Abstract
At Mount Etna volcano, the focus point of persistent tectonic extension is represented by the Summit Craters. A muographic telescope has been installed at the base of the North-East Crater ...from August 2017 to October 2019, with the specific aim to find time related variations in the density of volcanic edifice. The results are significant, since the elaborated images show the opening and evolution of different tectonic elements; in 2017, a cavity was detected months before the collapse of the crater floor and in 2018 a set of underground fractures was identified, at the tip of which, in June 2019, a new eruptive vent started its explosive activity, still going on (February, 2020). Although this is the pilot experiment of the project, the results confirm that muography could be a turning point in the comprehension of the plumbing system of the volcano and a fundamental step forward to do mid-term (weeks/months) predictions of eruptions. We are confident that an increment in the number of telescopes could lead to the realization of a monitoring system, which would keep under control the evolution of the internal dynamic of the uppermost section of the feeding system of an active volcano such as Mount Etna.
We have analyzed solar-like oscillations in ~1700 stars observed by the Kepler Mission, spanning from the main sequence to the red clump. Using evolutionary models, we test asteroseismic scaling ...relations for the frequency of maximum power ( Delta *nmax), the large frequency separation ( Delta *D Delta *n), and oscillation amplitudes. We show that the difference of the Delta *D Delta *n- Delta *nmax relation for unevolved and evolved stars can be explained by different distributions in effective temperature and stellar mass, in agreement with what is expected from scaling relations. For oscillation amplitudes, we show that neither (L/M) s scaling nor the revised scaling relation by Kjeldsen & Bedding is accurate for red-giant stars, and demonstrate that a revised scaling relation with a separate luminosity-mass dependence can be used to calculate amplitudes from the main sequence to red giants to a precision of ~25%. The residuals show an offset particularly for unevolved stars, suggesting that an additional physical dependency is necessary to fully reproduce the observed amplitudes. We investigate correlations between amplitudes and stellar activity, and find evidence that the effect of amplitude suppression is most pronounced for subgiant stars. Finally, we test the location of the cool edge of the instability strip in the Hertzsprung-Russell diagram using solar-like oscillations and find the detections in the hottest stars compatible with a domain of hybrid stochastically excited and opacity driven pulsation.
The Muon Portal Project has built a prototype of a real size detector (6m×3m×7 m) for the inspection of containers by muon tomography. This technique may provide 2D and 3D images of the interior of a ...container, to identify the presence of high-Z materials. In the present Project, 4800 extruded scintillator strips were arranged such as to cover four X–Y detection planes (6m×3 m), two placed above and two below the container to be inspected. Silicon photomultipliers were used as photosensors, to collect the light transported by Wave Length Shifter (WLS) fibres embedded in the scintillator strips. First tomographic images are here presented.
The MEV project aims at developing a muon telescope expressly designed for the muography of Etna Volcano. In particular, one of the active craters in the summit area of the volcano would be a ...suitable target for this experiment. A muon tracking telescope with high imaging resolution was built and tested during 2017. The telescope is a tracker based on extruded scintillating bars with WLS fibers and featuring an innovative read-out architecture. It is composed of 3×1m2 XY planes; the angular resolution does not exceeds 0.4msr and the total angular aperture is about ±45∘. A special effort concerned the design of mechanics and electronics in order to meet the requirements of a detector capable to work in a hostile environment such as the top of a tall volcano, at a far distance from any facility. The test phase started in January 2017 and ended successfully at the end of July 2017. An extinct volcanic crater (the Monti Rossi, in the village of Nicolosi, about 15 km from Catania) was the target of the measurement. The detector acquired data for about 120 days and the preliminary results are reported in this work.
Cosmic ray tomography is a technique which exploits the multiple Coulomb scattering of highly penetrating cosmic ray-produced muons to perform non-destructive inspection of high-Z materials without ...the use of artificial radiation. A muon tomography detection system can be used as a portal monitor at border crossing points for detecting illegal targeted objects. The Muon Portal Project is a joint initiative between Italian research and industrial partners, aimed at the construction of a real size detector prototype (6×3×7m3) for the inspection of cargo containers by the muon scattering technique. The detector consists of four XY tracking planes, two placed above and two below the container to be inspected. After a research and development phase, which led to the choice and test of the individual components, the construction and installation of the detection modules is almost completed. In this paper the present status of the Project is reported, focusing on the design and construction phase, as well as on the preliminary results obtained with the first detection planes.
Highlights • High resolution imaging: high spatial resolution (up to 150 μm), high resolution residual range measurement (up to 150 μm). • Large sensitive area attainable (up to 40 × 40 cm2 ). • ...Smart read-out strategy for real time imaging and residual range measurement at high resolution. • High rate beam compliance. • Sensitive area realized by scintillating fibers, water equivalence.
Experimental results from a dataset collected with a full-scale muon tomograph for the inspection of cargo containers were studied in a single scattering scenario with a multiparametric analysis ...based on the method of the Point Of Closest Approach (Poca). To search for high-Z materials, a 4
dm
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Pb block was positioned inside the volume to be inspected, in order to quantitatively investigate the appearance of the Poca signal. Signal-to-noise ratio and significance of the Poca signal were investigated by means of mono-dimensional spectra of the Poca components, for different values of the scattering angle between the incoming and outgoing muon tracks and with different angle-dependent weights. A systematic scan of two-dimensional maps was also carried out, as a strategy to search for possible enhancements to the Poca signal. A comparison was also done between the results obtained from the two half-volumes, one containing the Pb block and one left empty, to take into account the response of the detector and some aspects of the Poca strategy.
In this contribution, we will illustrate the main results of the R&D activities related to the Silicon Carbide detectors associated with NUMEN project.
The MEV project is running for a long-term muography measurement at the North-East crater of the Etna Volcano, after the successful conclusion of the test phase in July 2017. Two sets of data were ...already acquired during 2017, during the last months of the summer, and 2018. Data analysis is currently ongoing in order to extract a two-dimensional density map of the target from the measured muon flux. But before, a major improvement on data pre-processing was required. It regards in particular the algorithm for event reconstruction and filtering and the introduction of a method to extract the telescope efficiency from data themselves. The main steps of this pre-analysis and their application to the test data set is described in this paper.
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