The use of mechanochemical activation of the powder at the stage of mixing the components and consolidation by spark plasma sintering made it possible to synthesize material based on silicon carbide, ...which has a weight loss of less than 0.04% when tested for heat resistance at 1500°C for 100 h. A ceramic material was produced at a consolidation temperature of 1800°C, its hardness was 32 GPa and a critical stress intensity factor was 6 MPa m
1/2
.
Consolidation of commercial silicon carbide powder was performed by means of spark plasma sintering. It is shown that mechanical preactivation is a promising method for introducing a high content of ...boron additives into silicon carbide. The effect of the boron-additive amount on sintering, microstructure, and properties of the ceramic material was studied. A ceramic showing promise for use as a structural material in nuclear reactors and gas-turbine engines was obtained on the basis of silicon carbide with boron weight content 10%, density 3.12 g/cm
3
, hardness 31.9 GPa, and crack resistance 5.65 MPa·m
1/2
.
Industrial silicon carbide powder was consolidated with boron by the spark-plasma-sintering (SPS) method. It was shown that a preliminary mechanical activation is a promising method for introduction ...of high concentrations of boron into silicon carbide. The influence exerted by the boron concentration on the sintering and properties of the material based on silicon carbide was examined. A ceramic based on silicon carbide with 10 wt % amorphous boron was obtained with density of 3.12 g cm
–3
, hardness of 31.9 GPa, and crack-resistance coefficient of 5.7 MPa m
1/2
. The ceramic is promising as a construction ceramic for nuclear reactors and gas-turbine engines.
The article presents the relevance and advantages of the new gamma observatory TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy), which is being constructed in the Tunka ...Valley 50 km from Lake Baikal. Various detectors of the six TAIGA gamma observatory arrays register the Cherenkov and radio radiation, as well as the electron and muon components of EAS. The primary objective of the TAIGA gamma observatory is to study the high-energy part of the gamma-ray spectrum, in particular, in order to search for Galactic PeVatrons. The energy, direction, and position of the EAS axis are reconstructed in the observatory based on the data of the wide-angle Cherenkov detectors of the TAIGA-HiSCORE experiment. Taking into account this information, the gamma quanta are distinguished from the hadron background using the data obtained by the muon detectors and telescopes that register the EAS image in the Cherenkov light. In this hybrid mode of operation, the atmospheric Cherenkov telescopes can operate in the mono-mode, and the distance between them can be increased to 800–1000 m, which makes it possible to construct an array with an area of 5 km
2
and more at relatively low cost and in a short time. By 2019, the first stage of the gamma observatory with an area of 1 km
2
will be constructed; its expected integral sensitivity for detecting the gamma radiation with an energy of 100 TeV at observation of the source for 300 hours will be approximately
10
–13
TeV cm
–2
s
–1
.
—
The paper is devoted to the modeling and analysis of data detected by the TAIGA-IACT installation in the stereo mode. Five Imaging Atmospheric Cherenkov Telescopes (IACT) with a viewing angle of ...9.6° are expected to be included in the installation. Today there are three telescopes spaced far apart (from 320 to 500 m) in the installation. The effective area of the installation is as large as 0.6 km
2
; therefore, it is possible to conduct statistically significant measurements of weak γ-ray sources in the energy range above 10 TeV over a reasonable observation time (300–400 h). The Monte Carlo procedure for simulating the hadrons and γ-rays detected by the telescopes is described as is the procedure for reconstructing the parameters of extensive air showers, such as the arrival direction of an event, the axis position, the depth of the maximum of shower development (
X
max
), and the primary-particle energy. In order to solve the problem of γ-hadron separation, the criteria for selecting γ-rays detected in the stereo mode have been optimized and the effective area of the installation has been calculated.
Status and First Results of TAIGA Tluczykont, M.; Astapov, I. I.; Awad, A. K. ...
Physics of atomic nuclei,
11/2021, Letnik:
84, Številka:
6
Journal Article
Recenzirano
The Tunka Advanced Instrument for Gamma-ray and cosmic ray Astrophysics (TAIGA) is a hybrid experiment for the measurement of Extensive Air Showers (EAS) with good spectral resolution in the TeV to ...PeV energy range. In this domain, the long-sought Pevatrons can be detected. Currently the TAIGA detector complex combines a two wide angle shower front Cherenkov light sampling timing arrays (HiSCORE and Tunka-133), two 4 m class, 10
aperture Imaging Air Cherenkov Telescopes (IACTs) and 240 m
surface and underground charged particle detector stations. Our goal is to introduce a new hybrid reconstruction technique, combining the good angular and shower core resolution of HiSCORE with the gamma-hadron separation power of imaging air Cherenkov telescopes. This approach allows to maximize the effective area and simultaneously to reach a good gamma-hadron separation at low energies (few teraelectronvolts). At higher energies, muon detectors are planned to enhance gamma-hadron separation. During the commissioning phase of the first and second IACT, several sources were observed. First detections of known sources with the first telescope show the functionality of the TAIGA IACTs. Here, the status of the TAIGA experiment will be presented, along with first results from the current configuration.
The change in the Gibbs energy of reactions where SiC interacts with oxides of different nature in the temperature range from 298 to 2300 K is calculated and analyzed for the purpose of picking ...modifiers for obtaining structural ceramics from SiC. On the basis of the obtained data CaO, MgO, SrO, Al
2
O
3
, Y
2
O
3
, Sc
2
O
3
, and lanthanide oxides can be recommended for the synthesis of modifiers in energy-efficient silicon-carbide ceramic technologies.
ABSTRACT
The existence of high-energy astrophysical neutrinos has been unambiguously demonstrated, but their sources remain elusive. IceCube reported an association of a 290-TeV neutrino with a ...gamma-ray flare of TXS 0506 + 056, an active galactic nucleus with a compact radio jet pointing to us. Later, radio-bright blazars were shown to be associated with IceCube neutrino events with high statistical significance. These associations remained unconfirmed with the data of independent experiments. Here, we report on the detection of a rare neutrino event with the estimated energy of 224 ± 75 TeV from the direction of TXS 0506 + 056 by the new Baikal Gigaton Volume Detector (Baikal-GVD) in April 2021. This event is the highest energy cascade detected so far by the Baikal-GVD neutrino telescope from a direction below horizon. The result supports previous suggestions that radio blazars in general, and TXS 0506 + 056 in particular, are the sources of high-energy neutrinos, and opens up the cascade channel for the neutrino astronomy.
A corrected energy dependence of the depth of the maximum in the wide range of energies 10
15
to 10
18
eV is obtained using data collected at the Tunka-133 facility over 7 years of operation ...(2009–2017) and the TAIGA-HiSCORE facility in the 2019–2020 season. At the highest energies, our results match those of the Pierre Auger observatory. The results are converted to parameter ❬ln
A
❭, which characterizes the mean EAS composition.
Scintillation detectors for the TAIGA experiment Astapov, I.; Bezyazeekov, P.; Borodin, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
It is planned that new TAIGA-Muon detectors will complement the existing Tunka-GRANDE facility of scintillation detectors of the TAIGA gamma-observatory in the Tunka valley, Russia. The new design of ...scintillation detector with wavelength shifting bars and PMTs is developed. The first prototype of the counter was installed and tested using infrastructure of the Tunka-GRANDE installation in 2017. The mass production of counters has begun in 2018 at the Novosibirsk State University.
