EAS Cherenkov Research Articles

60th Anniversary of the Development of the First Installation on the Search for Cosmic Particle Sources in a Given Direction by EAS Cherenkov Radiation at the Lebedev Physical Institute

60th Anniversary of the Development of the First Installation on the Search for Cosmic Particle Sources in a Given Direction by EAS Cherenkov Radiation at the Lebedev Physical Institute

Depth of the Maximum of Extensive Air Showers (EASes) and the Mean Mass Composition of Primary Cosmic Rays in the 1015–1018 eV Range of Energies, According to Data from the TUNKA-133 and TAIGA-HiSCORE Arrays for Detecting EAS Cherenkov Light in the Tunkinsk Valley

Depth of the Maximum of Extensive Air Showers (EASes) and the Mean Mass Composition of Primary Cosmic Rays in the 1015–1018 eV Range of Energies, According to Data from the TUNKA-133 and TAIGA-HiSCORE Arrays for Detecting EAS Cherenkov Light in the Tunkinsk Valley

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.

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.

Application of New Approximations of the Lateral Distribution of EAS Cherenkov Light in the Atmosphere

A new knee-like approximation of the lateral distribution function (LDF) of EAS Cherenkov light in the 30–3000 TeV energy range was proposed and tested with simulated showers in our earlier studies. This approximation fits the LDFs of individual showers accurately for all types of primary particles gamma-rays, protons, and nuclei) and is suitable for reconstructing the shower core, determining the energy, and separating gamma-induced showers from hadron-induced ones. In the present study, the knee-like fitting function is used to determine the parameters of real showers detected by TAIGA-HiSCORE. It is demonstrated that this approximation characterizes properly all types of individual LDFs of experimental events in the 300–1000 TeV range. The accuracy of fit is governed by fluctuations intrinsic to the process of measurement of the Cherenkov photon density. The probability density function of these fluctuations was reconstructed and introduced into simulations. Certain useful methodical applications of the knee-like approximation are con-sidered, and the possibility of shower sorting into nuclei groups is examined. The extensive statistical coverage and detailed LDF measurement data of HiSCORE have provided the first opportunity to examine in depth the LDF of Cherenkov radiation in the 300–1000 TeV range.

Radio emissions of extensive air showers with energies higher than 5 × 1018 eV at a frequency of 32 MHz according to measurements at the Yakutsk array

Results obtained from the measuring the radio emissions from extensive air shower particles with energies higher than 5 × 1018 eV at a frequency of 32 MHz are presented. A generalized formula is derived to describe the spatial distribution of radio emissions using the main EAS characteristics: energy Е 0 and depth of maximum development of shower Х max. The approximating function describes the data at average and large distances from a shower axis. The ratio of signal amplitudes at distances of 175 m and 725 m is used to determine Х max for an average shower with an energy of 1.54 × 1019 eV, which in our case is equal to Х max = 769 ± 34 g cm−2. Within the experimental error, the result for Х max is consistent with data obtained using EAS Cherenkov light.

Response time structure of electrons and muons recorded by scintillation detectors in showers with energies higher than 5 × 1018 eV at the Yakutsk EAS array: The search for neutrinos

The procedure for and results from a search for showers generated by such neutral particles as high energy gamma rays and astroneutrinos are presented. A comprehensive analysis of data on electrons, muons, and EAS Cherenkov light, and their response time in scintillation and Cherenkov detectors, is performed.

Study of Cherenkov light lateral distribution function around the knee region in extensive air showers

The Cherenkov light lateral distribution function (LDF) was simulated with the CORSIKAcode in the energy range (1013 - 1016) eV. This simulation was performed for conditions and configurations of the Tunka EAS Cherenkov array for the two primary particles (p and Fe). Basing on the simulated results, many approximated functions are structured for two primary particles and different zenith angles. This allowed us to reconstruct the EAS events, which is, to determine the type and energy of the primary particles that produced showers from signal amplitudes of Cherenkov radiation measured by the Tunka Cherenkov array experiment. Comparison of the calculated LDF of Cherenkov radiation with that measured at the Tunka EAS array shows the ability to identify the primary particle that initiated the EAS cascades by determining its primary energy around the knee region of the cosmic ray spectrum.

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 – Multi-component EAS detector for high energy cosmic ray studies

The EAS Cherenkov array Tunka-133, with about 3km2 sensitive area, has been installed in the Tunka Valley, Siberia. The accessible energy range is 1015–1018eV. In this contribution, a description of the array and main results obtained so far are presented. A current update of the array includes the deployment of scintillation stations, radio antennas, as well as optical stations. The deployments of these optical stations are the first step towards Tunka-HiSCORE, a wide-angle, large field-of-view gamma-ray telescope.

