N. S. Barbashina

• Doctor of Philosophy
• Researcher at National Research Nuclear University MEPhI (Moscow Engineering Physics Institute)

The data of cosmic ray NEVOD-DECOR experiment on the investigation of inclined muon bundles for a long time period (May 2012 - March 2021) are presented. The analysis showed that the observed intensity of muon bundles at primary cosmic ray energies of about 1 EeV and higher can be compatible with the expectation in frame of widely used hadron inter...

Results of measurements of the energy characteristics of muon bundles in inclined extensive air showers in the NEVOD-DECOR experiment are presented. Estimates of the average energy of muons in the bundles in the energy range of primary particles from 10 to 1000 PeV were obtained and compared with the calculated expected values for various assumptio...

The data of cosmic ray NEVOD-DECOR experiment on the investigation of inclined muon bundles for a long time period (May 2012 - March 2021) are presented. The analysis showed that the observed intensity of muon bundles at primary cosmic ray energies of about 1 EeV and higher can be compatible with the expectation in frame of widely used hadron inter...

MegaScience projects are unique scientific experiments and facilities of a large scale that were initiated to allow to go beyond modern knowledge in the field of fundamental sciences and open up new opportunities in the technological development. The implementation of such complex projects requires the combined efforts of many scientists and instit...

The Experimental complex NEVOD includes several different setups for studying various components of extensive air showers (EAS) in the energy range from 10¹⁰ to 1018eV. The NEVOD-EAS array for detection of the EAS electron-photon component began its data taking in 2018. It is a distributed system of scintillation detectors installed over an area of...

Results from an analysis of URAGAN muon hodoscope data are used to identify effects observed in connection with thunderstorms recorded above and at considerable distances from the setup. These include quasiperiodic disturbances of the muon flux characteristics, reductions in the count rate, and changes in the muon flux anisotropy. An algorithm is c...

The Experimental complex NEVOD includes several different setups for studying various components of extensive air showers (EAS) in the energy range from 10^10 to 10^18 eV. The NEVOD-EAS array for detection of the EAS electron-photon component began its data taking in 2018. It is a distributed system of scintillation detectors installed over an area...

Forbush effects caused by powerful X-class solar flares are studied using URAGAN muon hodo-scope data for the period 2007–2019. The URAGAN muon hodoscope registers the cosmic ray muon fluxon the Earth’s surface from different directions simultaneously. This allows study of the energy, angular, andspace–time characteristics of variations in the cosm...

The experimental data on thermal neutron flux registered by the “Neutron” setup (MEPhI, Moscow) on the Earth's surface for the period from May 2015 to February 2019 were analyzed. The effects of Forbush decrease (FD) and the lunar cycles were studied. The comparison with the results of FD studies in data of two other setups: the Moscow neutron moni...

Coronal holes generate a high speed solar wind. This wind is the cause of magnetic storms on the Earth during the years of low solar activity. Also a high speed solar wind creates disturbances in the interplanetary magnetic field. The disturbance may reflect cosmic rays hitting them in the direction of the Earth. As a result, it is possible to obse...

Data of NEVOD-DECOR experiment on investigations of inclined cosmic ray muon bundles for a long time period (May 2012 – May 2020) are presented. Their comparison with the results of calculations based on simulations of extensive air shower hadron and muon components is carried out. The analysis showed that the observed intensity of muon bundles at...

In comparison with calculations, the excess of multimuon events found in many experiments at ultrahigh energies of extensive air showers (EASs) cannot be explained using modern models of hadron interactions. The existence of muon excess is called the muon puzzle. One of the ways to solve this problem is to study the energy characteristics of the EA...

Modern nuclear physics is impossible without the implementation of projects of the megascience class, for the creation of which the efforts of many organizations and countries are consolidated. The level and complexity of experiments carried out with the use of such facilities is provided by scientific researchers with a wide range of competencies....

Fundamental research in the field of high energy physics and nuclear physics is carried out at large international experiments with the joint participation of scientific organizations and research universities. This article discusses the features of the participation of a nuclear university in international research projects of the Mega-science cla...

