The optical module of the Baikal deep underwater neutrino telescope

A deep underwater Cherenkov telescope has been operating since 1993 in stages of growing size at 1.1 km depth in Lake Baikal. The key component of the telescope is the Optical Module (OM) which houses the highly sensitive phototube QUASAR-370. We describe design and parameters of the QUASAR-370, the layout of the optical module, the front-end electronics and the calibration procedures, and present selected results from the five-year operation underwater. Also, future developments with respect to a telescope consisting from several thousand OMs are discussed.Comment: 30 pages, 24 figure

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

Methodische Untersuchungen und Entwicklung eines Kalibrationssystems fuer das Neutrinoteleskop NT-200 im Baikalsee

The thesis describes the construction, function and theoretical basis of the Lake Baikal detector, one of the four DUMAND projects (deep underwater muon and neutrino detectors). Results gained during the survey of photomultiplier tubes (pmt) for the underwater experiments are presented with special regard to the hybride pmt quasar 370 used in the Baikal experiment. Part of the underwater know how has been derived from design and operation of the Zeuthen ministring consisting of six optical molecules and is documented in this work. A laser system for time calibration of the NT-200 detector, its operation in 1993/94, the calibration procedure and its results are presented, and the influence of the calibration on the reconstruction precision is discussed. (WEN)Available from TIB Hannover: RR 4482(95-03) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Analog optical transmission of fast photomultiplier pulses over distances of 2 km

New LED-transmitters have been used to develop a new method of fast analog transmission of PMT pulses over large distances. The transmitters, consisting basically of InGaAsP LEDs with the maximum emission of light at 1300 nm, allow the transmission of fast photomultiplier pulses over distances of more than 2 km. The shape of the photomultiplier pulses is maintained, with an attenuation less than 1 dB/km. Typical applications of analog optical signal transmission are surface air shower detectors and underwater/ice neutrino experiments, which measure fast Cherenkov or scintillator pulses at large detector distances to the central DAQ system. (orig.)Available from TIB Hannover: RA 2999(96-186) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman