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Simulation of dose distribution irradiation
Večeřa, Petr ; Hlaváč, Martin (referee) ; Kolářová, Jana (advisor)
This project deals with the issue of simulation of dose irradiation. This principle is used in a radiotherapeutic device known as a Leksell Gamma Knife for the treatment of intracranial tumours. With regard to the theoretical observations obtained by studying this device, the project suggests the use of analytical geometry for the creation of a mathematical model for calculation of the intensity in the rayed area. A demonstration program Leksell_xvecer08 has been created for this model in a MatLab software background, which enables the user to change various input arguments and simulate a picture of the dosage spread in the target scanned areas.
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Autonomous Robotic Gamma Radiation Measurement
Lázna, Tomáš ; Burian, František (referee) ; Žalud, Luděk (advisor)
Tato práce se zaměřuje na autonomní lokalizaci radiologických zdrojů v definované oblasti zájmu. Jejím cílem je vyvinout lokalizační strategie a platformu, na které je bude možné vyzkoušet. Platforma je sestavena z průzkumného robotu Orpheus-X3, scintilačních detektorů a přesného GNSS přijímače. Algoritmus pro vytváření mapy distribuce radiačního pole je rozšířen. Jsou představeny nové metody založené na směrové citlivosti navrhovaného detekčního systému. Počáteční průzkum oblasti zájmu je uskutečněn pomocí kružnicových trajektorií. Všechny algoritmy byly otestována jak simulacemi, tak reálnými experimenty. Dosažená přesnosti lokalizace je v řádu desítek centimetrů. Časová efektivita je použitím nových algoritmů zvýšena přibližně dvakrát až pětkrát. Jedním z~přínosů práce je vývoj modulárního systému, který může být přesunut a uzpůsoben na jiné platformy. Výhodou použitého systému je vysoký stupeň autonomie a bezpečnost pro lidského operátora.
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The AmBe Laboratory Neutron Source Field Determination Using Experimental Stend
Jelínek, Martin ; Šťastný, Ondřej (referee) ; Katovský, Karel (advisor)
This master’s thesis provides a comprehensive overview of the conventional neutron sources from the perspective of reactions which lead to the production of neutrons, advantages, disadvantages, properties and their possible utilization. In the relation to the assembly of the laboratory neutron source and the unique experimental stand “Candle” basic methods of the neutron field analysis are outlined and two of them, the neutron activation analysis and the calculation using the MCNP software code are discussed in depth to apply and compare these methods. The experimental part deals with the realization of neutron activation analysis from its design itself, through gamma spectrometry to the cadmium ratio calculation. In compliance with the measurements, a calculation with MCNP code was run and both methods were evaluated and compared. The computation is complemented with the analysis of radiation situation on the borders of the supervised area, which is compared to the legal limit.
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Digital signal processing using field programmable gate arrays
Vykydal, Jan ; Kubíček, Michal (referee) ; Kolka, Zdeněk (advisor)
This thesis deals with the design, implementation and testing of an equipment that performs spectral analysis of a gamma radiation, based on the evaluation of pulses from a scintillation detector. The pulzes are pre-amplified and digitized, and their further processing takes place numerically in an FPGA, which allows a simple modification of the function of the developed device. After an introduction to the issue of gamma radiation spectroscopy with a focus on its detection, the thesis is devoted to the development of a multichannel analyzer hardware, whose individual parts are further described later. Next, the development of a digital signal processing system in the FPGA is described. Followed by an analysis of a microcontroller firmware, and a text protocol for the controlling of the device. Finally, the results of the work are discussed, with a focus on the test measurement of gamma radiation.
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Shielding and detection of neutrons
Černý, Tomáš ; Šťastný, Ondřej (referee) ; Katovský, Karel (advisor)
The master’s thesis provides an overview of available neutron sources in terms of neutron yields and energy spectrum of emitted neutrons. Reactions of neutrons with matter, especially neutron scattering and radiation capture, are described. The possibilities neutron neutron detection and spectrometry are also described. The following experiment deals with a design of suitable shielding materials and the analysis of the moderated energy spectrum of neutron flux. The properties of the neutron field were measured using detection by activation. Subsequently, a simulation of the problem was performer in the MCNP program. In the end, the achieved results are compared and evaluated.
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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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Determination of photon dose equivalent rate by means of field multichannel gamma-ray spectrometers GS-256 and GR-320, and by radiation detector Gamma-Scout.
Mokrá, Zuzana ; Matolín, Milan (advisor) ; Chalupa, František (referee)
Práce se zabývá porovnáním dvou terénních geofyzikálních přístrojů na měření záření s radiologickým přístrojem. Vrámci řešení úkolu proběhly měření radioaktivity na geologických lokalitách s nízkou, střední a vysokou radioaktivitou přenosnými mnohokanálovými gama spektrometry se scintilačními detektory NaI(Tl) 76x76 mm a pomocí přístroje Gamma-Scout s malým Geiger-Müllerovým počítačem. Jednotlivými přístroji byly stanoveny hodnoty v jednotkách příkonu fotonového dávkového ekvivalentu (Sv/h) a ty pak srovnány. Byly očekávány odchylky v naměřených datech. Odchylky byly různé pro rozdílné způsoby výpočtu přikonu fotonového dávkového ekvivalentu z naměřených dat. Z terénních výsledků vyplývá, že výsledky jednotlivých přístrojů lze porovnávat, přičemž rozdíly jsou zapříčiněny různou detekční účinností a různou kalibrací jednotlivých přístrojů.
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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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Gamma and X- ray CdTe/CdZnTe detectors
Pekárek, Jakub
In the present work we studied an influence of different types of surface etching and surface passivation of high resistivity CdZnTe-based semiconductor detector material. The aim was to find the optimal conditions to improve the properties of metal-semiconductor contact. The main effort was to reduce the leakage current and thus get better X-ray and gamma-ray spectrum, ie to create a detector operating at room temperature based on this semiconductor material with sufficient energy resolution and the maximum charge collection efficiency. Individual surface treatments were characterized by volt-ampere characteristics, spectral analysis and by determination of the profile of the internal electric field.
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Digital signal processing using field programmable gate arrays
Vykydal, Jan ; Kubíček, Michal (referee) ; Kolka, Zdeněk (advisor)
This thesis deals with the design, implementation and testing of an equipment that performs spectral analysis of a gamma radiation, based on the evaluation of pulses from a scintillation detector. The pulzes are pre-amplified and digitized, and their further processing takes place numerically in an FPGA, which allows a simple modification of the function of the developed device. After an introduction to the issue of gamma radiation spectroscopy with a focus on its detection, the thesis is devoted to the development of a multichannel analyzer hardware, whose individual parts are further described later. Next, the development of a digital signal processing system in the FPGA is described. Followed by an analysis of a microcontroller firmware, and a text protocol for the controlling of the device. Finally, the results of the work are discussed, with a focus on the test measurement of gamma radiation.
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