Coronal mass ejections (CME) have an impact on the flux of cosmic rays that penetrate the disturbed areas in the heliosphere and the near-terrestrial space. Unlike most ground-based cosmic ray detectors, the URAGAN muon hodoscope (MEPhI) allows to investigate both the integrated counting rate of registered particles and angular characteristics of t...

Coronal mass ejections are among the most powerful disturbances of the interplanetary space. They can influence the state of the near-Earth space, including magnetosphere of the Earth. In addition, such disturbances modulate the flux of cosmic rays and penetrate both the heliosphere and the Earth’s magnetosphere. In order to find an early alert of...

Results of the study of variations of cosmic ray muon flux at the Earth surface during Forbush decreases registered in 2007–2018 by means of the muon hodoscope URAGAN are presented. The dynamics of the amplitude spectral index at different stages (the decrease, the minimum, and the recovery), which correspond to different phases of the influence of...

Investigations of the energy loss of muon bundles are being conducted at the Experimental complex NEVOD. Such investigations are directed to detailed study of “muon puzzle” (the excess of multi-muon events observed in several cosmic ray experiments at ultra-high energies). Results of measurements of the muon bundle energy deposit during a long peri...

The influence of a high-speed solar wind on the state of magnetosphere, as well as on the cosmic ray flux registered on the Earth’s surface by the muon hodoscope URAGAN (MEPhI) is discussed. The results of the analysis of the parameters of muon flux local anisotropy in the periods of low solar activity (2008–2009 and 2017–2018) during geomagnetic d...

Results are presented from analyzing experimental data on 0.1–10 TeV cascade showers generated by muons in the NEVOD Cherenkov water detector. The procedure for selecting and reconstructing the parameters of events with cascades in the detector volume is discussed. Results are presented from measurements of the zenith angle distribution of cascades...

Energy characteristics of the muon component of extensive air showers (EASes) are investigated at the NEVOD experimental complex in order to solve the problem of a detected excess of muons in EASes at ultrahigh energies, relative to simulation results. The dependences of the energy deposit of muon bundles on the zenith angle and the local muon dens...

The NEVOD experimental complex was created at MEPhI. It includes several facilities for studying the electron–photon, muon, and hadron components of the EAS in the energy range of 1 PeV to 1 EeV. This work presents the first results for two months of the joint operation of five facilities (NEVOD-EAS, CWD, CTS, PRISMA-32, and DECOR). The problems of...

At the beginning of September 2017, the Sun was characterized by anomalously high solar activity (SA), which was unusual for the region of the minimum of the 11-year cycle. A great many powerful flares of the M- and X-classes were observed; these were accompanied by powerful coronal mass ejections (CMEs). These events caused strong magnetic storms...

Results are presented from an analysis of changes in the muon flux of cosmic rays during Forbush effects, recorded by the URAGAN muon hodoscope in the period 2012–2017 and the scintillation muon hodoscope in 2016–2017. Characteristics of the Forbush effects for this period are analyzed. The obtained characteristics of muon flux variations are compa...

A way of detecting local anisotropies of the muon flux using the matrix-form data of the URAGAN hodoscope (MEPhI) is proposed. Confidence intervals for estimating the matrix-data mathematical expectations in observations with reference and sliding data-sampling periods are selected, indicator functions are constructed, and a procedure for space–tim...

A way of eliminating diurnal variations in muon fluxes for matrix observations of the URAGAN hodoscope (MEPhI) is proposed, based on a matrix digital two-dimensional low-pass filter. Its structure is developed on the basis of matrix elementwise multiplications. Diurnal variations in the muon fluxes for the sequence of matrix observations of the Ura...

Continuous monitoring of the muon flux over wide ranges of zenith and azimuth angles with the URAGAN detector (Moscow, 55.7° N, 37.7° E, 173 m AMSL) allows detection of variations in its intensity and angular distribution. A way of locating domains of anisotropy in the muon angular distribution is described, and they are mapped in matrix form in th...

The flux of cosmic rays passing through the heliosphere changes its characteristics (energy and angular distribution) due to the influence of the interplanetary magnetic field. Because of this, the muon flux produced by primary cosmic rays in the Earth atmosphere also changes its characteristics. Muons registered at the surface of the Earth are gen...

