Asp-15—A stationary device for the measurement of the optical water properties at the NT200 neutrino telescope site

Abstract

a b s t r a c tThe operation of large underwater neutrino telescopes requires the precise knowledge of the water parameters governing light absorption and scattering, as well as a continuous monitoring of these parameters. For this purpose, a stationary underwater device, ASP-15, has been developed by the Baikal collaboration. We describe the basic assumptions and formulae behind ASP-15, the methods how absorption length, scattering length and phase functions are determined, the design of the device, and give some results obtained over many years of operation in conjuction with the Baikal telescope NT200.

Neutrino Telescope in Lake Baikal: Present and Nearest Future

“…According to a study made with a specialized device, the light absorption length in the deep lake water reaches maximal values, ~ 24 m, at a wavelength of 488 nm [11]. The effective light scattering length is ~ 480 m (at 475 nm; see [11] for details). Both the absorption and scattering characteristics show variations with depth and over time.…”

Status and recent results of the BAIKAL-GVD project

“…The BAIKAL-GVD project is a logical extension of the research and development work performed over the last several years by the BAIKAL Collaboration. The optical properties of the lake deep water have been established [1], and the detection of high-energy neutrinos has been demonstrated with the detector NT200 [2,3]. This achievement represents a proof of concept for commissioning the new instrument, Gigaton Volume Detector (BAIKAL-GVD), with superior detector performance and an effective telescope size at or above the kilometerscale.…”

Monitoring of optical properties of deep lake water

“…The methodological basis for measuring the absorption and scattering by such a device is discussed in detail in [2,3,4]. The algorithm used in this study for measuring the dependencies of absorption and scattering of light is as follows.…”