6 research outputs found
Long-term measurement of acoustic background in very deep sea
The NEMO (NEutrino Mediterranean Observatory) Collaboration installed, 25 km E offshore the port of Catania (Sicily) at 2000 m depth, an underwater laboratory to perform long-term tests of prototypes and new technologies for an underwater high energy neutrino km3-scale detector in the Mediterranean Sea. In this framework the Collaboration deployed and successfully operated for about two years, starting from January 2005, an experimental apparatus for on-line monitoring of deep-sea noise. The station was equipped with four hydrophones and it is operational in the range 30 Hz–43 kHz. This interval of frequencies matches the range suitable for the proposed acoustic detection technique of high energy neutrinos. Hydrophone signals were digitized underwater at 96 kHz sampling frequency and 24 bits resolution. The stored data library, consisting of more than 2000 h of recordings, is a unique tool to model underwater acoustic noise at large depth, to characterize its variations as a function of environmental parameters, biological sources and human activities (ship traffic, etc.), and to determine the presence of cetaceans in the area
NEMO: Status of the Project
The activities towards the realisation of a km3 Cherenkov neutrino detector, carried out by the NEMO Collaboration
are described. Long term exploration of a 3500 m deep site close to the Sicilian coast has shown that it is
optimal for the installation of the detector. A complete feasibility study, that has considered all the components
of the detector as well as its deployment, has been carried out demonstrating that technological solutions exist
for the realization of an underwater km3 detector. The realization of a technological demonstrator (the NEMO
Phase 1 project) is under way
Status of the NEMO project
Activities leading to the realization of a km3 Cherenkov neutrino detector, carried out by the NEMO collaboration,
are described. Long term exploration of a 3500 m deep site in the Mediterranean close to the Sicilian coast
has shown that it is optimal for the installation of the detector. A complete feasibility study, which has considered
all the components of the detector, as well as its deployment, has been carried out demonstrating that technological
solutions exist for the realization of the km3 detector. The realization of a technological demonstrator (the
NEMO Phase 1 project) is under way
Procedures and results of the measurements on large area photomultipliers for the NEMO project
The selection of the photomultiplier plays a crucial role in the R&D activity related to a large-scale underwater neutrino telescope. This paper illustrates the main procedures and facilities used to characterize the performances of 72 large area photomultipliers, Hamamatsu model R7081 sel. The voltage to achieve a gain of 5Ă—17, dark count rate and single photoelectron time and charge properties of the overall response were measured with a properly attenuated 410 nm pulsed laser. A dedicated study of the spurious pulses was also performed. The results prove that the photomultipliers comply with the general requirements imposed by the project
NEMO: Status of the Project
The activities towards the realisation of a km3 Cherenkov neutrino detector, carried out by the NEMO Collaboration
are described. Long term exploration of a 3500 m deep site close to the Sicilian coast has shown that it is
optimal for the installation of the detector. A complete feasibility study, that has considered all the components
of the detector as well as its deployment, has been carried out demonstrating that technological solutions exist
for the realization of an underwater km3 detector. The realization of a technological demonstrator (the NEMO
Phase 1 project) is under way
Timing calibration for the NEMO (NEutrino Mediterranean Observatory) prototype2007 IEEE Nuclear Science Symposium Conference Record
The timing calibration is a delicate operation to perform for assuring the full functionality of a large underwater neutrino telescope. In this paper we illustrate the main features of our system for timing calibration tailored to the needs of the prototype of the NEMO (NEutrino Mediterranean Observatory) apparatus. We point out that the approach proposed can be easily adapted to work in any underwater neutrino telescope