose that there is a major opportunity to utilize muography in the estimations of the ore potential of old mining waste facilities. For example, one application of muography could be the usage of a cylindrical detector placed in a borehole bored in a tailings pond.  The measurements could be made at different depths and with several detectors. The measurements could tell if there are density differences in tailings and how they are distributed. Muography could be a considerable method of targeting further estimation studies of the resource potential of the old tailings. Muography measurements could also be a possible way to target the exploration of old waste rock stockpiles. Such an endeavour could be carried out from the sides of the stockpiles with one or more muon telescopes.

How to cite: Juutinen, M., Holma, M., and Sarala, P.: Seeing through old mining wastes with secondary cosmic rays, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10983, https://doi.org/10.5194/egusphere-egu22-10983, 2022.

14:00–14:07
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EGU22-12554
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On-site presentation
Peter Filip and the NOvA Collaboration

Radiographic analysis of the overburden inhomogeneities above 
the NOvA Near Detector, located -100m below the surface at Fermilab, 
will be presented. A continuous measurement of the underground cosmic 
muon flux by the NOvA detector (of size 4x4x15 meters) allowed us to detect 
temporal variations of the overburden, related to the soil excavation and the concrete 
mass accumulation during the ICARUS detector installation at Fermilab. 
Utilising the internal reflection symmetries of the NOvA detector acceptance, we are
able to obtain a differential radiographic maps of the spatial overburden 
variations directly from the measured cosmic data, without using the Geant
simulations or the open-sky data subtraction.  

How to cite: Filip, P. and the NOvA Collaboration: Muographic Analysis of the NOvA-ND Cosmic Data, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12554, https://doi.org/10.5194/egusphere-egu22-12554, 2022.

14:07–14:14
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EGU22-2168
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ECS
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Highlight
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On-site presentation
László Oláh et al.

Muography is an imaging technique that can utilize cosmic-ray muons for remote and non destructive exploration of large-sized natural and human-made structures [1]. We applied mobile gaseous-detector-based muography instruments [2] for surveying different human-made structures in Japan:

(1) A buried reinforced concrete pillar (that is a standard pillar along Japanese railways) was installed inside a mound, and muography was blind tested from a three meter deep shaft located three meters away from the pillar [3]. Our muographic surveys revealed the bottom of the pillar at the depth of 80 cm with a spatial resolution of 15 cm within a few days.

(2) Debris dams are applied to prevent the catastrophic impacts of fast debris flows on the landscapes in mountain areas. We muographically measured the density-lengths through different debris dams (e.g., see in Ref. [4]) with a spatial resolution of below 50 cm within 2-4 weeks. The muographic surveys detected a weak zone inside a debris dam of Karasugawa river in consistency with elastic wave tomography survey.

(3) Muographic inspection of the Imashirozuka burial mound was conducted for detecting physical evidences related to a past earthquake [5]. This mound collapsed after a landslide generated by the 1596 Fushimi earthquake. Bidirectional muographic surveys detected a 4-8 m width low-density region at the top of the mound. These were interpreted as large-scale vertical cracks that caused the translational collapse process behind the rotational landslide that was already found in prior trench-survey-based works. The observations revealed that the mound already had intrinsic problem with the stability of the basic foundation before the earthquake.

These proof of concepts demonstrate the applicability of muography for geotechnical surveys and encourage the further studies for improving the protection of landscapes, economies and societies.

[1] Oláh, L., Tanaka, H. K. M., and Varga, D. Muography: Exploring Earth's Subsurface With Elementary Particles, 1st ed., Geophysical Monograph Series, Vol. 270, American Geophysical Union and John Wiley & Sons, ISBN 9781119723028, 2022.
[2] Oláh, L., et al.: CCC-based muon telescope for examination of natural caves, Geosci. Instrum. Method. Data Syst., 1, 229, https://doi.org/10.5194/gi-1-229-2012, 2012.
[3] Oláh, L., et al.: The first prototype of an MWPC-based borehole-detector and its application for muography of an underground pillar. Geophysical Exploration (J-STAGE), 71, 161-178, https://doi.org/10.3124/segj.71.161, 2018.
[4] Sakatani, Y., et al.: Research on the development of soundness analysis technology for Sabo-related infrastructure by muography (Part 1), Journal of the Japan Society of Erosion Control Engineering, ISSN 2433-0477, 85, 69, 2020. (In Japanese)
[5] Tanaka, H. K. M., Sumiya, K., and Oláh, L.: Muography as a new tool to study the historic earthquakes recorded in ancient burial mounds, Geosci. Instrum. Method. Data Syst., 9, 357, https://doi.org/10.5194/gi-9-357-2020, 2020.