Design of a Cherenkov telescope for the measurement of PCR composition above 1 PeV

The problem of PCR Composition at super high energies is far from being solved. EAS Cherenkov light spatial-angular distribution (CL SAD) can yield important information on the primary mass. In order to use EAS CL SAD for the study of PCR composition one needs a set of imaging telescopes with the appropriate parameters. On the basis of full Monte-Carlo simulations the main features of such telescopes are analyzed for a specific observation level 4km which is typical for the Eastern Pamir mountains.

Design of a Cherenkov telescope for the measurement of PCR composition above 1 PeV

The problem of PCR Composition at super high energies is far from being solved.EAS Cherenkov light spatial-angular distribution (CL SAD) can yield important information on the primary mass. In order to use EAS CL SAD for the study of PCR composition one needs a set of imaging telescopes with the appropriate parameters supported by a dense net of fast optical detectors capable of measuring EAS Cherenkov light pulses. On the basis of full Monte-Carlo simulations the pixel size of imaging telescopes is optimized for a specific observation level ∼4km which is typical for the Eastern Pamir mountains.Another goal to be pursued by the new detector array is the search for ultra high energy gamma ray sources and this is where the imaging technique can help a lot. A simple criterion is introduced to recognize gamma-quanta against the proton background and its performance, once again analyzed using simulated events, sets certain limits to the pixel size.

Reminiscences of cosmic ray research in Mexico

Cosmic ray research in Mexico dates from the early 1930s with the work of the pioneering physicist, Manuel Sandoval Vallarta and his students from Mexico. Several experiments of international significance were carried out during that period in Mexico: they dealt with the geomagnetic latitude effect, the north–south and west–east asymmetry of cosmic ray intensity, and the sign of the charge of cosmic rays. The international cosmic ray community has met twice in Mexico for the International Cosmic Ray Conferences (ICRC): the fourth was held in Guanajuato in 1955, and the 30th took place in Mérida, in 2007. In addition, an international meeting on the Pierre Auger Collaboration was held in Morelia in 1999, and the International Workshop on Observing UHE Cosmic Rays took place in Metepec in 2000. A wide range of research topics has been developed, from low-energy Solar Energetic Particles (SEP) to the UHE. Instrumentation has evolved since the early 1950s, from a Simpson type neutron monitor installed in Mexico City (2300 m asl) to a solar neutron telescope and an EAS Cherenkov array, (within the framework of the Auger International Collaboration), both at present operating on Mt. Sierra La Negra in the state of Puebla (4580 m asl). Research collaboration has been undertaken with many countries; in particular, the long-term collaboration with Russian scientists has been very fruitful.

THE TUNKA EXPERIMENT: TOWARDS A 1-KM2 CHERENKOV EAS ARRAY IN THE TUNKA VALLEY

The project of an EAS Cherenkov array in the Tunka Valley/Siberia with an area of about 1 km2 is presented. The new array will have a ten times bigger area than the existing TUNKA-25 array and will permit a detailed study of the cosmic ray energy spectrum and the mass composition in the energy range from 1015 to 1018 eV.

About a possibility of the analysis of the mass composition of cosmic rays on the basis of the space-temporal distribution of the EAS Cherenkov light

The space-temporal distribution of the EAS Cherenkov light initiated by p, α and nuclei of M H VH groups in energy region 1 ÷ 20 TeV per nucleus is investigated using the Monte-Carlo method. Essential differences are found in the shape of the front and fluctuations of the Cherenkov light from air showers created by different primary nuclei. These differences can be successfully applied for the separation of showers. Particularly, for selection criteria directed at the separation of showers of M group we have the suppression factor of protons ~ 50. For VH group a practically complete suppression of protons is possible.

The study of primary cosmic rays energy spectrum and mass composition in the energy range 0.5 – 50 PeV with TUNKA Eas Cherenkov array

The Tunka-13 EAS array has operated two winter seasons since 1996 until 1998 years. It consists of 13 Cherenkov light detectors based upon the QUASAR-370 phototubes. The array covers the area 240 x240 m2 and measures the primary energy, derived from Cherenkov light flux, and individual lateral distribution functions (LDF). Good energy and angular resolution of the array permits to study the irregularities in energy spectrum following the classic “knee”.

EAS Cherenkov at Gran Sasso: correlated observations at the surface and with deep underground events

We present the first results of the observations of the atmospheric Cherenkov light emission from Extensive Air Showers, obtained from the EAS-TOP experiment at Campo Imperatore (at the Gran Sasso Laboratory). Data concern measurements at low energies, and the correlations with the e.m. and GeV muon detectors at the surface, and with the events observed deep underground (LVD detector).

Imaging of atmospheric EAS Cherenkov light at EAS-TOP

Images of atmospheric EAS Cherenkov light have been recorded in connection with the EAS-TOP experiment. We describe the technique (based on a multianode photomultiplier Philips XP4702) and present some preliminary data analysis.