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Neutral Meson Production in Ag+Ag Collisions at 1.58 A GeV with HADES Electromagnetic Calorimeter
Prozorov, Alexandr ; Kugler, Andrej (advisor) ; Bielčík, Jaroslav (referee) ; Závada, Petr (referee)
Title: Neutral Meson Production in Ag+Ag Collisions at 1.58 A GeV with HADES Electromagnetic Calorimeter Author: Alexandr Prozorov Abstract: The Dielectron Spectrometer HADES operating at the SIS18 synchro- tron, FAIR/GSI Darmstadt, recently provided new intriguing results on the pro- duction of electron pairs and strangeness from nucleus-nucleus collisions, as well as from elementary reactions, in the energy region of 1 − 2 A GeV. In 2019 the spectrometer was complemented by an electromagnetic calorimeter based on lead- glass modules, which allows us to measure photons and thus study the production of π0 and η mesons via their two-photon decay. Knowledge of the neutral-meson production is a mandatory prerequisite for the interpretation of dielectron data. In particular, the directed and elliptic flow of neutral mesons with respect to transverse momentum and rapidity will be shown for different centrality classes in Ag + Ag collisions at 1.58 A GeV. The results of the analysis corresponding to the 14 × 109 events will be confronted with the results of other experiments and with the current model calculations. Keywords: baryonic medium, hadrons, relativistic heavy-ion collisions, neutral mesons, pion flow
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Study of transverse flow of kaons in Au+Au collisions at 1.23A GeV
Chlad, Lukáš ; Kugler, Andrej (advisor) ; Dolejší, Jiří (referee) ; Závada, Petr (referee)
Title: Study of transverse flow of kaons in Au + Au collisions at 1.23A GeV Author: Lukáš Chlad Abstract: The production and propagation of strange hadrons at the threshold energy are important probes of the in-medium hadron's properties and stiffness of the equation of state of nuclear matter. In this thesis, the transverse kaon flow at Au + Au collisions with kinetic beam energy 1.23A GeV measured with the HADES spectrometer is discussed. The motivation for such an analysis and the theoretical introduction are described first, followed by the characterization of the the individual parts of HADES spectrometer. The procedure to identify detected particles from the measured signals is introduced. Finally, the flow analysis and its results are presented. The differential directed and elliptic flow of kaons in measured gold on gold collisions is compared with published data and with kinetic transport model predictions. Keywords: relativistic heavy-ion collisions, transverse flow, kaon flow 1
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Measurements and usage of cross sections of various (n,chi n) threshold reactions
Chudoba, Petr ; Vrzalová, Jitka ; Svoboda, Ondřej ; Krása, Antonín ; Kugler, Andrej ; Majerle, Mitja ; Suchopár, Martin ; Wagner, Vladimír
Current trend in nuclear reactor physics is a transition from technologies using thermal neutrons to technologies utilizing fast neutrons. Unfortunately focus was put mainly on the thermal neutrons for a long time and lead to very good knowledge about this low energy region, but very scarce coverage of the high energy region. This means that there is a gap in the knowledge of excitation functions for higher energies. This gap spreads from 20 MeV up to 1 GeV and higher. This is exactly the energy region needed for description of advanced nuclear systems such as accelerator driven systems (ADS). Our group from Nuclear Physics Institute (NPI) of the CAS is a member of an international collaboration Energy & Transmutation of Radioactive Waste (E&T RAW). This collaboration focuses on ADS for many years. In order to measure neutron field within ADS models it is necessary to know excitation functions of reactions used to monitor the neutron field. In many cases there are almost no experimental data for suitable reactions. Worse and quite common case is that there are no data at all. Therefore we are also focusing on measurements of these data in order to fill the databases as well as to allow further improvements of codes for nuclear data calculations.
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Application of Pulse-Shape Discrimination Method for Wide Aperture Si-Detectors
Sobolev, Yuri, G. ; Tyurin, G. P. ; Damyanova, A. S. ; Danilov, A. ; Khlebnikov, S. V. ; Kugler, Andrej ; Ogloblin, A. A. ; Penionzhkevich, Y. E. ; Trzaska, W. H.
A method for the identification of charged particles by wide aperture Si -detectors has been investigated based on the employment of pulse -shape discrimination in a silicon p-i-n detector.