How to cite: Oláh, L., Tanaka, H. K. M., Hamar, G., Miyamoto, S., Sakatani, Y., Mori, T., and Sumiya, K.: Muography as a novel complementary technique for geotechnical surveys , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2168, https://doi.org/10.5194/egusphere-egu22-2168, 2022.

14:14–14:16
Modeling and simulations

14:16–14:23
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EGU22-6285
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ECS
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Highlight
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Virtual presentation
Theodore Avgitas and Jacques Marteau

Muon tomography has witnessed significant growth during the last decade with volcanology being the main driving force behind this great success. Many sites around the world are currently studied and many new ideas concerning R&D, potential new targets and data analysis techniques are brought to light. Nevertheless, the potential for further developments is hindered by the lack of manpower to explore this changing landscape. Citizen science is the active involvement of the public in scientific research with the goal to further the domain’s knowledge. Citizen science projects has been developed during the last decade around experiments that produce high volume of data like ATLAS at CERN with the Higgs Hunters project and LIGO gravitational wave detector with Gravity Spy. This kind of projects has proved to build strong connections with a community of people that have an inner will for participation in scientific endeavors and muon tomography reaches fast that point where such a community could be proved valuable.  

Cosmic Muon Images is a muon tomography citizen science framework developed within the REsearch Infrastractures FOR Citizens in Europe (REINFORCE[1]) project (EU-funded, GA-822859). REINFORCE brings together four major scientific domains in order to engage citizen scientists in the process of scientific discovery. Muon tomography, Gravitational Waves, Neutrino Astronomy and High Energy Physics provide the ground for discussion and active involvement of people from all over the world with critical scientific issues like detection techniques, signal vs background rejection, environmental impact on measurement and many more. The goal of reaching the broadest possible audience would be disrupted if the data used by these projects were not accessible easily by as many people as possible. SonoUno[2] is a user centered software developed within REINFORCE that allows people with different sensory styles to explore scientific data, both visually and through sonorization.

Zooniverse[3] website hosts various citizen science projects, and a very active community has grown around it over many years. Cosmic Muon Images utilizes the website’s tools to develop workflows while at the same time communicate the science behind muon tomography so that people do their work more efficiently and consciously. Muon telescope data are visualized with 3D and 1D plots with the goal being the identification of patterns through a series of lines and points on these plots. This pattern identification results will be used to train Machine Learning (ML) algorithms to discriminate between signal and background events. Afterward we will evaluate the performance (speed, accuracy) of these ML algorithms in comparison to more traditional track reconstruction and event selection algorithms that are already in use. Furthermore, the classification of a dataset that people have cataloged by eye can prove to be extremely valuable so much for simulation development and background identification.

Muon Tomography provides a vast landscape of applications for citizen scientists to explore and projects that facilitate active participation can have mutual benefits for scientists and citizens alike, this is a first step towards this direction.


[1] https://www.reinforceeu.eu/

[2] http://sion.frm.utn.edu.ar/sonoUno/

[3] https://www.zooniverse.org/

 

How to cite: Avgitas, T. and Marteau, J.: Cosmic Muon Images: a muon tomography citizen science project, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6285, https://doi.org/10.5194/egusphere-egu22-6285, 2022.

14:23–14:30
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EGU22-1091
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ECS
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Virtual presentation
Roland Grinis et al.
Various industrial processes in geological formations, such as carbon dioxide capture sequestration, underground energy storage, enhanced oil recovery, hydraulic fracturing, well disposal, etc. could present safety and environmental risks including groundwater contamination. In the case of storage, any leaks would also be detrimental for the performance of the capture system. 
 
Non-aqueous phase liquids such as chlorinated hydrocarbons and oil, but also supercritical CO2 have low solubility in brine. Their migration, especially due to external forces, must be thoroughly monitored in order to avoid long-time pollution of freshwater aquifers in the subsurface. 
 
In our investigation, we will focus on geological carbon storage (GCS). Detecting breakthroughs in the carprock as early as possible is crucial to prevent further pollution of subsurface layers and assess storage exploitation. Still, we will keep the discussion general enough as the models we implement apply beyond GCS to all of the situations mentioned above. 
 
The use of atmospheric muons to monitor underground fluid saturation levels has been studied before. However, the low-contrast and possibly noisy muon flux measurements require accurate and realistic modeling of the main physical processes for the inverse problem behind monitoring. Moreover, first order sensitivity information for control parameters is needed to improve the analysis.
 
