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Study of high energy cosmic gamma rays
Štefánik, Stanislav ; Nosek, Dalibor (advisor) ; Soustružník, Karel (referee) ; Tománková, Lenka (referee)
In this thesis, we present our two studies focused on the detection of cosmic γ-rays and the analysis of data from γ-ray observations. One study deals with the method of the Cherenkov transparency coefficient. This method is suitable for the detector calibration in experiments employing imaging atmo- spheric Cherenkov telescopes for the indirect detection of cosmic γ-rays. Us- ing rates of recorded air showers initiated by charged cosmic rays, the method aims at the monitoring of the atmospheric transparency to Cherenkov light and the calibration of the responses of Cherenkov telescopes. We present an extension of this method for the purposes of the Cherenkov Telescope Array observatory and demonstrate its feasibility using Monte Carlo simu- lations. Our other analysis utilizes more than 7 years of data from direct γ-ray observations by the Fermi Large Area Telescope. We describe in detail signal observed from the parts of the sky around the active galactic nuclei 1ES 0229+200 and Centaurus A. We report on the findings of new astro- physical sources of high energy photons and document spectral and temporal properties of their γ-ray fluxes. 1
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Cosmic ray study in the Belle II silicon detector
Kapitánová, Lucia ; Doležal, Zdeněk (advisor) ; Sýkora, Martin (referee)
This thesis introduces validation and monitoring tools developed and adjusted for the Belle II vertex detector used during the VXD commissioning run in October and November of 2018. The introductory review part introduces the Belle II detector and provides detailed description of the vertex silicon detector, its components and their functions. Subsequently, the software reconstruction methods are introduced and the applied alignment procedure is explained in the third section. The major focus of this thesis is presentation of validation and monitoring results as well as qualitative description of the measurement precision improvement using cosmic muons trajectories reconstructed in the vertex detector. The last part introduces a new tool for estimation of alignment parameters using monitoring and validation methods. The main purpose of this newly proposed method is to provide fast and credible information about the current alignment status to experts using this data.
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The effects of ionizing radiation on semiconductor devices properties
Yermalayeva, Darya ; Šteffan, Pavel (referee) ; Musil, Vladislav (advisor)
This master’s thesis deals with the problematics of influence of ionizing radiation on semiconductor devices and their properties. The aim of the thesis is to analyze the different types of radiation that can occur in the areas of application of these components. In the second part, the degradation processes are explored, with emphasis on the influence caused by the radiation dose. Also, the displacement damage and SEE effects are described, but just slightly, because they are not part of this work. The third part describes the device design process and harmful effects, that have to be considered during the design phase. In the forth and the fifth parts of this work were done modeling of radiation effects (influence of dose rate, Single-Event Upset and Total Ionizing Dose) in PSpice program and was carried out the possibility of designing a simple dosimeter with silicon diode. In conclusion, the results of the thesis are summarized and evaluated.
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Phenomenological models inspired by QCD and their use in the analysis of ultra-high energy cosmic rays
Ebr, Jan ; Řídký, Jan (advisor) ; Leitner, Rupert (referee) ; Unger, Michael (referee)
Cosmic rays of energies above 1014 eV are detected mostly indirectly, by observing the extensive air showers they create in the atmosphere. Multiple experiments suggest that the current models of high-energy interactions do not describe the cosmic ray data perfectly, in particular when it comes to the prediction for the number of muons at ground. We present two models aiming to improve the description of the muon component, one based on the addition of particles with small momenta in the local center-of-mass frame of the high-energy hadronic interactions in the shower, the other on the addition of the so-called dark photons to the electromagnetic part of the shower. While we find the latter having no observable consequences, the former improves the agreement between observed and predicted amounts of muons both for the DELPHI cosmic ray data and for the measurements by the Pierre Auger Observatory. We also describe the FRAM telescope, a device used to monitor the atmosphere at the Pierre Auger Observatory, and its applications to the search for anomalous shower profiles and to the measurement of the aerosol content of the atmosphere, which is crucial for the analysis of data obtained by fluorescence detectors. 1
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Study of Interactions of Cosmic Rays at Ultra-high Energies
Nečesal, Petr
This thesis is dedicated to study of interactions of utra-high energy cosmic rays using measured data from the Pierre Auger Observatory, automatic alarm system called Shift Guard and analysis of correlation of temperature and detector response. The Pierre Auger Observatory is the largest experiment to study ultra-high energy cosmic rays. The assumed relation between temperature and fluorescence detector response is studied together with descriptive temperature analysis, which shows that the air-conditioning system is not able to stabilize temperature enough. The temperature influence on camera response is investigated in order to measure the calibration correction factor. Shift Guard - the alarm system dedicated to protect fluorescence detectors and data taking is introduced and its functionality is described. The alarm system informs shifters about some events and situations that can endanger detector or deteriorate data quality. The basic parameters and alarm system logic are described together with light and sound signals. The discrepancy between measured and predicted number of muons at ground level calculated by EAS generators is showed and possible sources of this disagree- ment are studied. The result of massive dark photons decay in EAS as one of exotic muon source is presented. The analysis...
