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Deployment of the deep-sea neutrino telescope Baikal-GVD continues in Lake Baikal. By April 2022, ten telescope clusters, which include 2880 optical modules, were put into operation. One of the ...urgent tasks of the Baikal project is to study the possibility of increasing the detection efficiency of the detector based on the experience of its operation and the results obtained with other neutrino telescopes in recent years. In this paper, the authors consider a variant of optimizing the telescope configuration by installing an additional string of optical modules between the detector clusters (external string). An experimental version of the external garland was installed in Lake Baikal in April 2022. The paper presents the results from calculations of the efficiency of registration of neutrino events for a new setup configuration, the technical implementation of the system for recording and collecting data from the external garland, and the first results of its full-scale tests in Lake Baikal.
Abstract
The high-energy muon neutrino events of the IceCube telescope, that are triggered as neutrino alerts in one of two probability ranks of astrophysical origin, “gold” and “bronze”, have been ...followed up by the Baikal-GVD in a fast quasi-online mode since September 2020. Search for correlations between alerts and GVD events reconstructed in two modes, muon-track and cascades (electromagnetic or hadronic showers), for the time windows ±1 h and ±12 h does not indicate statistically significant excess of the measured events over the expected number of background events. Upper limits on the neutrino fluence will be presented for each alert.
Abstract
Baikal-GVD (Gigaton Volume Detector) is a neutrino telescope located in pure water of Lake Baikal. At the current stage (season 2021), detector is composed of 2304 optical modules arranged ...in 8 clusters. In searching for neutrino cascade events, light patterns produced via discrete stochastic energy losses along muon tracks create the most abundant background. Methods to separate cascade-like events from tracks and neutrino cascades in a single cluster have been developed and optimized. One of the method tries to find the maximum number of track hits amongst cascade hits, which are present in the muon bundle event. Other ones rely on the distributions of charges and positions of hits on optical modules associated with cascade events. All suppression methods were optimized by the Monte Carlo simulation datasets.
Abstract
The Baikal-GVD is a neutrino telescope situated in the deepest freshwater lake in the world — Lake Baikal. The design of the Baikal-GVD trigger system allows also to study the ambient light ...of the lake. The analysis of the optical light activity of Baikal water, particularly, time and spatial variations of the luminescence activity for data collected in years 2018, 2019, and 2020 is presented. For the first time we observed highly luminescent layer moving upwards with maximal speed of 28 m/day in January 2021.
The main goal of the Baikal-GVD deep-sea neutrino telescope is to detect high-energy neutrinos of astrophysical origin by reconstructing muon tracks or showers of particles generated in interactions ...of neutrino with water. Since 2020, Baikal-GVD has been monitoring IceCube telescope alerts about detecting neutrinos with energies of more than 100 TeV. This work presents results from searching for matches between Baikal-GVD events and IceCube neutrino alerts from September 2020 to April 2022.
Baikal-GVD is a 1 km
3
scale neutrino telescope now under construction in Lake Baikal. The sensitive volume of the detector is currently around 0.5 km
3
. Muons form through the exchange of W-bosons ...in the interaction between muon- and partial tau-neutrinos near the telescope. The muons then propagate to great distances in the lake’s water. Reconstructing their trajectory allows us to obtain the most accurate estimate of the direction of neutrinos at telescopes of this type. Angular resolution can be as good as 0.5° for fairly long muon tracks. The current state of affairs in analyzing track events at the Baikal-GVD is discussed.
The status of the Baikal-GVD neutrino telescope under construction and its main scientific results are presented. The detector consists of 2916 optical sensors located at 81 vertical strings deep ...below the surface of Lake Baikal. Its geometric configuration is optimized for detecting neutrinos with energies above 100 TeV. Events from muon neutrinos were identified, the flux of which is consistent with the expectation for the flux of atmospheric neutrinos. The data obtained during the alerts of the ANTARES and IceCube telescopes were analyzed. Candidate events for high-energy neutrinos of astrophysical origin have been obtained.
Abstract
The Large-scale deep underwater Cherenkov neutrino telescopes like Baikal-GVD, ANTARES or KM3NeT, require calibration and testing methods of their optical modules. These methods usually ...include laser-based systems which allow us to check the telescope responses to the light and for real-time monitoring of the optical parameters of water such as absorption and scattering lengths, which show seasonal changes in natural reservoirs of water. We will present a testing method of a laser calibration system and a set of dedicated tools developed for Baikal-GVD, which includes a specially designed and built, compact, portable, and reconfigurable scanning station. This station is adapted to perform fast quality tests of the underwater laser sets just before their deployment in the telescope structure, even on ice, without a darkroom. The testing procedure includes the energy stability test of the laser device, 3D scan of the light emission from the diffuser and attenuation test of the optical elements of the laser calibration system. The test bench consists primarily of an automatic mechanical scanner with a movable Si detector, beam splitter with a reference Si detector and, optionally, Q-switched diode-pumped solid-state laser used for laboratory scans of the diffusers. The presented test bench enables a 3D scan of the light emission from diffusers, which are designed to obtain the isotropic distribution of photons around the point of emission. The results of the measurement can be easily shown on a 3D plot immediately after the test and may be also implemented to a dedicated program simulating photons propagation in water, which allows us to check the quality of the diffuser in the scale of the Baikal-GVD telescope geometry.
Time synchronization system of Baikal-GVD Allakhverdyan, V.A.; Avrorin, A.D.; Avrorin, A.V. ...
Journal of instrumentation,
09/2021, Letnik:
16, Številka:
9
Journal Article
Recenzirano
The Baikal-GVD neutrino telescope currently consists of 8 clusters of 288 optical modules (photodetectors). One cluster comprises 8 strings, each of which is subdivided into 3 sections of 12 optical ...modules. This paper presents the methods of time synchronization between the different GVD components (optical modules, sections, clusters) and estimations of time synchronization accuracy.
Abstract
The first stage of the construction of the Baikal-GVD deep underwater neutrino telescope is planned to be completed in 2024. For the second stage of the detector deployment, a data ...acquisition system based on fiber-optic technologies has been proposed, which will allow for increased data throughput and more flexible trigger conditions. A dedicated test facility has been built and deployed at the Baikal-GVD site to test the new technological solutions. We present the principles of operation and results of tests of the new data acquisition system.
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