arXiv subjects

Jacques Marteau

Publications and source records attributed to Jacques Marteau.

14 recordsLinked to original sources

arXiv2024

Ground water retention correlation to atmospheric muon rates

Muography is an investigation technique based on the detection of the atmospheric muon flux' modification through matter. It has found lately multiple applications in geosciences, archaelogy, and non invasive industrial controls. Mostly known for its imaging capabilities, muography may be exploited as well for monitoring purposes since the atmospheric muon flux is available permanently. In this paper we present an interesting measurement performed in the context of an archaelogical project called Arch\'emuons, on the archaeological site of "Palais du Miroir" in Vienne, South of Lyon, France. We installed a muon detector in an underground gallery within the foundations of the building for the second half of 2023. The primary goal is to measure details of those foundations which are largely not excavated yet. Meanwhile we observed over more than 6 months long-term and short-term variations of the muon rates since the start of the experiment, which seem to exhibit a correlation with the rain accumulating on the free field just above the gallery. We propose as an explanation for this behavior the retention of water by the soil above the detector site.

physics.geo-ph↗

arXiv2024

Prototype Cherenkov Detector Characterization for Muon Tomography Applications

Muography is an innovative imaging technique using naturally produced elementary particles -- atmospheric muons -- like the X-rays of medical imaging. The modification of the particles flux -- by scattering or absorption --, reflects the contrasts in density within the medium and therefore offers the possibility for an image of the crossed volumes. The imaging process is based on the tracking of the particles which accounts for the absorption or the scattering of the muons trajectories. Neither the energy nor the identity of the particles (the so-called PID) is exploited since this information traditionally relies on the use of calorimeters and/or high intensity magnetic fields. Both these techniques hinder detector portability which in the case of muography is important and this renders them impractical for its purpose. In this paper we characterize the performance of a simple and small water Cherenkov detector capable on the one hand of providing some insights on energy and PID and on the other hand of improving the background rejection for a muon telescope. We tested a prototype of such water Cherenkov detector in combination with two small muon hodoscopes. Both systems are using the same opto-electronics chain -- optical fibers and pixellized photosensors -- and the same data acquisition (DAQ) readout system which ensures an easy integration and implementation within presently running systems. This article presents the test setup, the detector response to cosmic muons and its performance evaluation against a basic simulation of its geometry and detection principle.

physics.ins-det↗

arXiv2023

Paarl Africa Underground Laboratory (PAUL)

Establishing a deep underground physics laboratory to study, amongst others, double beta decay, geoneutrinos, reactor neutrinos and dark matter has been discussed for more than a decade within the austral African physicists' community. PAUL, the Paarl Africa Underground Laboratory, is an initiative foreseeing an open international laboratory devoted to the development of competitive science in the austral region. It has the advantage that the location, the Huguenot tunnel, exists already and the geology and the environment of the site is appropriate for an experimental facility. The paper describes the PAUL initiative, presents the physics prospects and discusses the capacity for building the future experimental facility.

hep-ex↗

arXiv2023

First 3D reconstruction of a blast furnace using muography

The blast furnace (BF) is the fundamental tool used in the iron manufacture. Due to the difficulty of accessing direct measurements of the inner phenomena, we determined the density distribution of its internal volume in order to improve its productivity using muography. This is an imaging technique based on the differential absorption of a flux of incident particles, muons, by the target under study, similar to clinical X-ray imaging. Muons are elementary particles that have the property of passing through dense materials, up to hundreds of meters away. Their relative absorption and deviation allows the generation of density distribution images of an object by tracking the number of muons received by a detector, before and after passing through a structure. The incident direction of the detected muons is reconstructed by means of a detector composed of 3 scintillator panels that we moved on 3 positions around the BF. With this technique, we obtained the first 3D image of the internal structure of a BF using a Markov Chain Monte Carlo (MCMC) inverse problem solving algorithm on muon flux data. We were also able to perform a density monitoring of the BF and some of its operating parameters. We distinguished the position and shape of the cohesive zone, a key element in the productivity of a furnace, validating this innovative measurement concept in the application to a BF and opening the field to a series of future experiments to gain both spatial and temporal resolution.

physics.geo-ph↗

arXiv2022

Muography applied to archaelogy

A tomography experiment using muon cosmic rays was conducted on an archaeological site in Greece, a tumulus. This contribution presents issues related to the simulation of the experiment and of the site, using tools commonly used in high-energy physics. The scientific objective is to compare the results of the simulation with the recorded data to highlight anomalies.

physics.geo-ph↗

arXiv2022

A new versatile method for the reconstruction of scintillator-based muon telescope events

