arXiv subjects

S. Kazartsev

Publications and source records attributed to S. Kazartsev.

13 recordsLinked to original sources

arXiv2026

First observation of single beta decay of $^{96}$Zr

The single beta decay of $^{96}$Zr has been detected for the first time using a 211 cm$^3$ low-background HPGe detector and an external source consisting of two samples of enriched zirconium (atomic fraction of $^{96}$Zr is 88.28%, total mass is 140.65 g). During the search for the $β$ decay of $^{96}$Zr, the $β$ decay of the daughter nucleus $^{96}$Nb to the excited states of $^{96}$Mo has been observed. The $γ$-ray cascade produced by the $^{96}$Mo nucleus while de-exciting to the ground state has been detected with the HPGe detector. The experiment has been carried out at the Baksan Neutrino Observatory. It has produced 12625.34 h of data. The half-life of the single beta decay of $^{96}$Zr is measured to be $T_{1/2} = [2.27^{+0.53}_{-0.36}(stat) \pm 0.27(syst)]\times10^{20}$ yr.

nucl-ex↗

arXiv2026

Determination of the Muon Lifetime in $^{76}$Se with the MONUMENT experiment

Ordinary muon capture provides a benchmark for the nuclear physics models of neutrinoless double beta decay under comparable momentum transfer conditions. The total capture strength defines the lifetime of the muonic atom. The muon lifetime in $^{76}$Se, the daughter nucleus of $^{76}$Ge, was determined with improved accuracy by the MONUMENT collaboration, using an array of high-purity germanium detectors and a set of scintillator counters at the $π$E1 muon beam line of the Paul Scherrer Institute. The new value of (135.1 $\pm$ 0.5) ns agrees with phenomenological calculations based on the quasiparticle random phase approximation with unquenched axial-vector coupling.

nucl-ex↗

arXiv2025

Direct determination of the $^{235}$U to $^{239}$Pu inverse beta decay yield ratio in the power reactor neutrino experiments

The yields of the inverse beta decay events produced by antineutrinos from a certain nuclear reactor fuel component are used by many experiments to check various model predictions. Yet measurements of the absolute yields feature significant uncertainties coming, mainly, from the understanding of the antineutrino detection efficiency. This work presents a simple novel approach to directly determine the $^{235}$U to $^{239}$Pu inverse beta decay yield ratio using the fuel evolution analysis. This ratio can be used for a sensitive test of reactor models, while the proposed method, results in smaller systematic uncertainties. The DANSS result on this ratio is one of the most precise among reactor neutrino experiments, yet does not significantly contradict to any previous measurement.

nucl-ex↗

arXiv2025

Long term remote reactor power and fuel composition monitoring using antineutrinos

Electron antineutrinos are emitted in the decay chains of the fission products inside a reactor core and could be used for remote monitoring of nuclear reactors. The DANSS detector is placed under the core of the 3.1 GW power reactor at the Kalinin Nuclear Power Plant (KNPP) and collects up to 5000 antineutrino events per day. DANSS measured changes of the reactor power by antineutrino counting rates over 7 years with 1.0% accuracy in one week periods. The fission fractions of four major isotopes for the reactor power calculations were provided by KNPP. The systematic uncertainty of this measurement is less than 0.8%. It is comparable to the accuracy of conventional methods of the reactor power measurements while it is based on completely different approach. For the first time the 239Pu and 235U fission fractions were reconstructed using antineutrino inverse beta-decay spectrum which is a completely new technique. This method was applied to the data from three reactor fuel campaigns (approximately 1.5 year each). The reconstructed fission fractions in about two-week measurements and the fission fractions provided by KNPP coincide within better than 3% accuracy. This provides confidence in both completely different approaches of the fission fraction determination.

hep-ex↗

arXiv2025

New constraints on coherent elastic neutrino-nucleus scattering by the nuGeN experiment

