199 research outputs found

    Electro-optical cable and power feeding system for the NEMO Phase-2 project

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    Abstract The "NEMO Phase-2" project consists of a new facility placed on the sea floor at 3500 m depth, 40 nautical miles southeast of the south coast of Sicily. Technical aspects of the facility under realization are presented with particular attention to the electro-optical cable, the on-shore and deep-sea power transmission system, the control system and the connection system

    Sensitivity and pointing accuracy of the NEMO km3 telescope

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    In this paper we present the results of Monte Carlo simulation studies on the capability of the proposed NEMO km3 telescope to detect high-energy neutrinos. We calculated the detector sensitivity to muon neutrinos coming from a generic point-like source. We also simulated the lack of atmospheric muons in correspondence to the Moon disk in order to determine the detector angular resolution and to check the absolute pointing capability

    Scalable TriDAS for the NEMO project

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    Abstract The data acquisition for the NEMO km 3 detector is based on the all data to shore approach. The continuous data stream, coming from more than 8000 PMTs, will be greater than 32 GBps, and therefore it requires a fast on-line filtering for an appropriate noise suppression. An on-shore multi-system Trigger Infrastructure has been studied to handle and real-time analyze such an amount of data. In order to accomplish the data acquisition of the NEMO prototype tower, expandable algorithms and services for data handling, system control and monitoring have been prepared

    Status of NEMO

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    The activities towards the realization of an underwater km3 Cerenkov neutrino detector carried out by the NEMO Collaboration are described. Long term exploration of a 3500 m deep sea site close to the Sicilian coast has shown that it is optimal for the installation of the detector. The realization of a Phase-1 project, which is under way, will validate the proposed technologies for the realization of the km3 detector on a Test Site at 2000 m depth. The realization of a new infrastructure on the candidate site (Phase-2 project) will provide the possibility to test detector components at 3500 m depth

    Neutrino astrophysics with the ANTARES Cherenkov Detector

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    The ANTARES neutrino telescope is currently the largest water Cherenkov detector in operation in the Northern Hemisphere. The detector is a lattice of 885 Optical Modules distributed over 12 lines, located 40 km off the Southern French coast at a depth of about 2500 m. Its main scientific goal is the detection of high energy cosmic neutrinos from galactic and extra galactic sources using the Cherenkov photons emitted along the pattern of neutrino-induced charged leptons. The detector has been taking data regularly since 2006 in a partial configuration and has been completed in Spring 2008. The status of the experiment is reported and a selection of the latest results is discussed. In particular, this paper presents the up to date upper limits for diffuse high-energy cosmic neutrino flux, the searches for point sources, the multi-messenger analyses and the measurement of the neutrino oscillations

    The system to mitigate sediment deposition in the upper surface of the Digital Optical Module in KM3NeT: Part II

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    The experiments ANTARES and NEMO have shown the accumulation of a thin layer of material in the upper surface of the Optical Modules (OMs). The proposed vibration system to remove this sedimentation from the DOMs surface was tested successfully in a water tank at atmospheric pressure (see [2]). In this note we describe the behaviour of the system in an hyperbaric chamber at a pressure of 360 bar, close to the operating conditions in the sea. We find that the effect of the pressure does not significantly affect the vibration intensity in the glass spher

    A preliminary snapshot investigation of the marine soundscape for Malta : a stepping stone towards achieving ‘good ecological status’

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    The ever-accelerating rate of research focusing on the issue of underwater noise pollution, particularly concerning low-frequency, continuous noise, has steadily been unveiling the myriad of detrimental ecological implications caused to marine life. Despite this, many European Member States, such as Malta, still lack solid monitoring and regulatory frameworks aimed at characterising and improving the state of the marine acoustic environment and achieving ‘Good Ecological Status’ in accordance with the Marine Strategy Framework Directive. This shortcoming is directly reflected in the complete absence of baseline information covering the quality of the national soundscape. This paper aims to serve as a preliminary investigation into continuous underwater noise generation within Maltese waters, focusing on two sites characterised by heavy marine activity: Cirkewwa and the Grand Harbour. Digital signal processing software packages (dBWav version 1.3.4) were used to extract and analyse sound pressure levels from in situ recorded audio files. Further statistical analysis was also carried out so as to evaluate the resultant snapshot of the baseline marine soundscapes at both sites. Furthermore, AIS data were used to tentatively identify the identifiable sources of underwater noise pollution. Given the current information lacuna revolving around the issue of underwater noise pollution in Malta, this paper may serve as a pilot study, with the aim of bridging this knowledge gap and forming the basis of future national research for Maltese marine conservation.peer-reviewe

    Implementation and first results of the KM3NeT real-time core-collapse supernova neutrino search

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    The KM3NeT research infrastructure is under construction in the Mediterranean Sea. KM3NeT will study atmospheric and astrophysical neutrinos with two multi-purpose neutrino detectors, ARCA and ORCA, primarily aimed at GeV–PeV neutrinos. Thanks to the multi-photomultiplier tube design of the digital optical modules, KM3NeT is capable of detecting the neutrino burst from a Galactic or near-Galactic core-collapse supernova. This potential is already exploitable with the first detection units deployed in the sea. This paper describes the real-time implementation of the supernova neutrino search, operating on the two KM3NeT detectors since the first months of 2019. A quasi-online astronomy analysis is introduced to study the time profile of the detected neutrinos for especially significant events. The mechanism of generation and distribution of alerts, as well as the integration into the SNEWS and SNEWS 2.0 global alert systems are described. The approach for the follow-up of external alerts with a search for a neutrino excess in the archival data is defined. Finally, an overview of the current detector capabilities and a report after the first two years of operation are givenPostprint (published version

    Fiber Optic Monitoring of Active Faults at the Seafloor: the FOCUS project

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    Laser reflectometry (BOTDR), commonly used for structural health monitoring (bridges, dams, etc.), will for the first time be applied to study movements of an active fault on the seafloor 25 km offshore Catania Sicily. The goal of the European funded FOCUS project (ERC Advanced Grant) is to connect a 6-km long strain cable to the EMSO seafloor observatory in 2100 m water depth. Laser observations will be calibrated by seafloor geodetic instruments and seismological stations. A long-term goal is the development of dual-use telecom cables with industry partners