The Tunka-133 EAS Cherenkov light array: Status of 2011 Berezhnev, S.F.; Besson, D.; Budnev, N.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2012, Letnik:
692
Journal Article
Recenzirano
Odprti dostop
A new EAS Cherenkov light array, Tunka-133, with ∼1km2 geometrical area has been installed at the Tunka Valley (50km from Lake Baikal) in 2009. The array permits a detailed study of cosmic ray energy ...spectrum and mass composition in the energy range 1016–1018eV with a uniform method. We describe the array construction, DAQ and methods of the array calibration. The method of energy reconstruction and absolute calibration of measurements are discussed. The analysis of spatial and time structure of EAS Cherenkov light allows to estimate the depth of the EAS maximum Xmax.
The results on the all particles energy spectrum and the mean depth of the EAS maximum Xmax vs. primary energy derived from the data of two winter seasons (2009–2011) are presented. Preliminary results of joint operation of the Cherenkov array with antennas for the detection of EAS radio signals are shown. Plans for future upgrades – deployment of remote clusters, radioantennas and a scintillator detector network and a prototype of the HiSCORE gamma-telescope – are discussed.
The EAS Cherenkov light array Tunka-133, with ~ 3 km2 geometric area, is taking data since 2009.The array permits a detailed study of energy spectrum and mass composition of cosmic rays in the ...energy range from 6 · 1015 to 1018 eV. We describe the methods of time and amplitude calibration of the array and the methods of EAS parameters reconstruction. We present the all-particle energy spectrum, based on 7 seasons of operation.
Oxygen non-stoichiometry, electrical conductivity and thermal expansion of La2-xSrxNiO4-delta phases with high levels of strontium-substitution (1 < = x < = 1.4) have been investigated in air and ...oxygen atmosphere in the temperature range 20-1050 deg C. These phases retain the K2NiF4-type structure of La2NiO4 (tetragonal, space group I4/mmm). The oxygen vacancy fraction was determined independently from thermogravimetric and neutron diffraction experiments, and is found to increase considerably on heating. The electrical resistivity, thermal expansion and cell parameters with temperature show peculiar variations with temperature, and differ notably from La2NiO4+/-delta in this respect. These variations are tentatively correlated with the evolution of nickel oxidation state, which crosses from a Ni3+/Ni4+ to a Ni2+/Ni3+ equilibrium on heating.
The Tunka-Grande array is part of an experimental complex located in the Tunka Valley (Republic of Buryatia, Russia) about 50 km from Lake Baikal. This complex also contains the Tunka-133 and ...Tunka-Rex arrays. The aim of this complex is to study the primary cosmic ray energy spectrum and mass composition in the energy range of 10
16
–10
18
eV, and to search for diffuse gamma rays in the energy range of 5 × 10
16
–5 × 10
17
eV. The design of the Tunka-Grande array and the procedure for reconstructing the parameters of extensive air showers (EASes) are described, and preliminary results are presented from the search for diffuse gamma rays with energies of more than 5 × 10
16
eV.
The Advanced Laser Interferometer Gravitational-Wave Observatory and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst ...that followed the merger of this binary was also recorded by Fermi gamma-ray burst monitor and International Gamma-Ray Astrophysics Laboratory, indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the energy range of 1 TeV–100 PeV using the Baikal Gigaton Volume Detector. No neutrinos directionally coincident with the source were detected within ±500 s around the merger time, as well as during a 14-day period after the gravitational wave detection. We derived 90% C.L. upper limits on the neutrino fluence from GW170817 during a ±500 s window centered on the gravitational wave trigger time, and a 14-day window following the gravitational wave signal under the assumption of an
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−2
neutrino energy spectrum.
