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The DANSS experiment at Kalininskaya NPP is running for already 8 years since April 2016. The largest in the world in the single experiment statistics of 8.5 million inverse beta-decay events is already collected. The data sample covers 4 full cycles of the industrial power reactor. DANSS experimental program includes both a search for physics beyond the Standard Model, like sterile neutrinos or large extra dimensions, and applied studies connected to reactor monitoring using electron antineutrino flux. The model independent exclusion area in the sterile neutrino parameter space for hypothesis extends till for eV , where sensitivity of the experiment is the best. Our data show presence of antineutrinos with energies above 10 MeV in the reactor spectrum with significance of 6.8 . Along with ongoing statistics collection DANSS is preparing for an upgrade, which shall significantly improve its energy resolution and also increase the fiducial volume. The article covers recent analysis results and the upgrade status.

Ageing of the plastic scintillators plays a significant role in the degradation of detectors’ performance. Several effects are considered responsible for this process such as mechanical stresses, water penetration and oxidation due to exposure to ultraviolet radiation. The DANSS detector core consists of 2500 polystyrene based scintillation plates with wavelength shifting fiber readout (strips). The detector is located just below an industrial nuclear reactor of Kalininskaya NPP. The room housing the detector is air conditioned and has very low humidity. The temperature of about 20 C was maintained at the detector core. The performance of the strips is permanently monitored with atmospheric muons passing through the detector. Six years of measurements since April 2016 till March 2022 are reported. We observe the average light yield degradation of the strips at the level /year. The decrease of the wavelength shifting fiber attenuation length is /year.

Experiments with reactor antineutrino provide a wide range of physics opportunities. Solid state scintillator detector DANSS is placed just below the core of 3.1 GWth industrial reactor of Kalininskaya Nuclear Power Plant. The detector features the world highest counting rate of 5000 neutrino events per day with the cosmic rays induced background as low as 130 events per day. The talk covers detector performance of a year and a half operation, reactor power measurements via neutrino flux and effects of fuel burning over the reactor campaign.

The DANSS experiment is a scintillation spectrometer of reactor antineutrinos placed at the Unit 4 reactor of the Kalinin Nuclear Power Plant about 300 km northwest of Moscow. The main fundamental aim of the experiment is search for sterile neutrinos. The experiment was commissioned in April 2016 and regular data taking has been carried out since October 2016. 7.7 million of inverse beta-decay events have been collected by March 2023. A vast exclusion area of the sterile neutrino parameters was set. In the region of the best sensitivity the limit reached . The reactor power has been monitored for 6.5 years. The dispersion that is not related to single measurement statistics is below 0.5%, which gives an upper estimate of the precision of the standard NPP power measurements at the level of at least 0.5%. New scintillator detectors designed to upgrade the DANSS facility were tested at an accelerator beam. Light yield better than 140 ph.e./MeV was obtained. This paper describes the results obtained during the last year and the facility upgrade plans.

AbstractIt is proposed to use the mathematical apparatus of wavelet transforms combined with the clustering of the obtained and transformed coefficients to detect attacks in the traffic of backbone networks. The wavelet transform coefficients obtained from the parameters of network packets are checked for the degree of multiple dependence, on the basis of which the standard deviation is calculated and the resulting coefficients are clustered to identify anomalies of the investigated network flow. The efficiency of the proposed method is confirmed by the results of experiments on detecting denial of service attacks.

Li-F granites from the Kester deposit (Yana Plateau in Yakutia, Russia) are proved to be connected with a rare-metal complex of accessory minerals: montebrasite, columbite-(Mn), columbite-(Fe), tantalite-(Mn), Ta-bearing cassiterite, U-bearing microlite, W-bearing ixiolite, niobian ferberite, U–Hf-rich zircon, and Ta-bearing rutile. Accessory wodginite was discovered at depths of up to 150 m in association with tantalite-(Mn), columbite-(Mn), and cassiterite. According to the content of WO3 (1.23%–3.33%) and the values of Mn/(Mn + Fet) and Ta/(Ta + Nb), Yakut wodginite is an intermediate mineral between wodginite and a hypothetical mineral of the wodginite group—”wolframowodginite”. The discovery of tungsten-bearing wodginite at the Kester deposit confirms the widespread presence of tungstic and tungsten-bearing accessory minerals in Li-F granites in the Russian Far East. It also serves as an indicator of rare-metal tin-tantalum-bearing granites and pegmatites.

