Volcanoes in Italy and the role of muon radiography D'Alessandro, Raffaello; Ambrosino, F; Baccani, G ...
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
12/2018, Letnik:
377, Številka:
2137
Journal Article
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Cosmic-ray muon radiography (muography), an imaging technique that can provide measurements of rock densities within the top few 100 m of a volcanic cone, has now achieved a spatial resolution of the ...order of 10 m in optimal detection conditions. Muography provides images of the top region of a volcano edifice with a resolution that is considerably better than that typically achieved with other conventional methods (i.e. gravimetric). We expect such precise measurements, to provide us with information on anomalies in the rock density distribution, which can be affected by dense lava conduits, low-density magma supply paths or the compression with the depth of the overlying soil. The MUon RAdiography of VESuvius (MURAVES) project is now in its final phase of construction and deployment. Up to four muon hodoscopes, each with a surface of roughly 1 m
, will be installed on the slope of Vesuvius and take data for at least 12 months. We will use the muographic profiles, combined with data from gravimetric and seismic measurement campaigns, to determine the stratigraphy of the lava plug at the bottom of the Vesuvius crater, in order to infer potential eruption pathways. While the MURAVES project unfolds, others are using emulsion detectors on Stromboli to study the lava conduits at the top of the volcano. These measurements are ongoing: they have completed two measurement campaigns and are now performing the first data analysis.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.
We use observations of active fire area and fire radiative power (FRP) from the NASA Moderate Resolution Imaging Spectroradiometers (MODIS), together with a parameterized plume rise model, to ...estimate biomass burning injection heights during 2006. We use these injection heights in the GEOS-Chem (Goddard Earth Observing System Chemistry) atmospheric chemistry transport model to vertically distribute biomass burning emissions of carbon monoxide (CO) and to study the resulting atmospheric distribution. For 2006, we use over half a million FRP and fire area observations as input to the plume rise model. We find that convective heat fluxes and active fire area typically lie in the range of 1–100 kW m−2 and 0.001–100 ha, respectively, although in rare circumstances the convective heat flux can exceed 500 kW m−2. The resulting injection heights have a skewed probability distribution with approximately 80% of the injections remaining within the local boundary layer (BL), with occasional injection height exceeding 8 km. We do not find a strong correlation between the FRP-inferred surface convective heat flux and the resulting injection height, with environmental conditions often acting as a barrier to rapid vertical mixing even where the convective heat flux and active fire area are large. We also do not find a robust relationship between the underlying burnt vegetation type and the injection height. We find that CO columns calculated using the MODIS-inferred injection height (MODIS-INJ) are typically −9 to +6% different to the control calculation in which emissions are emitted into the BL, with differences typically largest over the point of emission. After applying MOPITT (Measurement of Pollution in the Troposphere) v5 scene-dependent averaging kernels we find that we are much less sensitive to our choice of injection height profile. The differences between the MOPITT and the model CO columns (max bias ~ 50%), due largely to uncertainties in emission inventories, are much larger than those introduced by the injection heights. We show that including a realistic diurnal variation in FRP (peaking in the afternoon) or accounting for subgrid-scale emission errors does not alter our main conclusions. Finally, we use a Bayesian maximum a posteriori approach constrained by MOPITT CO profiles to estimate the CO emissions but because of the inherent bias between model and MOPITT we find little impact on the resulting emission estimates. Studying the role of pyroconvection in the distribution of gases and particles in the atmosphere using global MOPITT CO observations (or any current spaceborne measurement of the atmosphere) is still associated with large errors, with the exception of a small subset of large fires and favourable environmental conditions, which will consequently lead to a bias in any analysis on a global scale.
We present the observation of a charge-sign dependent solar modulation of galactic cosmic rays (GCRs) with the Calorimetric Electron Telescope onboard the International Space Station over 6 yr, ...corresponding to the positive polarity of the solar magnetic field. The observed variation of proton count rate is consistent with the neutron monitor count rate, validating our methods for determining the proton count rate. It is observed by the Calorimetric Electron Telescope that both GCR electron and proton count rates at the same average rigidity vary in anticorrelation with the tilt angle of the heliospheric current sheet, while the amplitude of the variation is significantly larger in the electron count rate than in the proton count rate. We show that this observed charge-sign dependence is reproduced by a numerical “drift model” of the GCR transport in the heliosphere. This is a clear signature of the drift effect on the long-term solar modulation observed with a single detector.