This paper presents a new method to process the data recorded with muon telescopes. We have developed this processing method for the plastic scintillator-based hodoscopes located around the volcano La Soufrière de Guadeloupe, in the French Lesser Antilles, in order to perform muon radiographies of the lava dome region, strongly impacted by the volcanic hydrothermal activity. Our method relies on particle trajectory reconstruction, performing a fit of the recorded hits in the impacted scintillator bars using a Random Sample Consensus algorithm. This algorithm is specifically built to discriminate outlier points, usually due to noise hits, in the data. Thus, it is expected to significantly improve the signal/noise separation in muon track hits and to obtain higher quality estimates of the particles' incident trajectories in our detectors. The first analysis of the RANSAC-reconstructed events offers promising results in terms of average density maps. To illustrate the performances of this algorithm, we provide angular resolution and reconstruction efficiency estimates using a GEANT4 simulation of a telescope equipped with four detection matrices. In addition, we also show preliminary results from open-sky data recorded with such telescope at La Soufrière de Guadeloupe volcano.

physics.geo-ph↗

arXiv2022

Atmospheric & geodesic controls on muon rate: a numerical study based on Corsika

Muon rate models play a key role in converting measured data into information on the density distributions of a target. Any given muography measurement, either in transmission or in scattering mode, requires a proper modelization of the muon flux according to the localization and to the atmospheric conditions. Two approaches are commonly used: either through semi-empirical models calibrated on existing data or via Monte-Carlo simulations. The former requires extrapolations to the field experiment conditions while the latter offers the advantage of tackling down in an unique way all relevant parameters such as barometric conditions, geomagnetic field, atmosphere density etc. Although significant progress were made in the last decades, precision muography experiments require more and more accuracy on the models, especially for the muons close to the horizon where large disparities still remain. In this paper we present detailed results obtained with the CORSIKA simulation framework to emphasize and quantify the impact of the environmental conditions on the sensitivity of muography measurements.

physics.geo-ph↗

arXiv2019

Middle-atmosphere dynamics observed with a portable muon detector

In the past years, large particle-physics experiments have shown that muon rate variations detected in underground laboratories are sensitive to regional, middle-atmosphere temperature variations. Potential applications include tracking short-term atmosphere dynamics, such as Sudden Stratospheric Warmings. We report here that such sensitivity is not only limited to large surface detectors under high-opacity conditions. We use a portable muon detector conceived for muon tomography for geophysical applications and we study muon rate variations observed over one year of measurements at the Mont Terri Underground Rock Laboratory, Switzerland (opacity of ~700 meter water equivalent). We observe a direct correlation between middle-atmosphere seasonal temperature variations and muon rate. Muon rate variations are also sensitive to the abnormal atmosphere heating in January-February 2017, associated to a Sudden Stratospheric Warming. Estimates of the effective temperature coefficient for our particular case agree with theoretical models and with those calculated from large neutrino experiments under comparable conditions. Thus, portable muon detectors may be useful to 1) study seasonal and short-term middle atmosphere dynamics, especially in locations where data is lacking such as mid-latitudes; and 2) improve the calibration of the effective temperature coefficient for different opacity conditions. Furthermore, we highlight the importance of assessing the impact of temperature on muon rate variations when considering geophysical applications. Depending on latitude and opacity conditions, this effect may be large enough to hide subsurface density variations due to changes in groundwater content, and should therefore be removed from the time-series.

physics.geo-ph↗

arXiv2017

Three-dimensional density structure of La Soufrieère de Guadeloupe lava dome from simultaneous muon radiographies and gravity data

Muon imaging has recently emerged as a powerful method to complement standard geophysical tools in the understanding of the Earth's subsurface. Muon measurements can yield a radiography of the average density along the muon path, allowing to image large volumes of a geological body from a single observation point. Here we jointly invert muon data from three simultaneous telescope acquisitions together with gravity data to estimate the three-dimensional density structure of the La Soufrière de Guadeloupe lava Dome. Our unique dataset allows us to achieve an unprecedented spatial resolution with this novel technique. The retrieved density model reveals an extensive, low-density anomaly where the most active part of the volcanic hydrothermal system is located, supporting previous studies that indicate this region as the most likely to be involved in a partial edifice collapse.

physics.geo-ph↗

arXiv2016

DIAPHANE: Muon tomography applied to volcanoes, civil engineering, archaelogy

Muography techniques applied to geological structures greatly improved in the past ten years. Recent applications demonstrate the interest of the method not only to perform structural imaging but also to monitor the dynamics of inner movements like magma ascent inside volcanoes or density variations in hydrothermal systems. Muography time-resolution has been studied thanks to dedicated experiments, e.g. in a water tower tank. This paper presents the activities of the DIAPHANE collaboration between particle- and geo-physicists and the most recent results obtained in the field of volcanology, with a focus on the main target, the Soufrière of Guadeloupe active volcano. Special emphasis is given on the monitoring of the dome's inner volumes opacity variations, that could be inferred to the hydrothermal system dynamics (vaporization of inner liquid water in coincidence with the appearance of new fumaroles at the summit). I also breifly present results obtained in the fields of civil engineering (study of urban underground tunnels) and archaelogy (greek tumulus scanning).

