Abstract
In the classification of the Ministry of Science and Higher Education in the National Project “Nauka” (2018), the concept of MegaScience is the name of a class of unique scientific ...installations, and in general terms, these are large expensive international scientific and research complexes for solution of actual scientific problems. It is emphasized that world-class breakthrough research is impossible within the framework of one university or organization, without attracting multi-billion budgets. However, the practice of MEPhI shows that it is possible to construct the unique scientific installations and to achieve results comparable to the largest international projects within a university in cooperation with other Russian and foreign organizations.
The new coordinate-tracking detector TREK based on drift chambers is being developed at National Research Nuclear University MEPhI to study inclined extensive air showers. To reconstruct the events ...with a high multiplicity from the data of drift chambers, the histogram method, which is designed to search for parallel tracks, is currently used. However, we observe afterpulses in the experimental data obtained using a coordinate-tracking unit based on drift chambers (CTUDC). The afterpulses lead to fake track reconstructions. To solve this problem, a new method is being developed using deep learning. This paper presents the results of the development of this method and its application to simulated data.
The muon puzzle is an excess of muon bundles generated by primary cosmic rays (PCR) at energies above 10
eV compared to estimations that assume even a heavy composition of PCR. The appearance of such ...excess of muons can be caused both by cosmophysical (the change in the spectrum and composition of cosmic rays) and nuclear-physical (the changing features of the hadron interaction) reasons. To separate these two possibilities it is necessary to measure energy characteristics of muon bundles and their dependence on energy of primary particles. Today the complex NEVOD-DECOR is the only one for such type experiment conduction. To improve the conditions of this experiment a further development of the experimental complex is planned: construction of new coordinate-tracking detector TREK for increasing of the area and improving of spatial resolution of muon track detection, modernization of the Cherenkov water detector for optimization of its structure and improvement of accuracy of energy deposit of muon bundle measurement, inclusion of the installation NEVOD-EAS in the experiment for independent evaluation of primary particle energy.
The new coordinate-tracking detector TREK based on multiwire drift chambers is being developed in the National Research Nuclear University MEPhI to study the muon component of extensive air showers. ...Its prototype named the coordinate-tracking unit based on drift chambers (CTUDC) has been designed. Investigation of the multiparticle events registered by the unit has shown all the complexity of reconstruction of such events. The analytical reconstruction methods applied earlier demonstrate their inefficacy in dealing with these events. A new approach based on deep learning methods is being developed to solve this problem. The paper presents the results of application of artificial neural networks to experimental data obtained by the CTUDC.
Results are presented from analyzing multiparticle events in cosmic rays on coordinate-tracking setups on the CTUDC and ProtoTREK drift chambers. Analysis of the ProtoTREK data shows that multiwire ...drift chambers allow the reconstruction of events with densities of up to 15 particles per square meter. The energies of primary cosmic rays responsible for the generation of muon groups registered by the CTUDC installation are estimated.
NEVOD-DECOR is the unique experiment where systematic studies of cosmic ray muon bundles in a wide range of zenith angles and, accordingly, the energies of primary cosmic rays are carried out. ...Impressive experimental material (more than 100 thousand events) has been accumulated over a long time period from May 2012 to December 2022. The earlier developed method of local muon density spectra allows us to compare experimental data on muon bundles with the results of the EAS muon component simulations. 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 hadronic interaction models) only under the assumption of an extremely heavy mass composition. It is consistent with data of several other experiments on investigations of air shower muon content, but contradicts the available measurements of the depth of the shower maximum in the atmosphere by means of fluorescent technique, which favor a light mass composition at these energies. This probably leads to the need to revise the existing hadronic interaction models.
At the Unique Scientific Facility NEVOD (MEPhI), a large coordinate-tracking detector based on drift chambers for investigations of muon bundles generated by ultrahigh energy primary cosmic rays is ...being developed. One of the main characteristics of the bundle is muon multiplicity. Three methods of reconstruction of multiple events were investigated: the sequential search method, method of finding the straight line and method of histograms. The last method determines the number of tracks with the same zenith angle in the event. It is most suitable for the determination of muon multiplicity: because of a large distance to the point of generation of muons, their trajectories are quasiparallel. The paper presents results of application of three reconstruction methods to data from the experiment, and also first results of the detector operation.
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 primary particle energies of about 1018 eV and higher can be compatible with the expectation only under the assumption of an extremely heavy mass composition of cosmic rays. On the contrary, measurements of the depth of the shower maximum in the atmosphere in the experiments using air fluorescence technique, favour a light mass composition of primary cosmic rays at these energies.
Using virtual reality technology - a modern trend. The nuclear industry is no exception. This article provides an overview of mathematical models used to create virtual analogue of critical assembly ...Godiva in virtual reality. Godiva - there is a simple example that allows to hone techniques for creating more complex virtual analogues of nuclear reactors and nuclear facilities. Mathematical models include stationary and dynamic ones. The stationary model is based on data from calculations carried out using Monte Carlo programs such as MCU, Serpent and Geant4. An approach is also described that makes it possible to calculate the reverse multiplication from the values of the effective multiplication factor for various states of the subcritical assembly. The dynamic model allows one to calculate the neutron-physical characteristics of the supercritical assembly during fast processes such as a neutron burst. In conclusion, there are other examples of virtual analogs created using similar approaches.
The TREK large-scale coordinate tracking detector is being created at MEPhI on the basis of drift chambers for detecting the near-horizontal flux of muon bundles generated by ultrahigh-energy primary ...cosmic rays. The detector’s operation is modeled comprehensively in three stages to interpret experimental data: modeling an EAS in the CORSIKA environment, calculating interaction between EAS particles and the detector and its supporting structures in the Geant4 environment; and modeling of responses from drift chambers and on-chamber electronics in the Garfield ++ environment. Each stage of modeling is described, along with the exchange of data between them and the initial results.
PDF