G. V. Domogatsky

The Baikal underwater neutrino telescope: Design, performance and first results

Abstract A first deep underwater detector for muons and neutrinos, NT-200 , is currently under construction in Lake Baikal. Part of the detector, NT-36 , with 36 photomultiplier tubes at three strings, has been installed in 1993. This array allowed for the first time a three-dimensional mapping of Cherenkov light deep underwater. Since then, various arrays have been almost continuously taking data. Presently a 96-PMT array is operating. We describe the NT-200 detector design and present results obtained with NT-36 .

The optical module of the Baikal deep underwater neutrino telescope

Abstract A deep underwater Cherenkov telescope has been operating since 1993 in stages of growing size at 1.1xa0km 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.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.

Search for a diffuse flux of high-energy extraterrestrial neutrinos with the NT200 neutrino telescope

Abstract We present the results of a search for high-energy extraterrestrial neutrinos with the Baikal underwater Cherenkov detector NT200, based on data taken in 1998–2003. Upper limits on the diffuse fluxes of νexa0+xa0νμxa0+xa0ντ, predicted by several models of AGN-like neutrino sources, are derived. For an E−2 behavior of the neutrino spectrum, our limit is E2Φν(E)xa0 ν ¯ e diffuse flux is Φ ν ¯ e 3.3 × 10 - 20 cm - 2 s - 1 sr - 1 GeV - 1 .

Registration of atmospheric neutrinos with the BAIKAL Neutrino Telescope NT-96

We present first neutrino induced events observed with a deep underwater neutrino telescope. Data from 70 days effective life time of the BAIKAL prototype telescope NT-96 have been analyzed with two different methods. With the standard track reconstruction method, 9 clear upward muon candidates have been identified, in good agreement with 8.7 events expected from Monte Carlo calculations for atmospheric neutrinos. The second analysis is tailored to muons coming from close to the opposite zenith. It yields 4 events, compared to 3.5 from Monte Carlo expectations. From this we derive a 90 % upper flux limit of 1.1 * 10^-13 cm^-2 sec^-1 for muons in excess of those expected from atmospheric neutrinos with zenith angle > 150 degrees and energy > 10GeV.We present neutrino induced events observed with a deep underwater neutrino telescope. Data from 70 days effective life time of the BAIKAL prototype telescope NT-96 have been analyzed with two different methods. With the standard track reconstruction method, 9 clear upward muon candidates have been identified, in good agreement with expectation from Monte Carlo calculations for atmospheric neutrinos. The second analysis is tailored to muons coming from close to the opposite zenith. It yields 4 events, compared to 3.5 from Monte Carlo expectations. From this we derive a 90% upper flux limit of 1:1 10 13 cm 2 sec 1 for muons in excess of those expected from atmospheric neutrinos with zenith angle > 150 degrees and energy > 10 GeV.Abstract We present the first neutrino induced events observed with a deep underwater neutrino telescope. Data from 70 days effective life time of the BAIKAL prototype telescope NT-96 have been analyzed with two different methods. With the standard track reconstruction method, 9 clear upward muon candidates have been identified, in good agreement with 8.7 events expected from Monte Carlo calculations for atmospheric neutrinos. The second analysis is tailored to muons coming from close to the opposite zenith. It yields 4 events, compared to 3.5 from Monte Carlo expectations. From this we derive a 90% upper flux limit of 1.1 · 10−13 cm−2 sec−1 for muons in excess of those expected from atmospheric neutrinos with zenith angle > 150 degrees and energy > 10 GeV.

Search for high-energy neutrinos in the Baikal neutrino experiment

A new analysis of the data from the NT200 neutrino telescope based on the reconstruction of parameters for high-energy showers generated in neutrino interactions has yielded new upper limits on the diffuse neutrino fluxes predicted by a number of theoreticalmodels. The upper limit on the all-flavor neutrino flux with an energy spectrum E−2 is E2Φν < 2.9 × 10−7 GeV cm−2 s−1 sr−1.

An upper limit on the diffuse flux of high energy neutrinos obtained with the Baikal detector NT-96

Abstract We present the results of a search for high-energy neutrinos with the Baikal underwater Cherenkov detector NT-96. An upper limit on the diffuse flux of ν e + ν μ + ν μ of E 2 Φ ν (E) −5 cm −2 s −1 sr −1 GeV within neutrino energy range 10 4 –10 7 GeV is obtained, assuming an E −2 behavior of the neutrino spectrum.

The prototype string for the km3-scale Baikal neutrino telescope

Abstract A prototype string for the future km 3 -scale Baikal neutrino telescope has been deployed in April, 2008, and is fully integrated into the NT200+ telescope. All basic string elements–optical modules (with 12″/13″ hemispherical photomultipliers), 200xa0MHz FADC readout and calibration system–have been redesigned following experience with NT200+. First results of in-situ operation of this prototype string are presented.

The BAIKAL neutrino experiment—Physics results and perspectives

We review the status of the Lake Baikal Neutrino Experiment. The Neutrino Telescope NT200 has been operating since 1998 and has been upgraded to the 10 Mton detector NT200+ in 2005. We present selected astroparticle physics results from long-term operation of NT200. Also discussed are activities towards acoustic detection of UHE-energy neutrinos, and results of associated science activities. Preparation towards a km3-scale (Gigaton volume) detector in Lake Baikal is currently a central activity. As an important milestone, a km3-prototype string, based on completely new technology, has been installed and is operating together with NT200+ since April, 2008.

The BAIKAL neutrino experiment: From NT200 to NT200+

Abstract The Baikal Neutrino Telescope has been operating in its NT200 configuration since April, 1998. The telescope has been upgraded in April, 2005 to the 10xa0Mton scale detector NT200+. Its main physics goal is the detection of signals from high energy neutrino cascades. NT200+ reaches a 3-year sensitivity of 2 × 10 - 7 cm - 2 s - 1 sr - 1 GeV for an all-flavor diffuse cosmic E - 2 neutrino flux for energies 10 2 TeV – 10 5 TeV . Design and sensitivity of NT200+ are described. NT200+ is forming the basic building block of a future km3-scale (gigaton-volume) Baikal Telescope. Research and development work on that next stage detector has started.

The BAIKAL neutrino project: status report

We review the present status of the Baikal Neutrino Project and present preliminary results of a search for upward going atmospheric neutrinos, WIMPs and magnetic monopoles obtained with the detector NT-2000 during 1998. Also the results of a search for very high energy neutrinos with partially completed detector in 1996 are presented.We review the present status of the Baikal Neutrino Project and present preliminary results of a search for upward going atmospheric neutrinos, WIMPs and magnetic monopoles obtained with the detector NT-2000 during 1998. Also the results of a search for very high energy neutrinos with partially completed detector in 1996 are presented.