Sedimentation and Fouling of Optical Surfaces at the ANTARES Site

ANTARES is a project leading towards the construction and deployment of a neutrino telescope in the deep Mediterranean Sea. The telescope will use an array of photomultiplier tubes to detect the Cherenkov light emitted by muons resulting from the interaction with matter of high energy neutrinos. In the vicinity of the deployment site the ANTARES collaboration has performed a series of in-situ measurements to study the change in light transmission through glass surfaces during immersions of several months. The average loss of light transmission is estimated to be only ~2% at the equator of a glass sphere one year after deployment. It decreases with increasing zenith angle, and tends to saturate with time. The transmission loss, therefore, is expected to remain small for the several year lifetime of the ANTARES detector whose optical modules are oriented downwards. The measurements were complemented by the analysis of the ^{210}Pb activity profile in sediment cores and the study of biofouling on glass plates. Despite a significant sedimentation rate at the site, in the 0.02 - 0.05 cm.yr^{-1} range, the sediments adhere loosely to the glass surfaces and can be washed off by water currents. Further, fouling by deposits of light-absorbing particulates is only significant for surfaces facing upwards.Comment: 18 pages, 14 figures (pdf), submitted to Astroparticle Physic

The ANTARES Optical Module

The ANTARES collaboration is building a deep sea neutrino telescope in the Mediterranean Sea. This detector will cover a sensitive area of typically 0.1 km-squared and will be equipped with about 1000 optical modules. Each of these optical modules consists of a large area photomultiplier and its associated electronics housed in a pressure resistant glass sphere. The design of the ANTARES optical module, which is a key element of the detector, has been finalized following extensive R & D studies and is reviewed here in detail.Comment: 26 pages, 15 figures, to be published in NI

ANTARES proposal: Towards a large scale high energy cosmic neutrino undersea detector

The ANTARES collaboration propose to observe high energy cosmic neutrinos using a deep sea Cherenkov detector. The sky survey with high energy neutrinos is complementary to the observations with photons and will shed a new light on the understanding of the origin of cosmics rays. We propose to explore the possibility of a km-scale detector to be installed in a deep site in the Mediterranean sea, for which a broad collaboration will be needed. With the help of collaborators and partners which have experience in sea science engineering (COM, CSTN, CTME, IFREMER, France Télécom Câbles, INSU-CNRS...) we will test the sea engineering part of a detector including test deployments close to the Toulon coast (France) where technical support is available and where several sites at depths down to 2500~m are easily accessible. We propose to build and install a demonstrator (a fully equipped 3-dimensional test array) the design of which can be extended to a km-scale detector. During the same time, autonomous systems allowing to measure undersea optical parameters in view of the selection of a site for the future km-scale detector will be realized