497 research outputs found
Primary gamma ray selection in a hybrid timing/imaging Cherenkov array
This work is a methodical study on hybrid reconstruction techniques for
hybrid imaging/timing Cherenkov observations. This type of hybrid array is to
be realized at the gamma-observatory TAIGA intended for very high energy
gamma-ray astronomy (>30 TeV). It aims at combining the cost-effective
timing-array technique with imaging telescopes. Hybrid operation of both of
these techniques can lead to a relatively cheap way of development of a large
area array. The joint approach of gamma event selection was investigated on
both types of simulated data: the image parameters from the telescopes, and the
shower parameters reconstructed from the timing array. The optimal set of
imaging parameters and shower parameters to be combined is revealed. The cosmic
ray background suppression factor depending on distance and energy is
calculated. The optimal selection technique leads to cosmic ray background
suppression of about 2 orders of magnitude on distances up to 450 m for
energies greater than 50 TeV.Comment: 4 pages, 5 figures; proceedings of the 19th International Symposium
on Very High Energy Cosmic Ray Interactions (ISVHECRI 2016
Measurement of Cosmic Ray Primary Energy with the Atmospheric Cherenkov Light Technique in Extensive Air Showers
The advantage and problems of the primary energy measurement using the Cherenkov light from extensive air showers are discussed. The problem of absolute energy calibration has been solved during the analysis of the data of complex QUEST experiment at the EAS-TOP array. The results of QUEST experiment has been used for the analysis of the data of pure Cherenkov light array Tunka
Results of investigation of muon fluxes of superhigh energy cosmic rays with X-ray emulsion chambers
The overall data from the investigation of the cosmic ray muon flux in the range of zenith angles (0-90) deg within the energy range (3.5 to 5.0) TeV is presented. The exposure of large X-ray emulsion chambers underground was 1200 tons. year. The data were processe using the method which was applied in the experiment Pamir and differred from the earlier applied one. The obtained value of a slope power index of the differential energy spectrum of the global muon flux is =3.7 that corresponds to the slope of the pion generation differential spectrum, gamma sub PI = 2.75 + or - .04. The analysis of the muon zenith-angular distribution showed that the contribution of rapid generation muons in the total muon flux agree the best with the value .2% and less with .7% at a 90% reliability level
Lower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap
Using two experimental techniques, we studied single crystals of the 122-FeAs
family with almost the same critical temperature, Tc. We investigated the
temperature dependence of the lower critical field of a single crystal under
static magnetic fields parallel to the axis. The temperature dependence of the
London penetration depth can be described equally well either by a single
anisotropic -wave-like gap or by a two-gap model, while a d-wave approach
cannot be used to fit the London penetration depth data. Intrinsic multiple
Andreev reflection effect spectroscopy was used to detect bulk gap values in
single crystals of the intimate compound, with the same Tc. We estimated the
range of the large gap value 6-8 meV (depending on small variation of and its a
space anisotropy of about 30%, and the small gap 1.7 meV. This clearly
indicates that the gap structure of our investigated systems more likely
corresponds to a nodeless s-wave two gaps.Comment: 9 pages, 6 figure
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