A. P. Koshechkin

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

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.

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 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 prototyping/early construction phase of the BAIKAL-GVD project

Abstract The prototyping phase of the BAIKAL-GVD project has been started in April 2011 with the deployment of a three string engineering array which comprises all basic elements and systems of the Gigaton Volume Detector (GVD) in Lake Baikal. In April 2012 the version of engineering array which comprises the first full-scale string of the GVD demonstration cluster had been deployed and operated during 2012. The first stage of the GVD-cluster which consists of three strings was deployed in April 2013. We review the prototyping phase of the BAIKAL-GVD project and describe the configuration and design of the 2013 engineering array.

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.

Search for Neutrinos from Gamma-Ray Bursts with the Baikal Neutrino Telescope NT200

We present the results of our search for neutrino events coinciding in time and direction with gamma-ray bursts (GRBs) with the Baikal underwater neutrino telescope NT200. No events confirming a neutrino accompaniment of GRBs have been detected. Model-independent limits (Greens function) on the neutrino flux from GRBs have been obtained. For the Waxman-Bahcall neutrino spectrum, the limit on the neutrino flux from a GRB has been found to be Eν2Φν ⩽ 1.1 × 10−6 GeV cm−2 s−1 sr−1.

Sensitivity of the Baikal-GVD neutrino telescope to neutrino emission toward the center of the galactic dark matter halo

We analyze sensitivity of the gigaton volume telescope Baikal-GVD for detection of neutrino signal from dark matter annihilations or decays in the Galactic Center. Expected bounds on dark matter annihilation cross section and its lifetime are found for several annihilation/decay channels.