NEVOD-DECOR experiment: results and future Saavedra, O; Amelchakov, M B; Barbashina, N S ...
Journal of physics. Conference series,
01/2013, Letnik:
409, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Russian-Italian NEVOD-DECOR experiment on the measurements of the local muon density spectra (LMDS) at various zenith angles gave possibility to obtain information on primary cosmic ray flux and ...interaction characteristics in a record wide energy range from 1015 to more than 1018 eV. Comparison of the measurement results with CORSIKA-based simulations showed the increase of LMDS slope at PeV energies of primaries (corresponding to the first knee); a trend to a heavier primary mass composition above the knee; indication for a second knee (a further increase of the spectrum slope near 1017 eV). At large zenith angles and high muon densities (corresponding to primary energies around 1018 eV) a considerable excess of muon bundle events in comparison with the expectation based on independent estimates of the primary spectrum and widely used hadron interaction models has been found. In 2011, a new phase of measurements of the energy spectrum of cascade showers initiated by high-energy muons in water and of the energy deposit of muon bundles at various zenith angles and muon multiplicities started. Further plans include the deployment of a traditional EAS array around the NEVOD-DECOR complex.
First results of investigations of the energy deposits of inclined muon bundles in the ground-based Cherenkov water detector NEVOD are presented. As a measure of the muon bundle energy deposit, the ...total number of photoelectrons detected by PMTs of the Cherenkov calorimeter is used. For each event, the local muon density at the observation point and the muon bundle arrival direction are estimated from the data of the coordinate-tracking detector DECOR. Registration of the bundles in a wide range of zenith angles allows to explore the interval of primary particle energies from ∼ 1016 to ∼ 1018 eV. Measurement results are compared with CORSIKA based simulations of EAS muon component. It is found that the mean energy of muons detected in the bundles rapidly increases with the zenith angle and reaches about 500 GeV near the horizon.
The analysis of spatial distribution of Cherenkov light generated by cascade showers in Cherenkov water detector (CWD) NEVOD was performed. Showers generated by nearly horizontal muons were selected. ...Muons tracks were reconstructed with high precision using the coordinate tracking detector DECOR. For the first time, the dependence of Cherenkov light intensity on the depth of a shower at different distances from its axis was measured.
Quasispherical Module (QSM) of Cherenkov water detector NEVOD represents six low-noise FEU-200 photomultipliers with flat photocathodes (15 cm in diameter), oriented along the axes of orthogonal ...coordinate system. Such configuration allows to register Cherenkov radiation arriving from any direction with almost equal efficiency. The results of measurements of QSM characteristics in the sensitive volume of the NEVOD detector during the registration of Cherenkov radiation of single muons at different distances and angles are discussed.
To solve the problem of the excess of multi-muon events observed in several cosmic ray experiments at ultra-high energies (so-called “muon puzzle”), an analysis of the energy characteristics of the ...muon component of extensive air showers (EAS) is required. A possible approach to such investigations is the measurement of the energy deposit of muon bundles in the detector, which provides information on the mean muon energy. In the experiment now being conducted at the NEVOD-DECOR complex, the local muon density and EAS arrival direction are determined according to the data of the coordinate-tracking detector DECOR, whereas the energy deposit is measured by means of the Cherenkov water calorimeter NEVOD. Results of the measurements of the energy deposit of inclined muon bundles based on the data accumulated during more than 23,200 h observations in 2012 – 2016 are presented and compared with simulations performed by means of the CORSIKA code.
The Russian-Italian NEVOD-DECOR experiment on measurements of the local muon density spectra at various zenith angles gave the possibility to obtain important information on the primary cosmic ray ...flux and interaction characteristics in a wide energy range from 1015 to more than 1018 eV. At large zenith angles and high muon densities, a considerable excess of muon bundles has been found in comparison with expectation. In this paper, an update of these investigations is presented and some new results obtained by the collaboration are discussed.
Investigations of the energy characteristics of muon component with the increase of the primary cosmic rays energy can be a key to solving 'muon puzzle' - the problem of excess of EAS muons (observed ...in several experiments at high - ALEPH, DELPHI - and ultrahigh energies - DECOR, Pierre Auger Observatory) in comparison with the expected flux. The measurements results of the energy deposit of inclined muon bundles in water depending on the zenith angle and the local density of muons are presented. As a measure of the energy deposit, the total number of photoelectrons registered by PMTs of the Cherenkov water calorimeter NEVOD was used. The local density of muons, which gives an estimate of the energy of primary particles was obtained from the data of coordinate-tracking detector DECOR. The experimental data are compared with the results of calculations based on simulations of the muon component of EAS by means of the CORSIKA code.
A technique for the reconstruction of cascade profiles by means of Cherenkov radiation in the water of the NEVOD detector is discussed. NEVOD is equipped with a dense spatial lattice of optical ...modules. The analyzed cascades have been generated either along near-horizontal muons (zenith angles between 85 and 90°), which's tracks are reconstructed by means of the tracking detector DECOR, or by muons with unknown tracks over a wider zenith angle range of 50-90°. Mean cascade profiles and energy spectra of cascades measured during the experimental series of about 7950 hours of 'live time' are presented.
In several cosmic ray experiments, an excess of multi-muon events in comparison with calculations performed in frame of the widely used hadron interaction models was found. In order to solve this ...puzzle, investigations of muon energy characteristics in EAS are required. An experiment on the measurement of the energy deposit of muon bundles in water has been started with the NEVOD-DECOR experimental complex. The results of the analysis of the first experimental data are discussed. It has been found that the average specific energy deposit in the Cherenkov calorimeter appreciably increases with zenith angle, thus reflecting the increase of the mean muon energy in the bundles. A possible evidence for an increase of the energy deposit at primary energies above 1017 eV is observed.
Proposal of NEVOD-EAS shower array Shulzhenko, I A; Amelchakov, M B; Barbashina, N S ...
Journal of physics. Conference series,
01/2013, Letnik:
409, Številka:
1
Journal Article
Recenzirano
Odprti dostop
New setup for detection of EAS electromagnetic component at the knee region of primary energies is under construction on the basis of the experimental complex NEVOD (Moscow, Russia). The measuring ...system of the EAS array has a cluster organization. Clusters are located on the roofs of laboratory buildings of MEPhI (Moscow). Features of measuring and DAQ systems, results of investigations of characteristics of a single counter and the event formation algorithm from the data of separate clusters are discussed.
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