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A new set-up for total reaction cross section measuring
Sobolev, Yuri, G. ; Ivanov, M. P. ; Kugler, Andrej ; Penionzhkevich, Y. E.
The experimental method and set-up based on 4 P n-gamma-technique for direct and model-independent measuring of the total reaction cross section sigma(R) have been presented. The excitation function sigma(R)(E) for He-6+Au-197 reaction at the Coulomb barrier energy region has been measured. The measured data are compared with the summarized cross section which has been prepared by summing of measured cross sections of main reaction channels: 1n-transfer and Au-197(He-6, xn)Tl203-xn with x = 2 divided by 7 evaporation reaction channels.\n\n
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HADES - STUDIUM ZMĚN VLASTNOSTÍ HADRONŮ
Chlad, Lukáš ; Kugler, Andrej (advisor) ; Soustružník, Karel (referee)
During the summer 2014, the HADES collaboration had the opportunity to measure pion collisions with different nuclei. These measurements were done with two objectives. The first being the investigations of hadrons with strange quarks and their behaviour at normal nuclear density. The analysis of this will concentrate specifically on φ meson and Λ baryon production. The focus on properties of baryonic resonances in the region of N(1520) and N(1535) formed the second objective. Special emphasis is put on beam line detectors which use different particle detection techniques. In particular, the scintillator based Hodoscope and diamond based Start detector will be discussed. There is also presented the analysis of π + p elastic scattering which is important for normalisation of the cross section of the reactions of interest. The measured elastic scattering yields are compared with dedicated simulations and previously published data. 1
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Study of calorimetr to be used in heavy ion physics
Chlad, Lukáš ; Kugler, Andrej (advisor) ; Spousta, Martin (referee)
The purpose of this bachelor thesis is to apprise reader with the basics of mea- suring energy of particles with calorimeter which are being created in collisions on particle and heavy ion colliders. This research is mentioned in chapters 1 and 2. Another object is presentation electromagnetic and hadron calorimeters for accelerator complex GSI and FAIR in Darmstadt, Germany. There are men- tioned in particular moduls for ECAL and PSD calorimeter and also the read out electronic. The results and the description of modul testing are presented in chapter 3. 1
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Production of neutrons in reaction of relativistic protons on thick or how to burn the nuclear waste by accelerator
Krása, V. ; Wagner, Vladimír ; Belina, L. ; Henzlová, D. ; Henzl, V. ; Kugler, Andrej ; Adam, Jindřich ; Čaloun, Pavel ; Krivopustov, M. I. ; Tumendelger, Th.
We look for the way how to burn the nuclear waste by the transmutation of radioactive nuclei by the fast neutrons produced by proton beam.
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Heavy-ion collisions: The study of elliptic flow of neutral mesons in Au+Au reaction at 800 A MeV
Pleskač, Radek ; Kugler, Andrej ; Tlustý, Pavel ; Wagner, Vladimír ; Hlaváč, S.
The combination of the photon spectrometer TAPS - an electromagnetic calorimeter with good energy, time and spatial resolution - and the charged particle-detecting KAOS Forward Wall (FW) offers the possibility to study azimuthal distribution of neutral mesons relative to the reaction plane. The experimental data from the Au+Au reaction at 800 MeV were analyzed. The reaction plane was determined on an event by event by event basis and angular distribution of ă.sup.o./sup. and .eta. mesons was reconstructed. The observed elliptic flow signal is negative for .eta. mesons, indicating a preferred emission perpendicular to the reaction plane. The elliptic flow for ă.sup.o./sup. mesons is significantly observed in peripheral Au+Au collisions only.
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Electron-positron pair production in nuclear matter - first data from HADES
Tlustý, Pavel ; Kugler, Andrej ; Pleskač, Radek ; Wagner, Vladimír ; Suk, M. ; Hlaváč, S. ; Žovinec, D.
Study of hadron properties inside nuclear matter at normal and high temperatures and baryon densities represents one of important topics of the present nuclear research. Several models predict change of effective masses and widths of hadrons due to the chiral symmetry restoration at extreme conditions of the nuclear matter. Existing experimental data do not allow unambiguous conclusions with respect to medium modifications due to the limited invariant mass resolution and separation. To improve and extend the existing experimental evidence the new High Acceptance DiElectron Spectrometer HADES was build at GSI, Darmstadt.
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