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Study of Interactions of Cosmic Rays at Ultra-high Energies
Nečesal, Petr ; Řídký, Jan (advisor) ; Vorobel, Vít (referee) ; Wagner, Vladimír (referee)
This thesis is dedicated to study of interactions of utra-high energy cosmic rays using measured data from the Pierre Auger Observatory, automatic alarm system called Shift Guard and analysis of correlation of temperature and detector response. The Pierre Auger Observatory is the largest experiment to study ultra-high energy cosmic rays. The assumed relation between temperature and fluorescence detector response is studied together with descriptive temperature analysis, which shows that the air-conditioning system is not able to stabilize temperature enough. The temperature influence on camera response is investigated in order to measure the calibration correction factor. Shift Guard - the alarm system dedicated to protect fluorescence detectors and data taking is introduced and its functionality is described. The alarm system informs shifters about some events and situations that can endanger detector or deteriorate data quality. The basic parameters and alarm system logic are described together with light and sound signals. The discrepancy between measured and predicted number of muons at ground level calculated by EAS generators is showed and possible sources of this disagree- ment are studied. The result of massive dark photons decay in EAS as one of exotic muon source is presented. The analysis...
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Studium urychlování vysokoenergetických částic v extragalaktických objektech
Štefánik, Stanislav ; Nosek, Dalibor (advisor) ; Vorobel, Vít (referee)
Title: Study of Cosmic-Ray Acceleration in Extragalactic Objects Author: Stanislav tefnik Department: Institute of Particle and Nuclear Physics Supervisor: RNDr. Dalibor Nosek, Dr. Abstract: This thesis deals with production processes of cosmic γ-rays in astro- physical objects and methods of their detection. Possible interactions leading to the emission of high energy γ-rays in the active galaxy Centaurus A are discussed in this context. Cherenkov Telescope Array is presented as a new experiment fo- cused on the detection of air showers initiated by cosmic γ-rays. Cherenkov light of air showers is studied in the simulations done by CORSIKA simulation tool. Method of data analysis within the framework of Cherenkov telescopes is descri- bed and performed on the dataset of the active galaxy PKS 2155-304. The results include statistical tests of γ-ray source presence and its time variability. Keywords: Cosmic rays, gamma rays, astroparticle physics, high energy astro- physics, acceleration, CTA experiment
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Study of correlations of cosmic ray showers detected by the CZELTA detection network and gamma-ray bursts
Hubík, Jan ; Smolek, Karel (advisor) ; Suk, Michal (referee)
The origin of high energy cosmic rays is still unknown. High energy cosmic rays can be associated with high energy gamma ray bursts. In the presented work we briefly summarize subject of cosmic rays and gamma ray bursts, including their detection methods. Using statistic methods we study time and directional correlations of cosmic ray showers measured by detection array CZELTA with gamma ray bursts detected by satellite experiments. Presented work provides detailed description of used analysis methodology. We were unable to demonstrate link between described phenomena.
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Kalibrace fluorescenčních detektorů kosmického záření s použitím astronomických metod
Kotíková, Irena ; Prouza, Michael (advisor) ; Šmída, Radomír (referee)
This diploma thesis examines the possibilities of a new method of astronomical calibration at the Pierre Auger Observatory in Argentina. Its goal is to use stars as objects with known brightness to calibrate the fluorescence detectors and compare these results with the existing calibration. The analysis was done using computer programs which use the star catalog and experimental background data to compare the current calibration with our method. Results that are presented conclude that the calibration using stars is consistent with the existing calibration, however, the error of the new method is much higher. Nevertheless, there is a good potential for scale - it could be used for all past and future data. Potential improvements to this method and its error are suggested.
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Study of cosmic gamma rays
Štefánik, Stanislav ; Nedbal, Dalibor (advisor) ; Nosek, Dalibor (referee)
Title: Study of cosmic gamma rays Author: Stanislav Štefánik Department: Institute of Particle and Nuclear Physics Supervisor: Mgr. Dalibor Nedbal, Ph.D. Supervisor's e-mail address: nedbal@ipnp.troja.mff.cuni.cz Abstract: This thesis is focused on elementary knowledge of cosmic γ ray physics. In the introduction there is provided history overview of astroparticle physics, cosmic ray features and interactions are discussed. The remainder of the thesis deals with detection of cosmic γ rays with emphasis put on Čerenkov method of air shower detection. In this context the H.E.S.S. experiment in Namibia is presented and the technique of data acquisition and processing is described as well. Result of this thesis is to understand modern analysis methods used for study of cosmic rays as well as application of this method on simulated and real data acquired by H.E.S.S. Keywords: cosmic rays, gamma rays, astroparticle physics, H.E.S.S.
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