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.
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.
It 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.
DANSS is a highly segmented 1 m3 plastic scintillator detector. Its 2500 one meter long scintillator strips have a Gd-loaded reflective cover. The DANSS detector is placed under an industrial 3.1 ...GWth reactor of the Kalinin Nuclear Power Plant 350 km NW from Moscow. The distance to the core is varied on-line from 10.7 m to 12.7 m. The reactor building provides about 50 m water-equivalent shielding against the cosmic background. DANSS detects almost 5000 ν˜e per day at the closest position with the cosmic background less than 3%. The inverse beta decay process is used to detect ν˜e. Sterile neutrinos are searched for assuming the 4ν model (3 active and 1 sterile ν). The exclusion area in the Δm142,sin22θ14 plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore results do not depend on the shape and normalization of the reactor ν˜e spectrum, as well as on the detector efficiency. Results are based on 966 thousand antineutrino events collected at three different distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters up to sin22θ14<0.01 in the most sensitive region.
•Simulations of δM(H) plots of nanocrystalline hard magnetic alloys were performed.•Intergrain exchange interaction constant was estimated from δM(H) of Nd-FeCo-B alloy.•Effect of grain size ...dispersion on δM(H) of nanocrystalline alloys was considered.
Magnetic properties of nanocrystalline hard magnetic alloys such as coercivity and maximum energy product are strongly depended on microstructure and interactions between grains. There are a lot of advanced experimental techniques for microstructure characterization but the analysis of intergrain interactions is still challenging. One of the wide-spread methods for doing that is plotting δM(H). This work is aimed to elucidate how different factors effect δM(H) plots for high-anisotropy nanocrystalline alloys. Specifically, changes of δM(H) plots caused by both intergrain exchange and magnetostatic interactions, grain size dispersion, and demagnetization factor are analyzed systematically using macrospin-based simulations. It is demonstrated that all these factors should be considered for a reliable evaluation of exchange coupling in alloys. A concept of such analysis is presented and applied to rapidly quenched Nd-FeCo-B alloy.
This study examines the accessory wodginite and the discovery of titanium-bearing wodginite and Fe and Ti-bearing wodginite in lithium-fluorine granites from the Abu Dabbab and Nuweibi massifs in ...Eastern Egypt. The wodginite group’s mineral association includes tantalum-bearing cassiterite and tin-bearing tantalum–niobate minerals: tantalite-(Mn), columbite-(Mn), and microlite. Three forms of wodginite crystallization were identified: (1) rims around columbite-(Mn) and tantalite-(Mn) varying from 1.5 to 21.9 μm in thickness, (2) micro-inclusions in cassiterite ranging from 5.4 to 27.0 μm in size, and (3) autonomous crystals measuring 3–124 μm in length. Wodginite in the Nuweibi massif is mainly found in porphyritic granite of late-stage porphyry intrusion. It has a similar composition to the worldwide wodginite of rare-metal granites, but exhibits a lower content of TiO2 (average 0.54%) and is a mineral indicator of rich tantalum ore deposits. In contrast, wodginite in the Abu Dabbab massif is replaced by titanium-bearing wodginite (Ti/(Sn + BTa + Ti + Fe3+) = 0.23) and is associated with Fe and Ti-bearing wodginite. Wodginite and Ti-bearing wodginite are maximally enriched in manganese (Mn/(Mn + Fe2+ +Ca) = 0.95), expressed in all intrusive phases of the massif, and are mineral indicators of tantalum-bearing granites with associated cassiterite-quartz mineralization.
This paper contains a review of beetle species (Coleoptera) described from Baltic amber. The compiled checklist contains 434 species from 149 extinct and 138 extant genera. At this moment, 90 ...families are registered. The best known and therefore most diverse families are: Staphylinidae (77 described spp.), Curculionidae (46 spp.), Carabidae (32 spp.), Scirtidae (21 spp.), Cleridae (17 spp.), Elateridae (16 spp.), Dermestidae (16 spp.) and Cerambycidae (15 spp.). Possibly, about 530 species of beetles can be additionally described from Baltic amber.
PDF
