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
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.
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.
Using the semi-empirical quantum chemical PM3 method the energies of carbon nanoscrolls formed from flat zigzag graphene nanoribbons 46zGNR and 70zGNR are calculated. For this purpose a simple ...algorithm to define the Cartesian coordinates of the atoms of a carbon nanoscroll is proposed. The dependences of the energy of the nanoscrolls relative to the energy of the corresponding flat nanoribbon on the inner radius of nanoscroll obtained using both the quantum chemical calculations and the semi-classical analytical model shows the bistability of the system. This shows promise for nanoscroll-based nanoelectromechanical systems.
The advanced molybdenum-based rare process experiment (AMoRE) aims to search for neutrinoless double beta decay (
0
ν
β
β
) of
100
Mo with
∼
100
kg
of
100
Mo-enriched molybdenum embedded in cryogenic ...detectors with a dual heat and light readout. At the current, pilot stage of the AMoRE project we employ six calcium molybdate crystals with a total mass of 1.9 kg, produced from
48
Ca-depleted calcium and
100
Mo-enriched molybdenum (
48
depl
Ca
100
MoO
4
). The simultaneous detection of heat (phonon) and scintillation (photon) signals is realized with high resolution metallic magnetic calorimeter sensors that operate at milli-Kelvin temperatures. This stage of the project is carried out in the Yangyang underground laboratory at a depth of 700 m. We report first results from the AMoRE-Pilot
0
ν
β
β
search with a 111 kg day live exposure of
48
depl
Ca
100
MoO
4
crystals. No evidence for
0
ν
β
β
decay of
100
Mo is found, and a upper limit is set for the half-life of
0
ν
β
β
of
100
Mo of
T
1
/
2
0
ν
>
9.5
×
10
22
years
at 90% C.L. This limit corresponds to an effective Majorana neutrino mass limit in the range
⟨
m
β
β
⟩
≤
(
1.2
-
2.1
)
eV
.
The structure of a new metamaterial with negative permittivity and permeability that is made of periodically positioned graphene/boron nitride nanoscrolls and carbon nanotubes is proposed. The ...parameters of the metamaterial structure with a negative refractive index for the frequency of an electromagnetic wave within the visible range (namely, from near infrared to yellow) are calculated.
We review the principles of formation, physical properties, and current or envisaged applications for a wide range of carbon allotropic forms. We discuss experimental and theoretical advances ...relating to staple zero-, one-, and two-dimensional carbon structures, such as fullerenes, carbon nanotubes, and graphene. In addition we emphasize research on emerging carbon allotropes (carbon nanoscrolls, funnels, etc) that result from combining or deforming allotropic forms with well-defined dimensionality. Such materials fall in-between clearly delineated dimensional categories and consequently exhibit unique characteristics that are promising for electronic, optical, and mechanical applications. We also consider other approaches to tuning properties of carbon-based materials, such as chemical functionalization, intentional introduction of structural disorder, and placement of guest atoms or molecules inside hollow structures. Finally, we discuss the properties of and experimental methods for studying zero-dimensional systems (paramagnetic nitrogen impurity atoms) in diamond matrix. The review emphasizes the interplay between the various material properties of carbon-based nanostructures and the designs for nanoscale devices that rely on synergistic combinations of these properties. For example, an electromechanical vibrator, a strain sensor, a nanodynamometer, and a nanoelectromechanical memory cell that we describe exploit both electronic and nanomechanical properties of low-dimensional carbon structures, a reed switch and a magnetic field sensor use magnetic and nanomechanical properties, a maser based on nitrogen-doped diamond uses thermal and optoelectronic properties, etc. All presented device concepts have been validated by calculations, and some have been implemented experimentally.
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%.
Abstract
The article provides a comprehensive assessment of environmental management in waste management: environmental pollution due to an increase in waste disposal volumes, operation of ...environmentally hazardous waste, ash deposition, a low level of involvement of recycled waste disposal sites as a valuable secondary resource in economic circulation. The process of processing ash waste from coal-fired TPPs has been investigated as an aspect of environmental safety. Today’s planners are working to develop a waste management strategy for waste ash from coal-fired power plants in order to find out how to properly and efficiently use the waste. As a result of their efforts, fly ash is used very effectively and economically in construction technology, agriculture, etc.
PDF