We address those issues in present work by incorporating a differentiable programming paradigm into the implementation of the detailed physics simulations in our set-up. The exposition is organised in the following manner. Firstly, we describe a model for the two-phase flow with capillary barrier effect in heterogeneous porous media for which we rely on the mixed-hybrid finite element method (MHFEM). Compared to previous studies, we develop a full 3D simulation and provide details for the implementation of adjoint sensitivity methods in the context of MHFEM. Secondly, we discuss muon transport building upon the Backward Monte-Carlo (BMC) scheme from V. Niess et al. (Comput. Phys. Comm. 2018). We re-use the spatial discretisation from MHFEM and perform sensitivity computations with respect to the media density and saturation levels following R. Grinis (arXiv:2108.10245 accepted to JETP 2021). Finally, we put everything together to design a system for detecting CO2 leakage through the caprock layer in GCS sites.

How to cite: Grinis, R., Palmin, V., Riazanov, D., and Kovalev, S.: Differentiable Model for Muon Transport and Two-Phase Flow in Porous Media with applications to Subsurface Pollution Monitoring, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1091, https://doi.org/10.5194/egusphere-egu22-1091, 2022.

14:30–14:37
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EGU22-4312
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ECS
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Virtual presentation
Amélie Cohu et al.

Muography is an imaging technique based on the differential absorption of a flux of incident particles, muons, by the target being studied. Muons are elementary particles that have the property to pass through standard rocks in a straight line to the first order, up to several kilometers away, and whose relative absorption allows to generate images by contrast densitometry, like a standard clinical X-ray. This technique infers the density of an object by tracking the number of muons received by a detector, before and after traversing a structure. The amount of density met by a muon on its path minimizes its survival probability in a predictable manner, hence diminising the average flux received by a detector. The incident direction (defined by the zenital angle) of the detected muons is reconstructed by means of a detector composed of a 3 scintillators panels, allowing to produce 2-D (or 3-D) density images.

To evaluate the degree of absorption caused by the density of structures, there are two key components: (1) the input flux (open-sky flux) which is infered theoretically, and (2) the output flux, measured by a detector. However, due to the diversity of possible observation conditions (altitude, longitude, latitude, solar winds, weather conditions, geomagnetic field...) of the open-sky flux, it is challenging to estimate it properly. The goal of this study is to improve the current way in which this estimate is done and apply it to the imaging of an industrial structure.

Two approaches are generally possible to estimate the open-sky flux. The first is based on semi-empiric models (Tang, Shukla, Gaisser ,etc...). The parameters of these formulae are calibrated using data sets. Analytical or empirical correction factors could be used to extrapolate these values to the desired survey elevation (z) and take into account the atmospheric conditions influence on muon production. The second approach makes use of CORSIKA, a Monte Carlo driven Nuclei-Hadron interaction model used for cosmic shower simulation. It has been used to simulate the influence of atmospheric conditions on the production and buffering of muons, as well as the effect of the geomagnetic field and the detector elevation. Both of these approaches have to overcome issues with extreme zenital angles.

Inter-comparision of analytical models, CORSIKA fluxes, and laboratory measurements are used as a means to validate our CORSIKA numerical experiment. Then, we analyzed the geodesic effects on the muon flux in terms of energetic composition with varying magnetic field, altitude and density distribution of the atmosphere. As a result, we have used our theoretical CORSIKA fluxes on an industrial application. We have studied the impact of the input flux in the opacity (quantity of matter crossed along a trajectory) estimate. First numerical results suggest that opacity estimate is strongly influenced in the 70 to 90° zenith angle region especially for low opacity targets.

How to cite: Cohu, A., Tramontini, M., Chevalier, A., Ianigro, J.-C., and Marteau, J.: Impact of Atmosphere fluctuations on Absorption Muon Tomography opacity estimates., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4312, https://doi.org/10.5194/egusphere-egu22-4312, 2022.

14:37–14:44
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EGU22-9470
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ECS
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On-site presentation
Maxime Lagrange et al.

 

We propose to employ differentiable programming techniques in order to construct a modular pipeline that models all the aspects of a muon tomography task, from the generation and interaction of cosmic ray muons with a parameterized detector and passive material, to the inference on the atomic number of the passive volume.

This enables the optimization of the detector parameters via gradient descent, to suggest optimal detector configurations, geometries, and specifications, subject to external constraints such as cost, detector size, and exposure time.

The eventual aim is to release the package open-source, to be used to guide the design of futur detectors for muon scattering and absorption imaging.

How to cite: Lagrange, M., Dorigo, T., Strong, G., Giammanco, A., Vischia, P., Fanzago, F., Nardi, F., and Lamparth, M.: TomOpt: Differentiable Muon-Tomography Optimization, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9470, https://doi.org/10.5194/egusphere-egu22-9470, 2022.

14:44–14:50
Discussion