Results of a search for the masked regularities in the
Po
-active isotope half-life solar-daily variation parameters in the data collected during 2012–2015 years are presented. It is shown, that an ...amplitude of a sinusoidal function approximating half-life solar-daily dependence obtained by averaging data during 90 days for each season of the years could reach
from the average daily value. Similar analysis of the
Po data collected in 2018–2022 years shows that amplitude of the deviation from the average value could reach
. This effect limits an accuracy of the high precision measurements with this or similar short-lived isotopes generating systematic errors if the data were collected during a relatively short time. The new value of the
Po half-life which is
Po
s was obtained on the base of the data collected during 2018–2022 years.
Resonance excitation of the
83
Kr first nuclear level (
E
= 9.4 keV) by solar axions formed via the Primakoff mechanism is sought. The γ- and X-ray photons and the conversion and Auger electrons ...arising from the excited-level relaxation are detected with a gas proportional counter of a low-background detector in the underground Baksan Neutrino Observatory. The following experimental constraint is obtained for the product of the axion–photon coupling constant and the axion mass:|
g
A
γ
×
m
A
| ≤ 6.3 × 10
-17
In the framework of the hadronic-axion model, this corresponds to a new axion-mass constraint of
m
A
≤ 12.7 eV at 95% C.L.
The resonant excitation of the
83
Kr first excited nuclear level (
E
= 9.4 keV) by solar axions whose fluxes depend on the axion–electron coupling constant
g
Ae
is sought. The γ- and X-ray photons ...and the conversion and Auger electrons from the excited-level relaxation are detected with a gas proportional counter of a low-background detector in the underground Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences). As a result, a new constraint
≤ 1.50 × 10
–17
(90% C.L.) has been obtained for the axion–electron and axion–nucleon coupling constants, which corresponds to new constraints on the axion mass
m
A
≤ 320 eV and
m
A
≤ 4.6 eV in the KSVZ and DFSZ axion models, respectively.
Working characteristics of the New Low-Background Laboratory (DULB-4900) Gavriljuk, Ju.M.; Gangapshev, A.M.; Gezhaev, A.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2013, Letnik:
729
Journal Article
Recenzirano
Odprti dostop
The Baksan Neutrino Observatory of the Institute for Nuclear Research of the Russian Academy of Science is one of the first and biggest underground laboratories in the world specially constructed to ...carry out different types of experiments in the field of nuclear physics, particle and astroparticle physics. Main technical characteristics of the new low-background laboratory DULB-4900 of the BNO are presented. The laboratory is located at a distance of 3700m from the main entrance of the observatory tunnel in the hall with dimensions ~6×6×40m3. Thickness of the mountain rock over DULB corresponds to 4900m w.e. and this deep location provides the cosmic ray flux reduction with the factor of about 107. The methods and results of the background level measurements both in the hall and operating facilities are given. Contamination of the radioactive 222Rn gas has been also measured in the air by using direct detection of γ-radiation of its daughter 214Bi distributed inside the volume of the low-background chamber. The results of the data analysis are presented and discussed.
•Main technical characteristics of the new unique Deep Underground Low Background laboratory of the Baksan Neutrino Observatory are presented.•The rock overburden of 4900m w.e. reduces the cosmic muon flux down to about (3.0±0.15)×109muonscm−2s−1.•The methods and results of the background level measurements both in the hall and operating facilities are given.
The concentrations of the gases
12
CO
2
,
13
CO
2
, СН
4
, and Н
2
О and the trends of Earth degassing under changing atmospheric pressure were analyzed remotely for the first time using a ...differential absorption lidar. To reduce the influence of external meteorological factors, the sensing was carried out in a dead-end tunnel of the Baksan Neutrino Observatory of the Institute for Nuclear Research, Russian Academy of Sciences.
The CUP array of germanium (CAGe) is an array of fourteen high-purity germanium (HPGe) detectors. The detection efficiency of full-energy-peak emitted from the various samples assayed on the CAGe was ...calculated using the Monte Carlo simulation toolkit GEANT4. If the dead layer on the surface of the crystal is treated in the simulation as a continuous part of the active crystal, then the detection efficiency will be overestimated. Thus, the detection efficiency of the CAGe was adjusted using multi-nuclide source data and Monte Carlo simulations. The gamma spectra of the known activity source were obtained for each HPGe detector of the CAGe. The detection efficiency measured by the multi-source data was smaller than that of simulation data if the simulation treated the whole volume of germanium crystals as active for gamma detection. By optimizing the dead layers’ thicknesses in the simulation, the detection efficiency calculated by the simulation could be matched to that of multi-source data.
•Detection efficiency of an array of fourteen HPGe detectors was adjusted using Monte Carlo simulation and multi-source data.•Eleven gamma energy peaks emitted from multi-source are used for the detection efficiency calibration.•Good agreement between simulation and measurement is found by dead layer thickness optimizing in GEANT4 simulation geometry.
In this paper, the results of lidar monitoring of magmatic aerosol variation are presented. The lidar was installed in a hot dead-end tunnel at the end of the auxiliary adit of the Baksan Neutrino ...Observatory (BNO) of the Institute for Nuclear Research, Russian Academy of Sciences, which is located above the small magma chamber of the Elbrus Volcanic Center. A sharp (within ~30 min) threefold increase in the aerosol concentration in the hot tunnel was detected (October 28, 2019, 22:30 UTC). The analysis involved data on volumetric radon activity, air temperature, and humidity. A synchronous increase in temperature, humidity, and aerosol concentration in the tunnel, as well as their correlation with the deformation of the Earth’s crust by tidal waves, which is monitored at the BNO with a laser strainmeter, was revealed. However, the threefold jump did not appear in these signals. The totality of data confirms the existence of a hot magma chamber at the base of Mount Andyrchi that was previously discovered by a small-aperture seismometer group. The assumption that the release of gases from the magma chamber could provide a jump in the concentration of aerosols without disturbing other parameters is discussed.
The article reports on the current status of the Baksan Large Neutrino Telescope project and describes some selective results of the first stage of the project, a detector prototype with a liquid ...scintillator mass of 0.5 tons. The results of the second stage of the project, a prototype with liquid scintillator mass of 5 tons, and project prospects also presented.
The energy resolution is calculated for a neodymium-containing liquid organic scintillation detector (Nd-OS) with a volume of several liters to search for neutrinoless double beta decay of
150
Nd as ...a function of the neodymium concentration up to 5 g/L. The results are presented in detailed tables and graphs.
The study of low-yield effects requires not only good quality of the original data but also puts high requirements for their processing procedures to increase the efficiency of the selection of ...useful events. The exploiting of the large cylindrical proportional counter's electrostatic topology allows improving the extrapolation of information about the primary ionization of a multipoint event. Long-term calibration measurements with an external 109Cd-source allowed the development of a new method for analyzing the pulse shape from a sizeable proportional counter. Optimized analysis of the current's pulse shape from the electron cloud of primary ionization in the counter improved the resolution and energy calibration. As a result, the efficiency of selecting useful events was increased by 25%.
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