The nuGeN experiment searches for coherent elastic neutrino-nucleus scattering (CEvNS) at the Kalinin Nuclear Power Plant. A 1.41-kg high-purity low-threshold germanium detector surrounded by active and passive shielding is deployed at the minimal distance of 11.1 m allowed by the lifting mechanism from the center of reactor core, utilizing one of the highest antineutrino fluxes among the competing experiments. The direct comparison of the count rates obtained during reactor-ON and reactor-OFF periods with the energy threshold of 0.29~keV$_{ee}$ shows no statistically significant difference. New upper limits on the number of CEvNS events are evaluated on the basis of the residual ON$-$OFF count rate spectrum.

hep-ex↗

arXiv2023

Study of polysterene based scintillator ageing in the DANSS experiment

DANSS is a spectrometer of reactor antineutrino based on plastic scintillator. The sensitive volume of the detector is made of 2500 polystyrene based scintillator plates with wavelength shifting (WLS) fiber readout (strips). We present a study of the strips light yield during 6.5 years of DANSS continuous running. Overall ageing at the rate $0.55 \pm 0.05(syst.)$ % per year is observed that is considerably smaller than in other similar experiments. We also observe the WLS fiber attenuation length shortening at the rate $0.26 \pm 0.04(stat.)$ % per year.

physics.ins-det↗

arXiv2023

Application of the Duperier method to the analysis of the cosmic muon flux dependence on the meteorological parameters, based on the DANSS detector data

The detector DANSS is located under n industrial nuclear reactor at Kalininskaya Nuclear Power Plant. This location provides ~ 50 m.w.e. reduction of the cosmic muon flux in the vertical direction, which places the experiment in an intermediate position between ground and underground experiments in terms of shielding from the cosmic rays. The detector DANSS is located under an industrial nuclear reactor at Kalininskaya Nuclear Power Plant. This location provides ~50 m.w.e. reduction of the cosmic muon flux in the vertical direction, which places the experiment in an intermediate position between ground and underground experiments in terms of shielding from the cosmic rays. The detector's sensitive area consists of 2500 plastic scintillator counters, each 100x4x1 cm$^3$ in size, making in total a 1 m$^3$ volume, which is surrounded by a muon veto system and multiple layers of passive shielding. The main goal of the DANSS experiment is to study the antineutrino spectra at different distances from the source. For this purpose the detector is placed on a lifting platform, and the data is collected at three positions: 10.9 m, 11.9 m and 12.9 m from the center of the reactor core. The detector is capable of reconstructing muon tracks passing though the sensitive volume. In this work the barometric, height and temperature correlation coefficients are calculated in three areas of the zenith angle $θ$ using the Duperier approach. These results are based on the muon data collected during four years.

physics.ins-det↗

arXiv2023

Ordinary muon capture rates on $^{100}$Mo and $^{\rm nat}$Mo for astro-antineutrinos and double beta decays

\item[Background] The nuclear responses for antineutrinos associated with double beta decays (DBDs) and astro-antineutrino interactions are studied by measuring ordinary muon capture (OMC) rates. \item[Purpose]The experimental studies of absolute OMC rates and their mass number dependence for $^{100}$Mo and the natural Mo are currently of interest in astro-antineutrinos and DBDs. \item[Method]The OMC rates were obtained experimentally by measuring the time spectrum of the trapped muon's decay into electrons to obtain the half-lives of the trapped muons. \item[Results]The OMC rate for the enriched isotope of $^{100}$Mo is $Λ$($^{100}$Mo)=(7.07$\pm$0.32)$\times10^{6}$ s$^{-1}$, while that for the natural Mo is $Λ$($^{\rm nat}$Mo)=(9.66$\pm$0.44)$\times10^{6}$ s$^{-1}$, i.e., $Λ$($^{100}$Mo) is about 27$\%$ of $Λ$($^{\rm nat}$Mo), reflecting the blocking effect of the excess neutrons for the proton-to-neutron transformation in OMC. The present experimental observation is consistent with the predictions using Goulard-Primakoff's (GPs) and Primakoff's (Ps) empirical equations. \item[Conclusions] The absolute OMC rates for $^{100}$Mo and $^{\rm nat}$Mo were measured. The large neutron excess in $^{100}$Mo gives a much lower OMC rate than $^{\rm nat}$Mo. On both $^{100}$Mo and $^{\rm nat}$Mo, consistent OMC rates with the GP and P values are observed.

