The presented work here focuses on electrical strength and electrical ageing tests performed on nanocomposite materials obtained by the dispersion of different ratio by weight of inorganic ...nanoparticles into a Low Density Polyethylene (LDPE) matrix. The experimental activity aims at investigating both the short term and the medium term properties of the obtained nanocomposites and to compare them with the behavior of the base polymer. The outcome evidences that the dispersion of a mixture of nanoparticles having different geometry and morphology, sepiolite and montmorillonite, could be an interesting approach in order to enhance the electrical properties of polymeric insulation.
A computer-aided detection (CAD) system for the selection of lung nodules in computer tomography (CT) images is presented. The system is based on region growing (RG) algorithms and a new active ...contour model (ACM), implementing a local convex hull, able to draw the correct contour of the lung parenchyma and to include the pleural nodules. The CAD consists of three steps: (1) the lung parenchymal volume is segmented by means of a RG algorithm; the pleural nodules are included through the new ACM technique; (2) a RG algorithm is iteratively applied to the previously segmented volume in order to detect the candidate nodules; (3) a double-threshold cut and a neural network are applied to reduce the false positives (FPs). After having set the parameters on a clinical CT, the system works on whole scans, without the need for any manual selection. The CT database was recorded at the Pisa center of the ITALUNG-CT trial, the first Italian randomized controlled trial for the screening of the lung cancer. The detection rate of the system is
88.5
%
with 6.6 FPs/CT on 15 CT scans (about 4700 sectional images) with 26 nodules: 15 internal and 11 pleural. A reduction to 2.47 FPs/CT is achieved at
80
%
efficiency.
The new trigger/GPS module for the EEE project Panetta, M.P.; Abbrescia, M.; Avanzini, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
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Odprti dostop
The Extreme Energy Events Project is an experiment devoted to the study of the Extensive Atmospheric Showers (EAS) which consists of a network of Multigap Resistive Plate Chambers (MRPCs) muon ...telescopes distributed over a very large area ∼3times105km2. It requires a precise time synchronization to correlate the information collected from each single detector. The data acquisition system of each telescope is equipped with a trigger unit and a GPS receiver to perform precision timing of events. The Global Positioning System (GPS) unit provides the one pulse per second signal (1PPS) which is used to create a timestamp in UTC time. A novel VME trigger unit for the EEE telescopes was developed, including an embedded GPS engine for timing application. The trigger/GPS unit is presented, including some preliminary measurements of its time resolution.
•The VME trigger unit includes an engine GPS to create the timestamp in UTC time.•The absolute time of an event is built by adding both the TDCs and the GPS data.•GPS unit provides the one pulse per second signal (1PPS) to synchronize the TDCs.•The time resolution measured for the 1PPS is less then ∼5 ns.
The whole Extreme Energy Events (EEE) array is composed of 61 telescopes installed in Italian High Schools, built and operated by students and teachers, constantly supervised by researchers. The muon ...telescope of the EEE Project is made by 3 Multigap Resistive Plate Chambers (MRPC). The unconventional working sites are a unique test field for checking the robustness and the low-ageing features of the MRPC technology for particle tracking and timing purposes. The MRPCs are fluxed with a standard mixture (98% C
2
H
2
F
4
- 2% SF
6
) of greenhouse gases (GHG) phasing out of production. The EEE Collaboration is currently studying alternative mixtures environmentally and economically sustainable. The EEE Collaboration actions to reduce the Global Warming Potential (GWP) in the MRPC array of the EEE experiment are progressing.
The Extreme Energy Events (EEE) experiment consists in a network of cosmic muon tracker telescopes, each made of three Multi-gap Resistive Plate Chambers (MRPC), able to precisely measure the ...absolute muon crossing time and the muon integrated angular flux at the ground level. To investigate the MRPC telescope response and performance, a simulation tool was developed in GEMC, software package based on GEANT4 libraries. The framework was validated by comparing simulations with the EEE experimental data. Detailed description of telescope response is fundamental to carry on the physics program of the EEE project, and it could open other research avenues, such as using the telescope in combination with other detectors to perform a (muon) tomography of material surrounding the telescope. In this paper, the EEE simulation framework will be presented reporting results and discussing further applications.
The Extreme Energy Events (EEE) experiment is a project by Centro Fermi (Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”) in collaboration with INFN, CERN and MIUR, designed to ...study cosmic rays via a network of muon telescopes, based on the Multigap Resistive Plate Chambers (MRPC) technology. Due to its wide coverage over the Italian territory (more than 10° in latitude and longitude, covering more than 3x105km2), the EEE network is the largest MRPC – based system for cosmic rays detection. Each MRPC has 6 gas gaps obtained by a stack of glass plate, spaced 250μm each, and is equipped with 24 copper strips. Since its beginning, the EEE MRPCs were filled with a gas mixture of 98% of tetrafluoroethane and 2% of sulfur hexafluoride, but recent restrictions on greenhouse gases have prompted the study of their performance with new gas mixtures. To this aim, extensive tests of tetrafluoropropene and carbon dioxide or sulfur hexafluoride gas mixtures have been carried out.
.
A search for long distance correlations between individual Extensive Air Showers (EAS) detected by pairs of MRPC telescopes of the Extreme Energy Events (EEE) network was carried out. The search ...for an anomaly in these events is the purpose of our work. A dataset obtained by all the possible 45 pairs between 10 EEE cluster sites (hosting at least two telescopes), located at relative distances between 86 and 1200km, was analyzed, corresponding to an overall period of 3968 days time exposure. To estimate the possible event excess with respect to the spurious rate, the number of coincidence events was extracted as a function of the time difference between the arrival of the showers in the two sites, from
±
10
s to the smallest time interval where events are still observed. The analysis was done taking into account both the time and orientation correlation between the showers detected by the telescope pairs. A few candidate events with unusually small time difference and angular distance were observed, with a p-value sensibly smaller than a confidence level of 0.05.
In this paper the first study of the upward going events detected by the telescopes of the Extreme Energy Event (EEE) project is reported. The EEE project consists of a detector array of Multigap ...Resistive Plate Chambers located at selected sites on the Italian territory. During autumn 2014 the first coordinated data taking period took place and around one billion candidate tracks were collected. Among them, of particular interest is the sample of particles which cross the telescopes from below. The results obtained demonstrate that the EEE telescopes can distinguish the electrons produced as decay products of cosmic muons stopped in the ground, or in the last chamber of the telescopes themselves, confirming the excellent performance of the system for the investigation of intriguing cosmic phenomena.
The new Trigger/GPS module for the extreme energy events project Abbrescia, M.; Avanzini, C.; Baek, Y. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2019, Letnik:
942
Journal Article
Recenzirano
Odprti dostop
The Extreme Energy Event (EEE) project is an experiment devoted to the study of high energy Extensive Air Showers (EAS) over a very large area, using an array of muon telescopes. At present the array ...is composed of more than 50 stations, most of them distributed across the Italian territory, on a total area of around 3×105km2. The telescopes are based on position-sensitive Multi-gap Resistive Plate Chambers (MRPCs) whose readout strips are connected to two TDC (Time-to-Digital Converter) units. Here a novel VME trigger unit for the EEE telescopes is presented, which also includes an embedded GPS receiver for precision timing applications. This new unit gets together, in the same electronic board, the functionalities of different parts of the electronics used up to now in the EEE experiment, and adds new ones, making the whole readout system simpler, more flexible and robust. Details about the trigger/GPS unit, including some measurements of its time resolution, are reported here.
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