physics.geo-ph↗

arXiv2016

Muon dynamic radiography of density changes induced by hydrothermal activity at the La Soufrière of Guadeloupe volcano

Imaging geological structures through cosmic muon radiography is a newly developed technique particularly interesting in volcanology. Here we show that muon radiography may be efficient to detect and characterize mass movements in shallow hydrothermal systems of low-energy active volcanoes like the La Soufrière lava dome. We present an experiment conducted on this volcano during the Summer $2014$ and bring evidence that huge density changes occurred in three domains of the lava dome. Depending on their position and on the medium porosity the volumes of these domains vary from $1 \times 10^6 \; \mathrm{m}^3$ to $7 \times 10^6 \; \mathrm{m}^3$. However, the mass changes remain quite constant, two of them being negative ($Δm \approx -0.6 \times 10^9 \; \mathrm{kg}$) and a third one being positive ($Δm \approx +2 \times 10^9 \; \mathrm{kg}$). We attribute the negative mass changes to the formation of steam in shallow hydrothermal reservoir previously partly filled with liquid water. This coincides with the apparition of new fumaroles on top of the volcano. The positive mass change is synchronized with the negative mass changes indicating that liquid water probably flowed from the two reservoirs invaded by steam toward the third reservoir.

physics.geo-ph↗

arXiv2016

Monitoring temporal opacity fluctuations of large structures with muon tomography : a calibration experiment using a water tower tank

Usage of secondary cosmic muons to image the geological structures density distribution significantly developed during the past ten years. Recent applications demonstrate the method interest to monitor magma ascent and volcanic gas movements inside volcanoes. Muon radiography could be used to monitor density variations in aquifers and the critical zone in the near surface. However, the time resolution achievable by muon radiography monitoring remains poorly studied. It is biased by fluctuation sources exterior to the target, and statistically affected by the limited number of particles detected during the experiment. The present study documents these two issues within a simple and well constrained experimental context: a water tower. We use the data to discuss the influence of atmospheric variability that perturbs the signal, and propose correction formulas to extract the muon flux variations related to the water level changes. Statistical developments establish the feasibility domain of muon radiography monitoring as a function of target thickness (i.e. opacity). Objects with a thickness comprised between $\simeq$ 50 $\pm$ 30m water equivalent correspond to the best time resolution. Thinner objects have a degraded time resolution that strongly depends on the zenith angle, whereas thicker objects (like volcanoes) time resolution does not.

physics.ins-det↗

arXiv2015

Muon tomography applied to active volcanoes

Muon tomography is a generic imaging method using the differential absorption of cosmic muons by matter. The measured contrast in the muons flux reflects the matter density contrast as it does in conventional medical imaging. The applications to volcanology present may advantadges induced by the features of the target itself: limited access to dangerous zones, impossible use of standard boreholes information, harsh environmental conditions etc. The Diaphane project is one of the largest and leading collaboration in the field and the present article summarizes recent results collected on the Lesser Antilles, with a special emphasis on the Soufrière of Guadeloupe.

physics.ins-det↗

arXiv2014

Joint inversion of muon tomography and gravimetry - a resolving kernel approach

Both muon tomography and gravimetry are geophysical methods that provide information on the density structure of the Earth's subsurface. Muon tomography measures the natural flux of cosmic muons and its attenuation produced by the screening effect of the rock mass to image. Gravimetry generally consists in measurements of the vertical component of the local gravity field. Both methods are linearly linked to density, but their spatial sensitivity is very different. Muon tomography essentially works like medical X-ray scan and integrates density information along elongated narrow conical volumes while gravimetry measurements are linked to density by a 3-dimensional integral encompassing the whole studied domain. We develop the mathematical expressions of these integration formulas -- called acquisition kernels -- to express resolving kernels that act as spatial filters relating the true unknown density structure to the density distribution actually recoverable from the available data. The resolving kernels provide a tool to quantitatively describe the resolution of the density models and to evaluate the resolution improvement expected by adding new data in the inversion. The resolving kernels derived in the joined muon/gravimetry case indicate that gravity data are almost useless to constrain the density structure in regions sampled by more than two muon tomography acquisitions. Interestingly the resolution in deeper regions not sampled by muon tomography is significantly improved by joining the two techniques. Examples taken from field experiments performed on La Soufrière of Guadeloupe volcano are discussed.

physics.geo-ph↗