AbstractThe mercury (Hg) accumulation and migration in Arctic ecosystems is most relevant in the context of ever-increasing anthropogenic impact and climate change, potentially enhancing the transformation of Hg compounds and their involvement in biogeochemical cycles. We report the results of a comprehensive study of the background Hg content, its vertical distribution, and the factors determining Hg accumulation in different types of tundra soils in the northeastern European Russia. The Hg content is determined using atomic absorption spectrometry with pyrolysis of samples and GIS technologies as a tool for analysis of the spatial distribution of Hg. As is shown, spatial heterogeneity of the Hg distribution in tundra soils is determined by a complex effect of the soil physicochemical properties. The peat and gley horizons enriched with organic matter and physical clay fraction are the most efficient Hg accumulators, whereas in podzols active vertical migration of Hg takes place under conditions of a percolative soil water regime. We suggest that the threshold limit values of Hg should be based on a 95% confidence interval to standardize the regional background Hg concentrations. This allows us to take into account natural background fluctuations and to exclude extreme. The maximum threshold limit values of Hg content are observed in bod-podzolic (230–260 μg/kg), surface-gley tundra (240 μg/kg), and peaty-gley tundra (230 μg/kg) soils. These results are important for evaluating the background Hg levels, developing environmental protection measures, and predicting changes in the Hg behavior in the context of permafrost degradation and alterations in hydrothermal regime.

Analytical data on fauna of the beetles and flora of vascular plants from Baltic amber are given. The community of the amber forest is reconstructed on the basis of these data. It was a thermophilic, humidmixed forest similar to modern subtropical forests of Eastern and Southeastern Asia. The existing reconstructions representing this community as a mountain forest predominated by conifers are not confirmed.

The DANSS detector (Alekseev et al. in JINST 11:P11011, 2016) is located directly below a commercial reactor core at the Kalinin Nuclear Power Plant. Such a position provides an overburden about 50 m.w.e. in vertical direction. In terms of the cosmic rays it occupies an intermediate position between surface and underground detectors. The sensitive volume of the detector is a cubic meter of plastic scintillator with fine segmentation and combined PMT and SiPM readout, surrounded by multilayer passive and active shielding. The detector can reconstruct muon tracks passing through its sensitive volume. The main physics goal of the DANSS experiment implies the antineutrino spectra measurements at various distances from the source. This is achieved by means of a lifting platform so that the data is taken in three positions – 10.9, 11.9 and 12.9 meters from the reactor core. The muon data were collected for nearly four calendar years. The overburden parameters ⟨Ethrcosθ⟩ and ⟨Ethr⟩, as well as the temperature and barometric correlation coefficients are evaluated separately for the three detector positions and, in each position, in three ranges of the zenith angle – for nearly vertical muons with cosθ>0.9, for nearly horizontal muons with cosθ<0.36, and for the whole upper hemisphere.

Acritus sutirca sp. nov. is described and illustrated from Eocene Baltic amber on the basis of one adult male specimen. As the first extinct member of the subfamily Abraeinae (Histeridae) and the smallest known fossil histerid specimen, this material was examined using a combination of light microscopy and X-ray micro-computed tomography (µCT). Internal features of the abdomen are well preserved, allowing us to study sclerotized parts of the aedeagus and illustrate these structures in detail. The current finding expands the range of known Histeridae diversity from the Eocene (48–34 Ma) “amber forests” of Europe. The absolute size limits and the probable average size for Baltic amber coleopteran inclusions are also briefly discussed (urn:lsid:zoobank.org:pub:A2B17479-8628-47C7-A8D4-3E0789BF088B).