In modern technological processes, a large role is played by measurements of technical parameters. The total number of industrial enterprises is constantly monitored by regulatory authorities for the ...use of water resources. Mostly it was not possible to measure most of the existing pressure-free flows recently, but with the advent of equipment on the metrology market that could measure the speed and level at the same time, the situation changed radically. It makes sense to consider in detail two measurement methods that are currently used in more than 90 % of cases - the acoustic (non-contact) method and the two-channel Doppler method which metrological standards of these methods were compared.
The progress in the development of the GERDA (GErmanium Detector Array) experiment is presented. The goal of the experiment is the search for neutrinoless double beta decay of 76Ge with considerable ...reduction of background in comparison with predecessor experiments. GERDA will operate bare germanium semiconductor detectors (enriched in 76Ge) submerged in high purity liquid argon supplemented by a water shield. The experimental set up is currently under construction in the underground facility of LNGS, Italy. The results of various R&D efforts and the main steps of the GERDA set up design and installation are given as well as several novel methods for background reduction are described.
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 researches of the structural and magnetic properties of the layered chalcogenide Fe
4
Co
3
Se
8
, which has a ferrimagnetic order below
T
= 196 K, have been performed by means of X-ray ...diffraction, magnetic susceptibility measurements, and
59
Co nuclear magnetic resonance (NMR) spectroscopy. It is found that the effective magnetic moment of iron ions is μ
eff
≈ 5.90(5) μ
B
. The components of the magnetic shift and electric field gradient tensors at the Co nuclei sites have been determined. The hyperfine field induced on Co nuclei from neighboring iron ions has been estimated from the temperature dependences of the shift and susceptibility in Fe
4
Co
3
Se
8
. It was also established that cobalt ions in Fe
4
Co
3
Se
8
, as well as in the Co
7
Se
8
compound, do not have intrinsic magnetic moment, but they do have a moment induced from neighboring iron ions
≈ 0.36(4) μ
B
, which decreases at the magnetic ordering to 0.07(1)μ
B
due to mutual compensation of contributions from neighboring iron ions.
For the first time, an
93
Nb NMR study of dichalcogenides Cr
x
NbSe
2
(
x
= 0.33, 0.5) in the paramagnetic state was performed. Analysis of the
93
Nb NMR spectra revealed the presence in Cr
x
NbSe
2
...of three magnetically nonequivalent niobium positions, whose immediate environment contains 0, 1, and 2 chromium ions, respectively. For each Nb position with a different number of chromium atoms in the immediate environment in Cr
x
NbSe
2
(
x
= 0.33, 0.5), the values of the components of the magnetic shift and electric field gradient tensors at the position of the niobium nuclei were determined. Evidence was obtained of the formation in Cr
0.33
NbSe
2
of the ordering of chromium ion positions in the
ab
plane into a
a
0
×
a
0
superstructure. On the other hand, in Cr
0.5
NbSe
2
, no obvious indications of the formation of any superstructure of chromium ion positions were found. It has been established that the overlap of the 4
d
and 5
s
shells of niobium ions and the 3
d
orbitals of chromium leads to the appearance of a positive hyperfine field induced by the magnetic moments of chromium on Nb nuclei. From the temperature dependences of the shift and susceptibility in Cr
0.5
NbSe
2
, an estimate of these induced hyperfine fields is made.
Wide Temperature Range Fiber Optic Sensor Konin, Y. A.; Petrov, A. A.; Starikova, V. A. ...
Bulletin of the Russian Academy of Sciences. Physics,
2022/12, Letnik:
86, Številka:
Suppl 1
Journal Article
Recenzirano
Currently, fiber Bragg gratings are the main type of sensor structure in fiber optic sensors. However, during their creation the protective-strength coating is removed, which reduces the strength and ...flexibility of the fiber and limits the field of application of such sensors. A solution to this problem could be the creation of a fiber-optic sensor using a new technology in which the protective-strength coating is not damaged, and the sensor structure is created using a fusion effect. When recording the sensor structure in a given area of the fiber, the conditions for generating a plasma focus are created, after the passage of which a structure of microneedles of various shapes is formed. Sensors created using such technology can operate in a wide temperature range. The aim of the present study is to determine the dependence of changes in the spectral characteristics of the sensor in the temperature range from 4 to 700 K.
Fiber Optic Sensor for Cryogenic Liquids Konin, Y. A.; Petrov, A. A.; Perminov, A. V. ...
Bulletin of the Russian Academy of Sciences. Physics,
06/2024, Letnik:
88, Številka:
6
Journal Article
Recenzirano
Classical fiber optic physical sensors have intra-fiber structures that change the back-reflection response as environmental conditions change. These structures are often a modification of the fiber ...core glass. But, there are sensors that are the incorporation of a gas or liquid cell into the fiber core. Such a structure works as a Fabry–Pérot interferometer, it can also work as a threshold sensor when the aggregate state of the cell changes. This paper deals with the structure in the fiber created by the fuse effect. The cells of this structure contain oxygen at pressures from 4 atm. These cells work as a threshold sensor that can indicate the presence of cryogenic liquid. The purpose of the present study is to determine the dependence of the change in back reflection on temperature.
The
63
Cu and
27
Al NMR spectra have been obtained on a polycrystalline CuAlO
2
sample in external magnetic field
H
0
= 92.8 kOe in temperature range 30–400 K. Analysis of the
27
Al NMR spectra has ...revealed that with temperature decrease, the NMR line shift
27
K
increases in magnitude and can be described by the Curie–Weiss law. Such a behavior can be attributed to the emergence of an effective magnetic moment at copper ions due to the motion of holes in the copper sublattice. In the low-temperature range, the maximum of the spin–lattice relaxation rate
of
27
Al nuclei is observed, which is most probably induced by thermally activated diffusion of holes. Analysis of experimental data on
yields an estimate
E
a
≈ 0.1–0.2 eV for the activation energy. The temperature dependences of the quadrupole interaction parameters indicate the crystal lattice compression along the
a
and
c
axes.
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