An experiment on the measurements of the energy deposit of inclined cosmic ray muon bundles is being conducted at the experimental complex NEVOD (MEPhI). The complex includes the Cherenkov water calorimeter with a volume of 2000 m3 and the coordinate-tracking detector DECOR with a total area of 70 m2. The DECOR data are used to determine the local...

Coronal mass ejections (CMEs) are the brightest manifestations of solar activity. During periods of higher solar activity, dozens of ejections are observed daily and affect cosmic ray fluxes in interplanetary space. Observation of CMEs is usually carried out by means of various satellite apparatuses. In this work, features of the investigation of c...

An experiment on the measurements of the Cherenkov light yield from inclined cosmic ray muon bundles in water is being conducted at the Experimental complex NEVOD (MEPhI). The total number of Cherenkov photons is nearly proportional to the muon energy deposit (including secondary particles produced by muons and cascades from them) within the detect...

A description of the detection and data-acquisition systems of the Cherenkov water calorimeter of the NEVOD Experimental Complex, which is a unique scientific facility located on the Earth’s surface, is presented. In the development of these systems, a solution is sought to the problem of measuring the energy of cascade showers initiated by single...

Multiwire drift chambers designed for the neutrino experiment at the IHEP U-70 accelerator have found a new application in the MEPhI experiment focused on the detection of ultrahigh-energy cosmic rays. Their high durability and fine spatial and angular characteristics make these chambers perfectly suitable for such studies. The drift chambers were...

As part of an in-depth investigation of the muon excess observed in ultrahigh-energy cosmic rays, one needs to measure the energy characteristics of muon component of extensive air showers (EAS). The mean muon energy can be estimated from the energy deposited in the detector by the muon bundles. In the NEVOD–DECOR experiment, the local muon density...

The results of experiments of the last decades have shown that with the increase of energy of primary cosmic rays a clear excess of muon groups in comparison with the existing models of extensive air shower development (even assuming pure iron composition of PCR) appears. The problem is called 'muon puzzle' and it can be explained either by cosmo-...

A new NEVOD-EAS array for detection of extensive air showers (EAS) in the energy range 10¹⁵–10¹⁷ eV is being created in MEPhI (Moscow, Russia) on the basis of the Experimental complex NEVOD. It will be operated in conjunction with the Cherenkov water detector NEVOD and coordinate detector DECOR, as well as with detectors URAN and TREK which are now...

In 2014, the creation of a new cluster type shower array NEVOD-EAS was started around the Cherenkov Water Detector NEVOD and coordinate detector DECOR. The shower array will allow to determine the size, axis position and arrival direction of EAS registered by these detectors. In 2015–2016, the NEVOD-EAS central part, including 4 clusters of scintil...

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 considerabl...

The neutron component of EAS has not been practically studied for many years. Creation of the neutron detector arrays PRISMA-32 and PRISMA-YBJ demonstrated the effectiveness of such investigations. It is important to underline that recording the EAS neutron component is carried out over the whole array area. Development of a new larger scale neutro...

The large-scale coordinate-tracking detector TREK for registration of inclined EAS is being developed in MEPhI. The detector is based on multiwire drift chambers from the neutrino experiment at the IHEP U-70 accelerator. Their key advantages are a large effective area (1.85 m2), a good coordinate and angular resolution with a small number of measur...

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 b...

The NEVOD-EAS array is now being installed at MEPhI to determine the sizes, directions of arrival, and positions of the axes of extensive air showers (EAS), different components of which are recorded by the detectors of the NEVOD experimental complex. The central part of the NEVOD-EAS array, which contains four clusters of scintillation detector st...

A coordinate tracking unit based on drift chambers (CTUDC) for registering single muons and muon bundles at large zenith angles is created at the MEPhI. The unit consists of multi-wire drift chambers (DCs) with large drift gaps. These DCs were used earlier for the neutrino channel on the U-70 accelerator. The CTUDC consists of two coordinate planes...

The design for the TAIGA-HiSCORE array, a part of the TAIGA Gamma Ray Observatory, is considered. The observatory is being constructed in the Tunka Valley, 50 km from Lake Baikal. Preliminary results obtained using the first 28 optical stations of the array are presented.

Experimental data on the energy deposits of muon bundles in inclined extensive air showers (EASes), obtained at the NEVOD–DECOR installation over a long period of time, are presented. The experimental data are compared to calculations based on simulating an EAS’s muon component using the CORSIKA code.