The study of the cosmic ray mass composition in the energy range 1016 - 1018 eV is one of the main aims of Tunka-133. This EAS Cherenkov array started data acquisition in the Tunka Valley (50 km from ...Lake Baikal) in autumn 2009. Tunka-133 provides a measurement of the EAS maximum depth (Xmax) with an accuracy of about 30 g/cm2. Further mass composition analyses at the highest energies (1017 - 1018 eV) will be based on the comparison of primary energy measured by the radio method and the densities of charged particles measured by shielded and unshielded detectors. The high duty cycle of the common operation of the new scintillation array (Tunka-Grande) and the radio extension of the experiment (Tunka-REX) will provide a high statistics of events.
A method is proposed for assessing the seismic resistance of soils, involving the analysis of seismic data (with soil conditions taken into account), the choice and specification of ...amplitude–frequency spectrum parameters, experimental studies of soil samples with specified cyclic load parameters, analysis of the dependence of soil behavior on the overload factor, and calculating the ultimate overload factor based on the comparison of accepted and ultimate effect levels. The paper gives the results of practical application of the developed approach to assessing the seismic resistance of a shelf area in the Northern Caspian Sea.
Tunka-133: Results of 3 year operation Prosin, V.V.; Berezhnev, S.F.; Budnev, N.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2014, Letnik:
756
Journal Article
Recenzirano
Odprti dostop
The EAS Cherenkov light array Tunka-133, with ~3km2 geometric area, is taking data since 2009. The array permits a detailed study of cosmic ray energy spectrum and mass composition in the PeV energy ...range. After a short description of the methods of EAS parameter reconstruction, we present the all-particle energy spectrum and results of studying CR composition, based on 3 seasons of array operation. In the last part of the paper, we discuss possible interpretations of the obtained results.
The prototyping/early construction phase of the BAIKAL-GVD project Avrorin, A.D.; Avrorin, A.V.; Aynutdinov, V.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2014, Letnik:
742
Journal Article
Recenzirano
Odprti dostop
The prototyping phase of the BAIKAL-GVD project has been started in April 2011 with the deployment of a three string engineering array which comprises all basic elements and systems of the Gigaton ...Volume Detector (GVD) in Lake Baikal. In April 2012 the version of engineering array which comprises the first full-scale string of the GVD demonstration cluster had been deployed and operated during 2012. The first stage of the GVD-cluster which consists of three strings was deployed in April 2013. We review the prototyping phase of the BAIKAL-GVD project and describe the configuration and design of the 2013 engineering array.
One of the crack resistance characteristics of carbon fiber reinforced plastics (CFRPs) is fracture toughness, which is the change in the elastic deformation energy of the structural element upon the ...increase in the crack area by unity at the crack onset. By studying fracture toughness, the position of the front of the crack is determined: both initial and during its growth. Currently existing test standards (STO TsAGI, ASTM D7905) determine fracture toughness by the
G
II
c
shear mode on the samples with a crack initiator. However, the method does not reflect the real conditions of crack initiation in structures of CFRPs and can lead to a decrease in the accuracy of determining the load of crack onset. A new technique of fracture toughness determination of CFRPs in the
G
II
c
shear mode on samples free of the standard delamination initiator has been developed at TsAGI. The aim of this work is to perform studies for developing the proposed technique. The
G
II
c
values were determined for a shear crack that occurred under three-point bending conditions after wedging. To determine the position and shape of the crack front, as well as to estimate the dynamics of its propagation under subsequent loads, we used ultrasonic methods: ultrasonic flaw detection (ultrasonic NDT) and acoustic microscopy. It is shown that acoustic microscopy at a frequency of 50 MHz makes it possible to determine the crack front position in CFRP samples at a depth of 3.0–3.5 mm with a high resolution of about 100 μm. The features of the crack growth under shear conditions are discussed. The results of the study show that high accuracy of acoustic microscopy in comparison with conventional ultrasonic testing is eagerly sought for determining the crack shape, as well as for analyzing the dynamics of crack growth and revealing the mechanisms of interlaminar crack propagation in a composite material.
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