Transmission of light in deep sea water at the site of the Antares neutrino telescope

Abstract

The ANTARES neutrino telescope is a large photomultiplier array designed to detect neutrino-induced upward-going muons by their Cherenkov radiation. Understanding the absorption and scattering of light in the deep Mediterranean is fundamental to optimising the design and performance of the detector. This paper presents measurements of blue and UV light transmission at the ANTARES site taken between 1997 and 2000. The derived values for the scattering length and the angular distribution of particulate scattering were found to be highly correlated, and results are therefore presented in terms of an absorption length λ abs and an effective scattering length λ eff sct . The values for blue (UV) light are found to be λ abs ≃ 60(26) m, λ eff sct ≃ 265(122) m, with significant (∼15%) time variability. Finally, the results of ANTARES simulations showing the effect of these water properties on the anticipated performance of the detector are presented.

Search for relativistic magnetic monopoles with five years of the ANTARES detector data

“…As shown in table 1, the contribution of atmospheric neutrinos is almost negligible with respect to atmospheric muons and the effects of these uncertainties have been ignored. Concerning atmospheric muons, the dominant detector effects are connected to the angular acceptance of the optical module [40] and to the absorption and scattering lengths in water [41]. The maximum ±15% uncertainty on the optical module acceptance and the ±10% on the light absorption length in water over the whole wavelength spectrum yields an overall +35% −30% effect on the expected muon rate [37].…”

Measurement of the atmospheric muon flux with a 4GeV threshold in the ANTARES neutrino telescope

“…From the Monte Carlo simulation based on MUPAGE, the value for a pair of nominal storeys is A = 87 light absorption length in the sea water [3,14]. A low energy cutoff of 1 GeV has been used for the flux integration.…”

Measurement of the group velocity of light in sea water at the ANTARES site

“…In the second row, the variation in percentage of the fitted value is shown when the absorption length changes by ±50%. Finally, in the third row the variation in percentage of the fitted value is shown when the scattering length is varied between 20 m and 70 m [11]. As can be seen, the latter is the largest contribution to the systematic uncertainty.…”