LAERTIS, designed to collect environmental data from the deep-sea, is operated since 1999 and has been deployed several time at 4000m depth at the NESTOR site. Power and data were transferred through a 30-km electro-optical cable to the Shore Station. In this report, we describe briefly the LAERTIS instrumentation and present typical data that were collected successfully during those deployment demonstrating the importance of a deep-sea station permanently connected to shore.

NESTOR Collaboration has deployed one NESTOR module of the deep-sea neutrino telescope at a depth of 4000m, 14km off the southwest coast of Greece. The deployment site provides excellent environmental data. Power and data were transferred through a 30km electro-optical cable to the shore laboratory. In this report, we describe briefly the detector and the well-defined procedure for recovery and deployment of a detector attached to the electro-optical cable and we depict the deployment of several towers and complementary independent strings acoustically connected to the towers.

The key component of NESTOR, the deep-sea Cherenkov neutrino telescope, built in the Mediterranean, NW of Greece, is the optical module. The NESTOR Optical Module employs a PhotoMultiplier Tube (PMT) in a transparent glass pressure housing. The Hamamatsu PMT R8055-01, 13in. photomultiplier was selected for NESTOR to replace the old 15′′ Hamamatsu PMTs (R2018-03). Extensive tests have been made on the sensitivity, uniformity, time resolution and noise rates of 162 R8055-01 13in. PMTs

A module of the NESTOR underwater neutrino telescope, was deployed, in March 2003, at a depth of 3800m in order to test the overall detector performance and particularly that of the data acquisition systems. A prolonged period of running under stable operating conditions made it possible to measure the cosmic ray muon flux, I0cosa(θ).

NESTOR is a deep-sea neutrino telescope that is under construction in the Ionian Sea off the coast of Greece at a depth of about 4000m. This paper briefly reviews the detector structure and deployment techniques before describing in detail the calibration and engineering run of a test detector carried out in 2003. The detector was operated for more than 1 month and data was continuously transmitted to shore via an electro-optical cable laid on the sea floor. The performance of the detector is discussed and analysis of the data obtained shows that the measured cosmic ray muon flux is in good agreement with previous measurements and with phenomenological cosmic ray models.

NESTOR is a deep-sea neutrino telescope that is currently under construction in the Ionian Sea, off the coast of Pylos, Southwestern Greece, at a depth of approximately 4000 m. We outline briefly the layout of the telescope and summarize the present status of the project. The results of a one month continuous operation of a test unit using our standard detector modules is discussed. Data of the cosmic ray muon flux acquired with the help of an electro-optical cable during this period is presented. The data are in good agreement with earlier experiments at comparable, depth. In addition we discuss our results of bioluminescence measurements and other site and technical aspects.

Underwater neutrino detectors operate for large periods of time in a very hostile environment (i.e many km below sea level). Under these extreme conditions it is very important to know the operational and environmental conditions of the detector in order to take the corresponding actions when something goes wrong. In this note we describe the Online Monitor System of the NESTOR prototype, which was deployed in 2003 at a depth of 4000m in the Mediterranean Sea. The main purpose and the capabilities of the Online Monitor as well as its technical characteristics are presented in detail hereafter.

A module of the NESTOR underwater neutrino telescope was deployed at a depth of 3800 m in order to test the overall detector performance and particularly that of the data acquisition systems. A prolonged period of running under stable operating conditions made it possible to measure the cosmic ray muon flux, I-0 (.) cos(alpha)(theta), as a function of the zenith angle theta. Measured values of index alpha and the vertical intensity I-0(Graphics)are in good agreement with previous measurements and phenomenological predictions. (c) 2005 Elsevier B.V. All rights reserved.