Winter Expedition 2023 to Construct the Baikal-GVD Deep Underwater Neutrino Telescope Completed

During the 2023 Winter Expedition, the Baikal-GVD Collaboration installed two new telescope clusters, repaired and updated previously mounted detector elements and proceeded with developing the data transmission system inside the facility via optical cables.

     The Baikal-GVD Neutrino Telescope is aimed at detecting and investigating ultrahigh-energy neutrino fluxes from astrophysical sources. Scientists are going to study not only processes with huge energy emission from the distant past but also galaxy evolution, supermassive black hole formation and particle acceleration mechanisms.

     The Baikal Neutrino Telescope is a neutrino detector located in Lake Baikal 3.6 km offshore at a depth of about 1300 m. This unique scientific facility is an important tool of multimessenger astronomy, a new powerful method for investigating the Universe. Baikal-GVD is one of the three operating neutrino telescopes across the globe and is a constituent of the Global Neutrino Network (GNN), along with IceCube at the South Pole and KM3NeT in the Mediterranean Sea.

     The Baikal-GVD Telescope is the largest in the Northern Hemisphere and the second by size in the world. To date, 12 clusters, spaced 250 to 300 m from each other, are put into operation. Since 8 April 2023, they have been taking data. Each cluster is an individual detector of 8 vertical strings with optical modules along them (36 items on each string). At present, the telescope comprises about 3500 photodetectors. By 2027, the facility volume is scheduled to be about one cubic kilometre.

      “The 2023 season turned out to be a strength test to the expedition team. The weather made the challenge even tougher, but at the same time, it provided us with the thick and safe ice sheet until the activities on the ice were finished. Despite these conditions, the systematic changes both in preparing the equipment and in deploying the facility were made. I would like to mention the increased expertise of the team—a forced restructuring did not impede the fulfilment of previously scheduled tasks,” remarks Igor Anatolevich Belolaptikov, the head of expedition activities, head of the facility of the Dzhelepov Laboratory of Nuclear Problems of the Joint Institute for Nuclear Research.

     “A planned step on ramping up the effective volume of the detector was successfully made. To implement the initial project on constructing the high-energy neutrino detector with an effective volume of about one cubic kilometre, two or three steps are left. The outlines of further development of the detector on the basis of the fibre-optical data-acquisition system start showing up,” says Grigory Vladimirovich Domogatsky, the Baikal-GVD Collaboration head, corresponding member of RAS, the head of the Laboratory of High-Energy Neutrino Astrophysics of the Institute for Nuclear Research of RAS.

     The Baikal-GVD Neutrino Telescope is being constructed by concerted efforts of the international collaboration with the leading role of the Institute for Nuclear Research of the Russian Academy of Sciences (INR of RAS, Moscow), the founder of this experiment and the direction “high-energy neutrino astronomy” in the world, and of the Joint Institute for Nuclear Research (JINR, Dubna). Above 70 scientists and engineers from nine research centres of Russia, the Czech Republic, Slovakia and Kazakhstan participate in the project.

     The 2023 expedition was organized by the Institute for Nuclear Research of RAS (Moscow) and the Joint Institute for Nuclear Research (Dubna).