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Materials shielding properties measurement
Michal, Martin ; Burian, Jiří (referee) ; Katovský, Karel (advisor)
This thesis deals with the issue of ionizing radiation, specifically gamma radiation and its shielding. This radiation is produced, for example, during a fission reaction in a nuclear reactor. Materials such as lead, or concrete are most often used to shield gamma radiation. This is due to their low cost and high density. The task of new trends is to try to replace these existing materials with more efficient, lighter, and non-toxic materials. The aim of the practical part was the calculation of linear attenuation coefficients. For the calculation, the values of the thickness of the shielding sheets, the intensity of the unattenuated beam and the attenuated beam were needed. These values were determined from measurements. For more accurate calculations, the background value was also measured, which was then subtracted from the intensity values of the undamped beam. The resulting values were compared with each other.
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Composite materials with enhanced coefficient of linear attenuation of ionizing radiation
Novotný, Kamil ; Petruš, Josef (referee) ; Kučera, František (advisor)
Ionizing radiation has many useful applications in the fields of healthcare, food industry, nuclear energy and others but poses a hazard to human health in higher doses. In this work, composite materials with enhanced ionizing radiation attenuation properties were prepared. Unsaturated polyester resin was reinforced with inorganic fillers containing elements such as bismuth or barium. Morphology of the samples was studied using scanning electron microscopy. Theoretical values of mass attenuation coefficients were obtained for photon energies 662 keV and 1253 keV using the XCOM software. The attenuation of ionizing gamma radiation was experimentally measured using radioactive sources 137Cs and 60Co. Linear attenuation coefficients and half value layers of the materials were determined using the obtained data. Addition of the fillers improved the shielding properties of the matrix. Composite containing bismuth oxide achieved the highest values of linear and mass attenuation coefficients. The experimental results were found to be in good agreement with theoretical values. Moreover, influence of the fillers on impact toughness has been evaluated.
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