The AMANDA Neutrino Telescope: Principle of Operation and First Results

AMANDA is a high-energy neutrino telescope presently under construction at the geographical South Pole. In the Antarctic summer 1995/96, an array of 80 optical modules (OMs) arranged on 4 strings (AMANDA-B4) was deployed at depths between 1.5 and 2 km. In this paper we describe the design and performance of the AMANDA-B4 prototype, based on data collected between February and November 1996. Monte Carlo simulations of the detector response to down-going atmospheric muon tracks show that the global behavior of the detector is understood. We describe the data analysis method and present first results on atmospheric muon reconstruction and separation of neutrino candidates. The AMANDA array was upgraded with 216 OMs on 6 new strings in 1996/97 (AMANDA-B10), and 122 additional OMs on 3 strings in 1997/98.Comment: 36 pages, 23 figures, submitted to Astroparticle Physic

The BAIKAL Neutrino Telescope: From NT200 to NT200+.

We review the status of the Baikal Neutrino Telescope, which has recently been upgraded to the 5 Mton detector NT200+. We present results on searches for upward going atmospheric neutrinos and relativistic magnetic monopoles, obtained from 1998-2002 with the predecessor detector NT200. A search for very high energy neutrinos yields an upper limit on the extraterrestrial diffuse neutrino flux for 20 TeV < E < 50 PeV. We describe the strategy of upgrading NT200 to NT200+ and creating a detector on the Gigaton (km3) scale at lake Baikal. R&D activities on that next stage detector have been started