The URAN array is designed to study primary cosmic rays in the region of the knee by detecting neutrons produced as a result of interaction between EAS particles and nuclei in the atmosphere or matter near the installation. It consists of 72 detectors mounted on the roofs of experimental buildings and combined into cluster structures of 12 detector...

Coronal mass ejections are the brightest manifestations of solar activity. Dozens of coronal mass ejections are observed daily during periods of higher solar activity. They directly affect cosmic ray fluxes that carry information on plasma clouds, including clouds moving toward the Earth. Several aspects of geoeffective and non-geoeffective coronal...

Cosmic ray muons are formed in the upper layers of the atmosphere under the effect of primary cosmic radiation, and their flux is sensitive to variation in atmospheric parameters. Thunderstorms are a pronounced manifestation of nonstationary processes in the atmosphere, and they are good material for developing and testing the main approaches to in...

In passing through the heliosphere, the cosmic ray flux changes its properties (energy and angular distribution) due to the influence of interplanetary medium. As a consequence, the muon flux generated by primary cosmic rays in the Earth’s atmosphere changes its properties as well. Muons detected on the Earth’s surface are mostly generated by prima...

Simulations of how secondary components of cosmic rays are generated and pass through the atmosphere are performed using the CORSIKA software package. The relationship between the vertical projection of the local anisotropy vector AZ and the index of primary particle spectrum γ is calculated. The time series of AZ for 2007–2015 are obtained using d...

Local muon density spectra (LMDS) at various zenith angles have been reconstructed from the data of two detectors of the Experimental complex NEVOD. The inclined muon bundles at the ground level were detected with the coordinate detector DECOR, and for the near-vertical direction with the calibration telescope system (CTS) of the Cherenkov water de...

The spatial distribution of Cherenkov radiation from cascade showers generated by muons in water has been measured with Cherenkov water calorimeter (CWC) NEVOD. This result allowed to improve the techniques of treating cascade showers with unknown axes by means of CWC response analysis. The techniques of selecting the events with high energy cascad...

Results of investigations of the near-horizontal muons in the range of zenith angles of 85-95 degrees are presented. In this range, so-called "albedo" muons (atmospheric muons scattered in the ground into the upper hemisphere) are detected. Albedo muons are one of the main sources of the background in neutrino experiments. Experimental data of two...

Muon hodoscope URAGAN allows to obtain the angular distribution of the muon flux. This distribution may be characterized by a vector of local anisotropy (the sum of the vectors of the particle arrival directions, normalized to the total number of muons). It was shown that annual variations in the vertical projection of the anisotropy vector A Z are...

Observations of gamma rays up to several 100 TeV are particularly important to spectrally resolve the cutoff regime of the long-sought Pevatrons, the cosmic-ray PeV accelerators. One component of the TAIGA hybrid detector is the TAIGA-HiSCORE timing array, which currently consists of 28 wide angle (0.6 sr) air Cherenkov timing stations distributed...

In 2014, the creation of a new cluster type shower array NEVOD-EAS was started around the Cherenkov Water Detector NEVOD and coordinate detector DECOR. The shower array will allow to determine the size, axis position and arrival direction of EAS registered by these detectors. In 2015–2016, the NEVOD-EAS central part, including 4 clusters of scintil...

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 considerabl...

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 b...

The neutron component of EAS has not been practically studied for many years. Creation of the neutron detector arrays PRISMA-32 and PRISMA-YBJ demonstrated the effectiveness of such investigations. It is important to underline that recording the EAS neutron component is carried out over the whole array area. Development of a new larger scale neutro...

The large-scale coordinate-tracking detector TREK for registration of inclined EAS is being developed in MEPhI. The detector is based on multiwire drift chambers from the neutrino experiment at the IHEP U-70 accelerator. Their key advantages are a large effective area (1.85 m2), a good coordinate and angular resolution with a small number of measur...

According to CACTus catalog, during periods of a high solar activity every day up to tens of coronal mass ejections are observed. Such ejections have an impact on the flux of cosmic rays that permeate the space around us. Unlike most ground cosmic ray detectors, muon hodoscope URAGAN (MEPhI) allows to investigate not only the integrated counting ra...