nucl-ex↗

arXiv2022

First results of the nuGeN experiment on coherent elastic neutrino-nucleus scattering

The nuGeN experiment is aimed to investigate neutrino properties using antineutrinos from the reactor of the Kalinin Nuclear Power Plant. The experimental setup is located at about 11 meters from the center of the 3.1 GWth reactor core. Scattering of the antineutrinos from the reactor is detected with low energy threshold high purity germanium detector. Passive and active shieldings are used to suppress all kinds of backgrounds coming from surrounding materials and cosmic radiation. The description of the experimental setup together with the first results is presented. The data taken in regimes with reactor ON (94.50 days) and reactor OFF (47.09 days) have been compared. No significant difference between spectra of two data sets is observed, i.e. no positive signals for coherent elastic neutrino-nucleus scattering are detected. Under Standard Model assumptions about coherent neutrino scattering an upper limit on a quenching parameter k < 0.26 (90 \% C.L.) in germanium has been set.

nucl-ex↗

arXiv2022

Observation of the temperature and barometric effects on the cosmic muon flux by the DANSS detector

The DANSS detector 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 $\langle E_{thr}\cosθ\rangle$ and $\langle E_{thr} \rangle$, 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.

physics.ins-det↗

arXiv2022

Optimized scintillation strip design for the DANSS upgrade

DANSS is a one cubic meter plastic scintillator detector with a primary goal of the sterile neutrino searches at a commercial nuclear reactor. Due to its highly advantageous location, fine segmentation and ability to change the distance to the neutrino production origin DANSS is ahead of many similar experiments around the world in terms of the counting rate, signal to background ratio and sterile neutrino exclusion regions. Yet a moderate energy resolution of the detector prevents the further progress in the physics program. The main challenge of the planned upgrade is to achieve the energy resolution of 12% at 1 MeV. The new design of the main sensitive element - the plastic scintillation strip - is the most important step forward. The strip prototypes were manufactured and tested at the pion beam of the PNPI synchrocyclotron. More than twice higher light output together with fairly flat detector response uniformity, longitudinal timing information and other optimizations will surely help to reach the upgrade goal. The paper discusses the drawbacks of the current strip version, outlines the new features of the proposed upgrade, describes the beam test procedure and presents the test results reflecting the advantages of the new strip design in comparison with the currently used version.

physics.ins-det↗

arXiv2018

Search for sterile neutrinos at the DANSS experiment

DANSS is a highly segmented 1~m${}^3$ 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~$\mathrm{GW_{th}}$ 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 $\widetildeν_e$ per day at the closest position with the cosmic background less than 3$\%$. The inverse beta decay process is used to detect $\widetildeν_e$. Sterile neutrinos are searched for assuming the $4ν$ model (3 active and 1 sterile $ν$). The exclusion area in the $Δm_{14}^2,\sin^22θ_{14}$ 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 $\widetildeν_e$ spectrum, as well as on the detector efficiency. Results are based on 966 thousand antineutrino events collected at 3 distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters up to $\sin^22θ_{14}<0.01$ in the most sensitive region.

hep-ex↗

arXiv2016

Characterisation of Medipix3 Silicon Detectors in a Charged-Particle Beam

While designed primarily for X-ray imaging applications, the Medipix3 ASIC can also be used for charged-particle tracking. In this work, results from a beam test at the CERN SPS with irradiated and non-irradiated sensors are presented and shown to be in agreement with simulation, demonstrating the suitability of the Medipix3 ASIC as a tool for characterising pixel sensors.

physics.ins-det↗