arXiv subjects

Yu. M. Gavrilyuk

Publications and source records attributed to Yu. M. Gavrilyuk.

24 records · Page 2Linked to original sources

arXiv2015

Results of a search for daily and annual variations of the Po-214 half-life at the two year observation period

The brief description of installation TAU-2 intended for long-term monitoring of the half-life value $τ$ ($τ_{1/2}$) of the $^{214}$Po is presented. The methods of measurement and processing of collected data are reported. The results of analysis of time series values $τ$ with different time step are presented. Total of measurement time was equal to 590 days. Averaged value of the $^{214}$Po half-life was obtained $τ=163.46\pm0.04$ $μ$s. The annual variation with an amplitude $A=(8.9\pm2.3)\cdot10^{-4}$, solar-daily variation with an amplitude $A_{So}=(7.5\pm1.2)\cdot10^{-4}$, lunar-daily variation with an amplitude $A_L=(6.9\pm2.0)\cdot10^{-4}$ and sidereal-daily variation with an amplitude $A_S=(7.2\pm1.2)\cdot10^{-4}$ were found in a series of $τ$ values. The maximal values of amplitude are observed at the moments when the projections of the installation Earth location velocity vectors toward the source of possible variation achieve its maximal magnitudes.

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arXiv2015

New limit on the mass of 9.4-keV solar axions emitted in an M1 transition in $^{83}$Kr nuclei

A search for resonant absorption of the solar axion by $^{83}\rm{Kr}$ nuclei was performed using the proportional counter installed inside the low-background setup at the Baksan Neutrino Observatory. The obtained model independent upper limit on the combination of isoscalar and isovector axion-nucleon couplings $|g_3-g_0|\leq 1.69\times 10^{-6}$ allowed us to set the new upper limit on the hadronic axion mass of $m_{A}\leq 130$ eV (95\% C.L.) with the generally accepted values $S$=0.5 and $z$=0.56.

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arXiv2014

First result of the experimental search for the 9.4 keV solar axion reactions with Kr-83 in the copper proportional counter

The experimental search for solar hadronic axions is started at the Baksan Neutrino Observatory of the Institute for Nuclear Researches Russian Academy of Science. It is assumed that axions are created in the Sun during M1-transition between the first thermally excited level at 9.4 keV and the ground state in Kr-83. The experiment is based on axion detection via resonant absorption process by the same nucleus in the detector. The big copper proportional counter filled with krypton is used to detect signals from axions. The experimental setup is situated in the deep underground low background laboratory. No evidence of axion detection were found after the 26.5 days data collection. Resulting new upper limit on axion mass is m_{A} < 130 eV at 95% C.L.

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arXiv2014

Sources of the systematic errors in measurements of Po-214 decay half-life time variations at the Baksan deep underground experiments

The design changes of the Baksan low-background TAU-1 and TAU-2 set-ups allowed to improve a sensitivity of Po-214 half-life (τ) measurements up to the 2.5 x 10^{-4} are described. Different possible sources of systematic errors influencing on the $τ$-value are studed. An annual variation of Po-214 half-life time measurements with an amplitude of A=(6.9 \pm 3) x 10^{-4} and a phase of (ϕ=93 \pm 10) days was found in a sequence of the week-collected τ-values obtained from the TAU-2 data sample with total duration of 480 days. 24 hours' variation of the τ-value measurements with an amplitude of A=(10.0 \pm 2.6) x 10^{-4} and phase of (ϕ=1 \pm 0.5) hours was found in a solar day 1 hour step τ-value sequence formed from the same data sample. It was found that the Po-214 half-life averaged at 480 days is equal to (163.45 \pm 0.04) mks.

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arXiv2014

First result of the experimental search for the 2K-capture of Xe-124 with the copper proportional counter

First result of experiment for searching of 2K-capture of Xe-124 with the large-volume copper proportional counter is given. The 12 litre sample with 63.3% (44 g) of Xe-124 was used in measurements. The limit on the half-life of Xe-124 with regard to 2K(2ν)-capture for the ground state of Te-124 has been found: T_{1/2} > 4.67x10^{20} y (90% C.L.). A sample with volume 52 L comprising of Xe-124 (10.6 L - 58.6 g) and Xe-126 (14.1 L - 79.3 g) will used at the next step of the experiment to increase a sensitivity of 2K-caption of Xe-124 registration. In this case sensitivity to the investigated process will be at the level of S=1.46 x 10^{21} y (90% C.L.) for 1 year measurement.

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arXiv2010

Results of wavelet processing of the 2K-capture Kr-78 experiment statistics

Results of a search for Kr-78 double K-capture with the large low-background proportional counter (2005-2008 years) at the Baksan Neutrino Observatory are presented. An experimental method and characteristics of detectors are described. Basic features of the digitized pulses processing using wavelet transform are considered. With due account taken of the analysis of individual noise characteristic it has been shown that the appropriate choice of both wavelet characteristics and sequence of processing algorithms allows one to decrease the background in the energy region of useful events with a unique set of characteristics by ~2000 times. New limit on the half-life of Kr-78 with regard to 2K-capture has been found: T_{1/2} >= 2.4E21 yrs (90% C.L.).

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