73 research outputs found
On the Velocity of Light Signals in the Deep Underwater Neutrino Experiments
During the last few years deep underwater neutrino telescopes of a new
generation with dimensions close to 100 m or more were taken into operation.
For the correct track reconstruction and for the interpretation of light pulses
from calibration lasers one has to use the group velocity for light signals.
The difference between group velocity leads to an additional delay of about 10
ns for a distance of 100 m between light source and photjmultiplier. From the
time of the appearance of the first projects of deep underwater neutrino
telescopes in the middle of 70th this fact was never mentioned in the
literature.Comment: 4 pages, 2 figure
Characterization of Ti-B-C-N Nanocomposite Coatings
Nanocomposite Ti-B-N-C coatings were deposited by magnetron sputtering of TiN and B4C targets in the argon-nitrogen atmosphere at different nitrogen flow rates (FN2). The structure, chemical bonding and mechanical properties were investigated. The results of the investigations of the nanocomposite, TiN and BCN coatings show that the Ti-B-C-N coatings consist of the TiNC nanocrystals (3.4 – 6.5 nm) embedded into the amorphous matrix that consists of amorphous boron nitrogen (a-BN) and amorphous carbon (a-C). The coatings contain a small admixture of titanium oxides that are aggregated at the grain boundaries. The coatings deposited at high nitrogen flow rates were textured. An introduction of nitrogen prompts the formation of the nanocrystallites of the TiN-TiC solid solutions and the a-BN amorphous tissue, which, in turn, causes the improvement of the mechanical properties of the Ti-B-C-N coatings. The best samples ex-hibited nanohardnes above 39 GPa.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3505
Latest results of the Tunka Radio Extension (ISVHECRI2016)
The Tunka Radio Extension (Tunka-Rex) is an antenna array consisting of 63
antennas at the location of the TAIGA facility (Tunka Advanced Instrument for
cosmic ray physics and Gamma Astronomy) in Eastern Siberia, nearby Lake Baikal.
Tunka-Rex is triggered by the air-Cherenkov array Tunka-133 during clear and
moonless winter nights and by the scintillator array Tunka-Grande during the
remaining time. Tunka-Rex measures the radio emission from the same air-showers
as Tunka-133 and Tunka-Grande, but with a higher threshold of about 100 PeV.
During the first stages of its operation, Tunka-Rex has proven, that sparse
radio arrays can measure air-showers with an energy resolution of better than
15\% and the depth of the shower maximum with a resolution of better than 40
g/cm\textsuperscript{2}. To improve and interpret our measurements as well as
to study systematic uncertainties due to interaction models, we perform radio
simulations with CORSIKA and CoREAS. In this overview we present the setup of
Tunka-Rex, discuss the achieved results and the prospects of mass-composition
studies with radio arrays.Comment: proceedings of ISVHECRI2016 conferenc
Status of the Lake Baikal Experiment
We review the present status of the Baikal Underwater Neutrino Experiment and
report on neutrino events recorded with the detector stages NT-36 and NT-96.Comment: 5 pages, 4 PostScript figures, uses here.sty and mine.sty, submitted
to the Proc. of 5th Int. Workshop on Topics in Astroparticle and Underground
Physics (LNGS INFN, Assergi, September 7-11, 1997
The amplitude calibration of the TUNKA radio extension (Tunka-Rex)
Tunka-Rex is an experiment for the radio detection of cosmic-ray air showers in Siberia. It consists of 25 radio antennas, distributed over an area of 1 km2. It is co-located with Tunka-133, an air-Cherenkov detector for cosmic-ray air showers. Triggered by Tunka-133, Tunka-Rex records the radio signal, emitted by air showers with energies above 1017 eV. Its goal is to probe the capabilities of a radio detector, especially for the determination of the energy and elemental composition of cosmic ray primaries. To compare the measurements of Tunka-Rex to other radio detectors or to models describing the radio emission, the radio signal in each station has to be reconstructed in terms of physical units. Therefore, all hardware components have to be calibrated. We show how the calibration is performed and compare it to simulations
Registration of atmospheric neutrinos with the Baikal neutrino telescope
We present first neutrino induced events observed with a deep underwater
neutrino telescope. Data from 70 days effective life time of the BAIKAL
prototype telescope NT-96 have been analyzed with two different methods. With
the standard track reconstruction method, 9 clear upward muon candidates have
been identified, in good agreement with 8.7 events expected from Monte Carlo
calculations for atmospheric neutrinos. The second analysis is tailored to
muons coming from close to the opposite zenith. It yields 4 events, compared to
3.5 from Monte Carlo expectations. From this we derive a 90 % upper flux limit
of 1.1 * 10^-13 cm^-2 sec^-1 for muons in excess of those expected from
atmospheric neutrinos with zenith angle > 150 degrees and energy > 10GeV.Comment: 20 pages, 11 figure
The Lake Baikal neutrino experiment
We rewiew the present status of the Baikal Neutrino Project and present the
results of a search for high energy neutrinos with the detector intermediate
stage NT-96.Comment: 3 pages, 2 figures, to appear in the Proceedings of Sixth
International Workshop on Topics in Astroparticle and Underground Physics
(TAUP99), September 6-10, 1999, Pais, Franc
First analysis of inclined air showers detected by Tunka-Rex
The Tunka Radio Extension (Tunka-Rex) is a digital antenna array for the detection of radio emission from cosmic-ray air showers in the frequency band of 30 to 80 MHz and for primary energies above 100 PeV. The standard analysis of Tunka-Rex includes events with zenith angle of up to 50?. This cut is determined by the efficiency of the external trigger. However, due to the air-shower footprint increasing with zenith angle and due to the more efficient generation of radio emission (the magnetic field in the Tunka valley is almost vertical), there are a number of ultra-high-energy inclined events detected by Tunka-Rex. In this work we present a first analysis of a subset of inclined events detected by Tunka-Rex. We estimate the energies of the selected events and test the efficiency of Tunka-Rex antennas for detection of inclined air showers
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