Abstract Transmission muography is a non-invasive imaging technique that exploits the penetrating power of atmospheric muons into matter to obtain two-dimensional and three-dimensional density images ...of the monitored structure. The detectors used are particle trackers. Muography enables the monitoring of large structures and it is also particularly useful in the archaeological field for a mapping of low-density underground anomalies potentially related to unknown or inaccessible tombs or tunnels. The Palazzone necropolis, located south of Perugia (Italy), dating back to Etruscan period, contains about 200 known tombs, some of which, such as the Volumni Hypogeum, can be visited thanks to a touristic route. The eastern area of the necropolis, on the other hand, does not have a touristic path and is partially unknown. The objective of the muographic measurement campaign is to support the re-evaluation of this archaeological area by searching for new anthropic cavities and identifying them three-dimensionally. One of the goals of this study is to obtain a three-dimensional localization of cavities starting from a single muographic measurement by exploiting an image focusing algorithm. For this purpose, an area that contains a known cavity was used as the reference cavity for the test of the three-dimensional reconstruction algorithm.
Muon radiography is a technique based on the measurement of absorption profiles of muons as they pass through matter. This measurement allows to obtain an image of the inner structure of large volume ...objects and is suitable to be applied in several fields, such as volcanology, archaeology and civil engeneering. One of the main applications concerns the study of volcanic structures; indeed it is possible to use this technique to measure the mass distribution inside the edifice of a volcano providing useful information to better understand the possible eruption mechanisms. The MURAVES (MUon RAdiography of VESuvius) project aims to the study of the summital cone of Mt. Vesuvius near Naples in Italy, one of the most dangerous active volcanoes in the world. The MURAVES apparatus is a modular, robust muon hodoscope system with a low power consumption, optimized to be used in inhospitable environments like the surroundings of volcanoes. The complete detection system is an array of identical tracking modules, each with an area of 1 m2, based on the use of plasic scintillators. The technologies, the status and the data analysis strategy of the experiment will be presented in this paper.
Muon Radiography or muography is based on the measurement of the absorption or scattering of cosmic muons, as they pass through the interior of large scale bodies, In particular, absorption muography ...has been applied to investigate the presence of hidden cavities inside the pyramids or underground, as well as the interior of volcanoes’ edifices. The MURAVES project has the challenging aim of investigating the density distribution inside the summit of Mt. Vesuvius. The information, together with that coming from gravimetric measurements, is useful as input to models, to predict how an eruption may develop. The MURAVES apparatus is a robust and low power consumption muon telescope consisting of an array of three identical and independent muon trackers, which provide in a modular way a total sensitive area of three square meters. Each tracker consists of four doublets of planes of plastic scintillator bars with orthogonal orientation, optically coupled to Silicon photomultipliers for the readout of the signal. The muon telescope has been installed on the slope of the volcano and has collected a first set of data, which are being analyzed.
A novel algorithm developed within muon radiography to localize objects or cavities hidden inside large material volumes was recently proposed by some of the authors (Bonechi
2015
, P02003 ...(doi:10.1088/1748-0221/10/02/P02003)). The algorithm, based on muon back projection, helps to estimate the three-dimensional position and the transverse extension of detected objects without the need for measurements from different points of view, which would be required to make a triangulation. This algorithm can now be tested owing to the availability of real data collected both in laboratory tests and from real-world measurements. The methodology and some test results are presented in this paper.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.
