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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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Gamma Radiation Measurement
Lázna, Tomáš ; Jílek, Tomáš (referee) ; Žalud, Luděk (advisor)
This thesis is focused on detection of ionizing radiation, especially gamma radiation. In its theoretical part the issue is presented and the most common detector types (gas filled, scintillation and semiconductor detectors) are analysed. In its practical part the parameters of the chosen sensor HDS-100GN are verified with a focus on its capability of dynamical measurement. The robot Orpheus-X3 equipped with the precise RTK-GNSS receiver was used in the realization of the experiment. The analysis of the measurement results furthermore covers conversion of geographical coordinates to distance, determination of latency, conversion of measured value to dose rate and comparison with theoretical assumptions were solved. Formation of an area radiation map is also concerned. Direction-sensitive detection of gamma radiation is also studied in this thesis.
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Corosion changes ultra-thinwalled capillary
Solný, Tomáš ; Zmrzlý, Martin (referee) ; Kotlík, Josef (advisor)
This thesis is focused on the technology of producing ultra-thin-walled capillaries. The summary of physical and chemical properties affecting corrosivity of produced capillaries is done. The explanation of defects in glass structure of capillaries is done focusing to defects formed by the gamma radiation impacts on their structure. Short experimental part deals with the improvement of glass surface due to chemical polishing by hydrofluoric acid.
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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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Optical fibre dosimeter
Jelínek, Michal ; Mikel, Břetislav
In the nuclear facility, there is currently a demand for optical methods of measuring gamma radiation. For these measurements, we need very robust measurement methods and sophisticated equipment. Silica optical fibres coupled to crystal scintillators are suitable and we present results from their implementation. The scintillators detect gamma radiation and the silica optical fibres transmit the scintillation light from the scintillator to the detector. We used commercially available silica optical fibres up to 1.5 mm in diameter with different numerical apertures to transmit visible light from the scintillators to the detector.
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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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Structural Analysis Of Gaas-Based Pv Cells After Ionizing Irradiation
Papež, Nikola
Morphology and structural analysis of photovoltaic cells based on GaAs before and after high dose gamma radiation of 500 kGy was investigated. Cobalt-60 emitter was used as the synthetic radioactive isotope. This radioactive form of cobalt is commonly used for space instruments and devices testing. Atomic force microscopy (AFM) was used to study the morphology and roughness differences. Cross-sectional investigation using transmission detector to thin layers observing was performed. Also, with use of sputtering system of Secondary Ion Mass Spectroscopy (SIMS) a detailed molecular and elemental information about the surface top layers was showed. Another molecular and structural changes in the top layers using two optical methods of Raman spectroscopy and spectrophotometry were also identified.
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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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