• Ешқандай Нәтиже Табылған Жоқ



Academic year: 2023

Share "View/Open"


Толық мәтін

The study of Ultra High Energy Cosmic Rays (UHECR) arriving at Earth from deep space has the potential to unravel some of the remaining mysteries in the field of High Energy Physics and Astrophysics. The simulation activities show the existence of "invariant" properties of the EAS standard as determined by the CORSIKA simulator. The definition of this invariant property, its test using data, and the classification of EAS events from Physics Run 1 are described in this thesis.

He observed that the level of ionizing radiation is higher at a higher altitude in the atmosphere and concluded that the source of the radiation is in outer space [5]. Important stages in the development of the study of cosmic rays were the discoveries of Geiger-Müller counters by H. The cloud chamber experiments led to the discoveries of the positron in 1932, and later, in 1937 of the muon by C.

Auger came to the conclusion that the registered particles were created in the atmosphere and originated from a single cosmic ray particle. The first experiments to study the structure of EAS were carried out by Bruno Rossi in the USA and G.

Cosmic rays

  • Electromagnetic interactions
  • Muonic interactions
  • Longitudinal development
  • Lateral development
  • Random walk

A large number of these particles overlap to form a single giant cascade called an extensive air shower (EAS). A primary particle, such as a proton or a nucleus, collides with the nuclei of oxygen or nitrogen atoms in the atmosphere and produces a multitude of secondary particles through the hadronic interaction. Charged particles, mainly electrons and positrons, and photons, which form the electromagnetic component of the EAS, are responsible for electromagnetic interactions in the atmosphere.

According to Heitler's model, particles (𝑒+, 𝑒− and photons) undergo repeated splittings of two bodies in the interaction with the atmosphere. After each interaction, two particles travel a fixed distance𝜆𝐸𝑀 through the atmosphere and carry half the energy of the original particle. Produced particles propagating over a certain depth in the atmosphere reach a certain number which can be represented as follows.

It also describes the logarithmic increase of maximum atmospheric propagation depth with the energy of a primary particle. Following the simple model of EAS evolution, the total number of muons will be As an EAS develops through the Earth's atmosphere, the number of secondary particles grows exponentially and is reduced at sea level.

Particle density distribution is dependent on the energy of a primary particle which can be calculated by knowing the radius of an EAS. If considering the atmosphere sliced ​​into slices of thickness 20𝑔/𝑐𝑚2, the number of particles in each atmospheric slice will characterize the longitudinal development of the EAS, which is demonstrated in Fifure 3-1. All these particles are created in multiple interactions in the atmosphere and cause the formation of three main shower components described in previous section (hadronic, electromagnetic, muonic).

Lateral development of EAS at high mountain levels can cover large areas (up to a few kilometers), which is dependent on energy of a primary particle or EAS size. Far from the core, low-energy particles of muonic and electromagnetic components dominate the shower. Another EAS characteristic suggested by simulation is broadening of an EAS disk, which can be defined as a difference in the transit time of an EAS disk.

The disc arrival time difference is defined as the peak width of the EAS particles arriving at a given detector area. The delay occurs as a result of an increase in the number of particle dispersion processes in the atmosphere and as a result of propagation fluctuations along their path.

Simulation results

Using the relationships between EAS characteristics discussed in Section 3.1, simulated EAS were tested for the invariant property𝜌0.5(𝑅)*𝜏(𝑅)which was derived from random walk theory. As a result, this theoretical suggestion was only confirmed for the simulation of EAS using a detector of size 10×10𝑚2. The value of 𝜌0.5(𝑅)*𝜏(𝑅) is found to be relatively constant only at a distance interval of 200 - 450 meters from the EAS axis.

When the EAS is tilted at a certain angle, the invariant property is not observed. The HorizonT (HT) detector system is a cosmic ray detector system located at a high altitude (~3500 meters above sea level) in the Tian Shan Mountains near Almaty, Kazakhstan. HT is part of the Tian Shan High-altitude Science Station (TSHASS) of the Lebedev Institute of Physics of the Russian Academy of Sciences.

There are three Vavilov-Charenkov radiation detectors and eight charged particle (scintillator and glass) detection points, separated by a distance of about one hundred meters. Table 4-1 shows the distance from the coordinate positions of the detection points to the central detection point. In the HT detector system, each detector is connected to the data collection system located at detection point 1 (Center) via cables.

SC detectors are calibrated using their minimally ionizing particle (MIP) response signal from the cosmic ray flux. In this thesis, the calibration of the time delay in each cable and the signal loss are considered as well as their MIP response values ​​[14, 15]. Light is registered by PMT placed above the center of detection medium at the height 1 m for the scintillator and 0.5 m for glass.

Each detection point has both SC and GD detectors equipped with 2 types of photomultiplier tubes (PMT) [11]. SC and GD detectors are equipped with Hamamatsu R7723 PMT [17, 12] assembly, plastic skinner with MELZ FEU49 PMT [18, 12], glass with R7723 PMTs and also Vavilov-Cherenkov radiation detector equipped with both. SC detectors' response is calibrated (see Appendix A) using MIP (minimum ionizing particle) including uncertainty caused by loss and broadening of a signal in cables.

Data analysis and classification

  • Standard EAS
  • Testing and verification of simulation results on data
  • Multimodal EAS
  • Statistics

About 2000 EAS events were selected from the total set of events detected between January 2017 and April 2017 on the Horizon-T detector system. It can be seen that the axis of the shower traveled from the top side of the detector and arrived near the center of the detection point where the highest peak is shown. All pulses have a single-mode smooth shape that does not change with distance from the EAS axis.

From the analysis results, it is seen that peak area or particle density in MIP decreases as 1/𝑟2 at the ~ 150 meters from the axis (see Figure 4-6). Of the total number of ~2000 EAS events collected in Physics Run I, about 500 can be defined as standard. Therefore, we use the concept of the axis conditionally, when the shower axis is determined from the time of passage through the installation.

These peaks are visible at the detection points Kurashkin and Left at relatively the same distance from the axis. They are located at the farthest location from the EAS axis and separated from each other by hundreds of ns. From the EAS display, a very large signal is visible at the detection point to the left, indicating that the EAS has arrived close to this point.

Future pulses that are closer to the axis (Kurashkin, Right, Center) begin to deviate from the smooth shape. From the detection configuration, it can be concluded that the radius of the EAS event is ~1 km. Among the data detected during Physics Run I of the HT detector system operations, two main types of EAS were observed.

From the theory of EAS, it has been suggested that there is a possible invariant property that can be used as a characterization of EAS, and consequently as a new method in data analysis. The important fact is that standard EAS events are observed at the energy range from 1016eV and below. As the result of this study, invariant property was not confirmed in data in standard EAS event data.

This is the partial event because the largest peak (left detection station) has a pulse structure that deviates from the standard normal. Hörandel, "Cosmic Rays from the Knee to Higher Energies," Progress in Particle and Nuclear Physics, vol.

Ақпарат көздері



With the help of such methods as a comprehensive analysis of the essence and structure of the information component of modern culture, based on the application of an interdisciplinary