Abstract
The BLEMAB European project (BLast furnace stack density Estimation through on-line Muon ABsorption measurements), evolution of the previous Mu-Blast European project, is designed to ...investigate in detail the capability of muon radiography techniques applied to the imaging of a blast furnace’s inner zone. In particular, the geometry and size of the so called “cohesive zone”, i.e. the spatial zone where the slowly downward moving material begins to soften and melt, that plays an important role in the performance of the blast furnace itself. Thanks to the high penetration power of the natural cosmic ray muon radiation, muon transmission radiography represents an appropriate non-invasive methodology for imaging large high-density structures such as blast furnaces, whose linear size can be up to a few tens of meters. A state-of-the-art muon tracking system, whose design profits from the long experience of our collaboration in this field, is currently under development and will be installed in 2022 at a blast furnace on the ArcelorMittal site in Bremen (Germany) for many months. Collected data will be exploited to monitor temporal variations of the average density distribution inside the furnace. Muon radiography results will also be compared with measurements obtained through an enhanced multipoint probe and standard blast furnace models.
The MIMA muon tracker, developed by the INFN Unit of Florence and the Department of Physics and Astronomy of the University of Florence, has been designed to test the application of muon radiography ...(or muography) to multidisciplinary case studies, to demonstrate its validity as an imaging tool in different fields and to develop dedicated data analysis strategies. The MIMA detector is a scaled-down version of the muon trackers developed for the “Mu-Ray” INFN R&D project and the MURAVES (MUon RAdiography of VESuvius) “Progetto Premiale”, financed by the Italian government. Thanks to its compactness, MIMA allowed the use of slightly different technical solutions with respect to the other detectors. Its construction was completed in the first half of 2017 and since then it has been used for several different measurements. In the second half of 2017 the detector was installed in the Bourbon Gallery inside Mount Echia, a hill in the center of Naples containing a complicated system of tunnels and cavities that have been dug over many centuries. The installation of the MIMA tracker was required to validate with an independent detector the results obtained in two previous measurements by the Mu-Ray tracker. After this measurement, the detector has been used in the Tuscany region, mainly for investigating two possible fields of application: geo-hydrological risk assessment and mining activity. The preliminary results of these tests and the future perspectives are shortly presented in this paper.
Coronal mass ejections (CMEs) cause the largest geomagnetic disturbances at Earth, which impact satellites, wired communication systems, and power grids. The CME Analysis Tool (CAT) is used to ...determine a CME's initial longitude, latitude, angular width, and radial speed from coronagraph images. These are the initial conditions for the Wang‐Sheeley‐Arge Enlil solar wind model, along with the ambient solar wind properties derived from magnetograms. However, the coronagraph imagery is limited by field of view. We have incorporated heliospheric imagery (HI) from the Solar Terrestrial Relations Observatory into CAT to create the CME Analysis Tool with Heliospheric Imagery (CAT‐HI). These HI images have a larger field of view, allowing tracking of CMEs to greater distances from the Sun. We have compared the performances of CAT and CAT‐HI by examining the expected arrival times of CMEs at the L1 Lagrange point and found them to be consistent. However, CAT‐HI is advantageous because it could be used to prune ensemble forecasts and issue routine updates for CME arrival time forecasts. Finally, we discuss CAT‐HI in the context of an operational mission at the L4 or L5 Lagrange points.
Plain Language Summary
Our Sun often releases large explosions of hot charged particles. These eruptions can travel through space all the way to the Earth. Here, they can damage satellites and disrupt communication systems and power grids. Therefore, we would like to predict their arrival time accurately, but currently, this is difficult. At the moment, operators use a tool based on coronagraph images, which look at the atmosphere of the Sun. This allows them to see the eruptions leaving the Sun. However, coronagraphs have a limited field of view, so the operators quickly lose sight of the eruptions. In this work, we have added a new kind of imagery that directly images the eruptions in the space between the Sun and the Earth. This new tool will allow the operators to track the eruptions for longer and to update their predictions of when they will arrive at Earth. The new tool could also be used in conjunction with a dedicated operational mission to monitor these eruptions. In summary, we think that the new tool presented in this paper could be a major advance in our ability to forecast these violent ejections.
Key Points
We developed a new CME analysis tool called CAT‐HI that incorporates Heliospheric Imagery from the STEREO spacecraft
CAT‐HI could enable ensemble pruning when running ensemble forecasts for CMEs and trajectory corrections
CAT‐HI could also be used in conjunction with a dedicated mission to L4 or L5
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