NESTOR

  Tzamarias S.  
Hellenic Open University

 

The NESTOR neutrino telescope is under construction and will be deployed at a depth of 4000m, 14km off the South West coast of Greece. This site provides excellent water transparency, shielding against the atmospheric muons, proximity to the shore, flat and wide sea bottom and stable geological and other environmental characteristics. 

A NESTOR detector unit consists of a hexagonal tower of 144 Optical Modules (OM) containing large photomultipliers (PMTs) of 15 diameter. The tower will be made of 12 hexagonal titanium floors, 32m in diameter, separated by 30m in vertical. 

The OMs are grouped in pairs, one pair in each corner of the hexagonal floors, with one OM pointing upwards and the other downwards. This pairing provides a 4π uniform detector response, enhances distinction between up-going and down-going particles and improves background rejection. 

At the center of each floor there is a 1m-diameter titanium sphere which houses the readout and digitizing electronics and slow controls of each floor. This electronic system is capable in real time: a) to capture and digitize the complete PMT waveforms and transmit to the shore station over 35km long optical fibers, b) to provide control of the experimental parameters from the shore laboratory c) to monitor the behavior of each PMT and the function of the trigger electronics and d) to operate with minimum dead time.

A 35km electrooptical cable (containing 18 fibers and an electrical conductor) is fully operational, transmitting environmental data from the experimental site to the shore laboratory whilst the deployment of NESTOR floors will start during the spring of 2002. 

In this report a description of the detector and the detector electronics, the current status of the detector installation and results of engineering runs will be presented.