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Localization Of Gamma Radiation Sources
Lazna, Tomas
The paper describes a method for acquiring and processing data concerned with a radiation situation in a pre-defined region of interest with a goal of localizing point sources present in the region. The acquisition underlies the robotic platform Orpheus-X4 equipped with a precise navigation module and gamma radiation detectors, a path planning involves Boustrophedon decomposition. The processing is based on the Gauss-Newton method, a contribution of the paper consists in a way to provide the method correct input data. Introduced algorithms were verified experimentally. Although not all sources can be found using the chosen equipment, in case of successful localization the accuracy is not worse than 0.1 m.
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Dose analysis of the MAPE Mydlovary staff
RŮŽIČKOVÁ, Eliška
In the previous century a uranium ore chemical processing plant was constructed about 20 km from České Budějovice called MAPE Mydlovary, which employed approximately 1,100 employees at various times. We can assume that radionuclides affected the company's employees during the processing of uranium ore and the subsequent storage of waste in the adjoining sludge lagoons. They were irradiated by a total of three radiation components, which included gamma radiation, short-lived radon decay products and long-lived radionuclides from the uranium decay chain emitting alpha radiation. This is why this bachelor's thesis is devoted to analysis and evaluation of the percentage of individual radiation components in the total dose received by former MAPE Mydlovary employees. The purpose of this work is to establish how the individual radiation components were distributed in the doses of radiation received by former employees. The dosimetric sheets of former MAPE Mydlovary employees, who received all three types of radiation, were analysed in order to answer the research question. Dosimetric sheets were reduced so that each sheet contained all the required information. The established average annual doses of all three types of radiation and the total effective doses were converted into a graph, evaluated and subsequently compared with the valid legislation. On the basis of evaluation of the acquired data we can state that long-lived radionuclides from the uranium decay chain emitting alpha radiation made up the highest percentage of the radiation doses received by former MAPE Mydlovary employees, at a total of 49%. Inhalation of short-lived radon decay products made up 29% and external gamma radiation just 22%. The radiation limit for radiation workers of 20 mSv/year on the total effective dose from exterior radiation and on the committed effective doses from internal radiation was exceeded by 8 former employees according to our current legislation. We must state that no rules were broken according to Czech legislation valid between 1960 and 1970, because the limit for radiation workers was set at 50 mSv/year.
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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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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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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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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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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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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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