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Ionizing radiation behavior and shielding
Konček, Róbert ; Štefánik, Milan (oponent) ; Katovský, Karel (vedoucí práce)
Ionizing radiation is radiation with particle energies greater than the energy needed to remove an outermost electron from an atom. Exposure to ionizing radiation causes damage to living tissue, and can result in detrimental mutations. Thus, ionizing radiation shielding is discipline of great practical importance. This thesis is concerned with its basic principles and methods. Firstly, it gives thorough account of four major classes of ionizing radiation - alpha and beta particles, gamma rays, and neutron radiation - and their peculiarities with respect to shielding. The next part contains description of mathematical model developed to assess and simulate interactions of radiation with matter. Finally, assignment for a laboratory exercise is presented.
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Využití nanotechnologií v jaderné energetice
Skalička, Jiří ; Štefánik, Milan (oponent) ; Katovský, Karel (vedoucí práce)
Práce shrnuje současné poznatky o nanomateriálech a jejich použití. Zabývá se hlavně metodami výroby a použitím jednotlivých typů materiálů v oblasti jaderné energetiky, jaderného výzkumu a jaderné medicíny. Teoretická část je věnována možnostem využití uhlíkových nanotrubek pro kolimaci nebo vedení svazku neutronů. V experimentální části bylo zjišťováno, jak vybrané nanomateriály ovlivňují neutronový tok v měřícím boxu napojeném na horizontální radiální kanál reaktoru VR-1. Otestovány byly neorientované uhlíkové nanotrubky, uhlíková nanovlákna, nanodráty z aluminy, orientované uhlíkové nanotrubky při různém natočení a výsledky byly porovnány s výsledky při použití grafitu.
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Spectrometry of neutron field based on p(20)+Be source reaction
Kozic, Ján ; Štefánik, Milan
The research deals with a spectrometry of neutron field based on the p(20)+Be source reaction. The p(20)+Be interaction stands for a nuclear reaction where protons accelerated to energy of 20 MeV bombard Be target. Produced neutron field has broad energy distribution up to 18 MeV. The research was carried out at the Nuclear Physics Institute of the Czech Academy of Sciences and was motivated by extension of experimental possibilities of the NG-2 target station. To determine the neutron spectrum, the activation foil technique was used. During the experiment, ten activation foils were irradiated. Activated foils were measured using the HPGe detector to determine the reaction rates of observed reactions. The neutron field was simulated in the MCNPX code, and the simulation served as a priori information for the unfolding of the neutron spectrum in the SAND-II code. A determined neutron spectrum is essential for various experiments, e.g., material research, measurements of nuclear data, etc.
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Spectral flux of the p-Li-7(C) Q-M neutron source measured by proton recoil telescope
Novák, Jan ; Bém, Pavel ; Fischer, U. ; Götz, Miloslav ; Honusek, Milan ; Simakov, S. P. ; Šimečková, Eva ; Štefánik, Milan
The cyclotron-based fast neutron source at NPI produces mono-energetic neutron fields up to 35 MeV neutron energy using the p + 7Li(carbon backing) reactions. To be applied for activation cross-section measurements, not only the intensity of neutron peak, but also the contribution of low-energy continuum in the spectra must be well determined. Simulations of the spectral flux from present source at a position of irradiated samples were performed using CYRIC TOF-data validated in the present work against LA150h by calculations with the transport Monte Carlo code MCNPX.
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The activation of W and Zr by deuterons at energies up to 20 MeV
Šimečková, Eva ; Štefánik, Milan ; Bém, Pavel ; Mrázek, Jaromír ; Novák, Jan
The proton and deuteron induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, target and beam stoppers. In order to investigate the important nuclides, we have carried up the irradiation experiments with the variable-energy cyclotron U-120 M of the NPI CAS ež. The production cross sections of the nuclides 179,181,182m,182,183,184m,184,186Re and 187W from reaction on natural W were investigated by deuteron beams of 20 MeV energy. A part of preliminary results of deuteron activation of natural Zr is also shown. The stacked-foil technique was utilized. The comparison of present results to data of other authors and to predictions of evaluated data libraries is discussed.
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Proton and deuteron activation measurements at the NPI and future plans in SPIRAL2/NFS
Šimečková, Eva ; Bém, Pavel ; Mrázek, Jaromír ; Štefánik, Milan ; Běhal, Radomír ; Glagolev, Vadim
The proton- and deuteron-induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, target and beam stoppers as well as isotope production for medicine. In the present work, the deuteron-induced reaction cross sections on zinc were investigated by stacked-foil activation technique with deuteron beam of 20 MeV energy from the cyclotron U-120M of NPI CAS ež. Also the proton activation cross section measurement of iron is presented. The comparison of present results to data of other authors and to predictions of evaluated data libraries is discussed. The investigation shall continue for higher proton and deuteron energy interval 20-35 MeV at SPIRAL2/NFS facility using a charged particle irradiation chamber with pneumatic transport system to measure isotopes and isomers with half-lives in minutes-regions.
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Ionizing radiation behavior and shielding
Konček, Róbert ; Štefánik, Milan (oponent) ; Katovský, Karel (vedoucí práce)
Ionizing radiation is radiation with particle energies greater than the energy needed to remove an outermost electron from an atom. Exposure to ionizing radiation causes damage to living tissue, and can result in detrimental mutations. Thus, ionizing radiation shielding is discipline of great practical importance. This thesis is concerned with its basic principles and methods. Firstly, it gives thorough account of four major classes of ionizing radiation - alpha and beta particles, gamma rays, and neutron radiation - and their peculiarities with respect to shielding. The next part contains description of mathematical model developed to assess and simulate interactions of radiation with matter. Finally, assignment for a laboratory exercise is presented.
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Využití nanotechnologií v jaderné energetice
Skalička, Jiří ; Štefánik, Milan (oponent) ; Katovský, Karel (vedoucí práce)
Práce shrnuje současné poznatky o nanomateriálech a jejich použití. Zabývá se hlavně metodami výroby a použitím jednotlivých typů materiálů v oblasti jaderné energetiky, jaderného výzkumu a jaderné medicíny. Teoretická část je věnována možnostem využití uhlíkových nanotrubek pro kolimaci nebo vedení svazku neutronů. V experimentální části bylo zjišťováno, jak vybrané nanomateriály ovlivňují neutronový tok v měřícím boxu napojeném na horizontální radiální kanál reaktoru VR-1. Otestovány byly neorientované uhlíkové nanotrubky, uhlíková nanovlákna, nanodráty z aluminy, orientované uhlíkové nanotrubky při různém natočení a výsledky byly porovnány s výsledky při použití grafitu.
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