Cherenkov Light Array Research Articles

The primary cosmic-ray energy spectrum measured with the Tunka-133 array

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.

Cherenkov EAS arrays in the Tunka astrophysical center: From Tunka-133 to the TAIGA gamma and cosmic ray hybrid detector

Abstract One of the most informative methods of cosmic ray studies is the detection of Cherenkov light from extensive air showers (EAS). The primary energy reconstruction is possible by using the Earth’s atmosphere as a huge calorimeter . The EAS Cherenkov light array Tunka-133, with ∼ 3 km 2 geometrical area, is taking data since 2009. Tunka-133 is located in the Tunka Astrophysical Center at ∼ 50 km west of Lake Baikal. This array allows us to perform a detailed study of the energy spectrum and the mass composition in the energy range from 6 ⋅ 1 0 15 eV to 1 0 18 eV . Most of the ongoing efforts are focused on the construction of the first stage of the detector TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy). The latter is designed for the study of gamma rays and charged cosmic rays in the energy range of 1 0 13 eV – 1 0 18 eV . The TAIGA prototype will consist of ∼ 100 wide angle timing Cherenkov stations (TAIGA-HiSCORE) and three IACTs deployed over an area of ∼ 1 km 2 . The installation of the array is planned to be finished in 2019 while the data-taking can start already during the commissioning phase. The joint reconstruction of energy, direction, and core position of the imaging and non-imaging detectors will allow us to increase the distance between the IACTs up to 800 m, therefore providing a low-cost, highly sensitive detector. The relatively low cost together with the high sensitivity for energies ≥ 30–50 TeV make this pioneering technique very attractive for exploring galactic PeVatrons and cosmic rays. In addition to the Cherenkov light detectors we intend to deploy surface and underground muon detectors over an area of 1 km 2 with a total area of about 1000 m 2 . The results of the first season of coincident operation of the first ∼ 4 m diameter IACT with an aperture of ∼ 10°with 30 stations of TAIGA-HiSCORE will be presented.

Cosmic Ray Energy Spectrum derived from the Data of EAS Cherenkov Light Arrays in the Tunka Valley

The extensive air shower Cherenkov light array Tunka-133 collected data during 7 winter seasons from 2009 to 2017. From 2175 hours of data taking, we derived the differential energy spectrum of cosmic rays in the energy range 6 · 1015 2 · 1018 eV. The TAIGA-HiSCORE array is in the process of continuous expansion and modernization. Here we present the results obtained with 28 stations of the first HiSCORE stage from 35 clear moonless nights in the winter of 2017-2018. The combined spectrum of two arrays covers a range of 2 · 1014 – 2 · 1018 eV.

Results from Tunka-133 (5 years observation) and from the Tunka-HiSCORE prototype

Data obtained with two detectors located at the Tunka Cosmic Ray facility are presented. The Cherenkov light array for registration of extensive air showers (EAS) Tunka-133 collected data during 5 winter seasons since 2009 to 2014. The differential energy spectrum of all particles and the dependence of the average maximum depth on the energy in the range of 6 · 1015−1018 eV measured for 1540 hours of observation are presented.

Energy spectrum and mass composition of cosmic rays, by the data of the Tunka-133 array

The Tunka-133 Cherenkov light array for the detection of extensive air showers (EAS) acquires data over the five winters from 2009 to 2014. The direction of arrival, the shower core coordinates on the plane of observation, the primary energy, and the depth of the shower maximum are reconstructed for each EAS. A differential all-particle energy spectrum is obtained in the energy range of 6 × 1015–3 × 1018 eV over 1540 h, along with the energy dependence of the average depth of the shower maximum in the range of 6 × 1016–3 × 1018 eV. Based on this dependence, the variation in the average composition of the primary cosmic rays is estimated as a function of energy.

Primary CR energy spectrum and mass composition by the data of Tunka-133 array

The Cherenkov light array for the registration of extensive air showers (EAS) Tunka-133 collected data during 5 winter seasons from 2009 to 2014. The differential energy spectrum of all particles and the dependence of the average maximum depth on the energy in the range of 6 · 10 15 -10 18 eV measured for 1540 hours of observation are presented.

Tunka-133: Results of 3 year operation

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 Tunka-133 EAS Cherenkov light array: Status of 2011

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 Cosmic Ray Mass Composition in the Energy Range [formula omitted] measured with the Tunka Array: Results and Perspectives

The final analysis of the Extensive Air Shower (EAS) maximum ( X m a x ) depth distribution derived from the data of Tunka-25 atmospheric Cherenkov light array in the energy range 3 ⋅ 10 15 – 3 ⋅ 10 16 eV is presented. The perspectives of X m a x studies with the new Cherenkov light array Tunka-133 of 1 km 2 area, extending the measurements up to 10 18 eV, are discussed.

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.

The shapes of the atmospheric Cherenkov light images from extensive air showers

Experimental results on the shapes of atmospheric Cherenkov light images from Extensive Air Showers at E0 = 1013–1014 eV are presented. The results are based on data obtained by the first element of the Cherenkov light array of the EAS-TOP experiment at Campo Imperatore (2005 m a.s.l., National Gran Sasso Laboratories, Italy). Images are obtained with pixel field of view ω = 1.5 × 10−5 sr and full field of view Ω ≈ 10−3 sr. The shapes of the images agree with the expectations and their fluctuations are large and significant. Experimental data on the dependence of the image shapes on the detection geometry are reported. The images are well reproduced by two independent side by side detectors, within measured accuracies. Such accuracies (≈ 15% for large photoelectron content) define the level at which each pixel content is related to the shower structure. The presence of events characterized by patterns with multiple structures is proved. It is shown that such features are related to physical fluctuations of the shower structure.