Experimental complex (EC) NEVOD includes a number of unique experimental facilities for studies of main components of cosmic rays on the Earth's surface. The complex is used for the basic research of CR flux characteristics and their interactions in the energy range 10^15 - 10^19 eV, and for applied investigations directed to the development of met...

A new cluster type shower array NEVOD-EAS is designed for estimating the size, axis position and arrival direction of extensive air showers registered by the Cherenkov water detector NEVOD and coordinate detector DECOR (Moscow, Russia). In 2015-2016, the central part of the array was deployed and started its operation. It includes 4 independent clu...

Change of the energy characteristics of muon bundles with an increase of the primary cosmic ray particles energy can be a key to solving the problem of muon excess in the extensive air showers (EAS) observed in a number of experiments. In this work the data on the energy deposit of multi-muon events in a wide range of zenith angles (and as a conseq...

Change of the energy characteristics of muon bundles with an increase of the primary cosmic ray particles energy can be a key to solving the problem of muon excess in the extensive air showers (EAS) observed in a number of experiments. In this work the data on the energy deposit of multi-muon events in a wide range of zenith angles (and as a conseq...

A cluster type NEVOD-EAS setup is being constructed by the National Research Nuclear University MEPhI on the basis of the Unique Scientific Facility “Experimental Complex NEVOD”. The NEVODEAS setup is intended for the detection of extensive air showers (EASs) with energies in the region of the knee in the energy spectrum of primary cosmic rays (10¹...

We present physical motivations and advantages of the new gamma-observatory TAIGA (Tunka Advanced Instrument for cosmic ray physics and gamma-ray astronomy). TAIGA will be located in the Tunka valley, 50. km to the west of Lake Baikal, at the same place as the integrating air Cherenkov detector for cosmic rays Tunka-133. The TAIGA array is a comple...

The flux of charged primary cosmic rays (PCR) is modulated by changes of interplanetary magnetic field which depend on various heliospheric processes. After interaction of PCR with nuclei of atoms of the Earth's atmosphere, these modulations are transferred to a flux of secondary muons. Muon hodoscope URAGAN allows to trace changes not only of inte...

Results of the studies of cosmic ray muon flux variations during the powerful Forbush effect registered by the muon hodoscope URAGAN on June 22, 2015 are presented. From the muon flux angular distribution, the dependence of the intensity decrease amplitude on the primary particle energy in the region above 10 GeV has been obtained. The changes of t...

The new scintillation muon hodoscope to study cosmic ray muon flux variations was created in MEPhI. The basic characteristics of the hodoscope (sensitivity area, precision of the muon track reconstruction, 'live' time etc.) are comparable with other hodoscopes (TEMP and URAGAN) of MEPhI. Modular design is a distinctive feature of the detector, supp...

The project of a new setup is directed at the registration of atmospheric neutrons (URAN) generated by hadronic component of extensive air showers (EAS). The setup includes 72 en-detector which simultaneously register two major EAS components: electromagnetic by the group passage of charged particles and hadron component by the thermal neutrons. Th...

The coronal mass ejection (CME) that occurred on April 28, 2015 is analyzed. The passage of the ejection did not cause geoeffective disturbances in the near-Earth space. At the same time, the CME had a significant impact on the flux of cosmic rays registered on the Earth's surface by the muon hodoscope URAGAN.

The TAIGA project is aimed at solving the fundamental problems of gamma-ray astronomy and physics of ultrahigh energy cosmic rays with the help of the complex of detectors, located in the Tunka valley (Siberia, Russia). TAIGA includes a wide-angle large area Tunka-HiSCORE array, designed to detect gamma-rays of ultrahigh energies in the range 20 -...

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 m...

Experimentally obtained energy characteristics of the muon flux during Forbush decreases registered by means of the muon hodoscope URAGAN at different phases of 23rd and 24th solar cycles are studied. To obtain the energy spectra of Forbush decrease amplitudes in the flux of the primary particles, coupling functions of the primary and the secondary...

Measuring system of scintillation muon hodoscope with WLS light collection for the study of the processes in the heliosphere and terrestrial atmosphere is described. Procedures of testing and adjusting of basic modules and muon hodoscope as a whole are presented.