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Browsing by Author "Bielecki, Jakub"

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    Assumptions for the design of a neutron pinhole camera dedicated to the PF-24 device
    (Institute of Nuclear Physics Polish Academy of Sciences, 2014) Scholz, Marek; Bielecki, Jakub; Wójcik-Gargula, Anna; Wiącek, Urszula; Drozdowicz, Krzysztof; Igielski, Andrzej; Kulińska, Agnieszka; Tracz, Grzegorz; Woźnicka, Urszula
    The report presents main assumptions on the design of the neutron pinhole camera dedicated to the PF-24 (Plasma Focus) device. The pinhole camera will be used for the investigation of the spatial and temporal distributions of DD neutrons from the PF-24 source. It makes use of principles of the optical geometry adopted for neutron imaging. In the report the evaluation of pinhole geometrical layout has been made on the basis of principles of the geometrical optics. A further optimization of the pinhole geometry has been carried out by means of neutron transport calculations (the MCNP code). The main aim of this report is to provide information on technical solutions for the neutron pinhole.
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    From Classical to Plasma Tomography
    (Institute of Nuclear Physics Polish Academy of Sciences, 2018) Bielecki, Jakub
    This monograph is an attempt at a comprehensive treatment of tomographic reconstruction methods with the special emphasis on the application in fusion research. Therefore, the main volume of the book is devoted to tomographic inversion methods that are either commonly used in the fusion research or they have just been developed and published by me or other researchers. However, detailed explanation and discussion of plasma tomography principles would not have been possible without giving an introduction to classical tomographic reconstruction methods. By these classical methods, I mean here analytical and algebraic methods commonly applied not only in medicine but also in many different fields such as geophysics, bioscience or material science. Inversion methods applied in plasma tomography significantly differ from classical ones. This is mostly due to the nature of the data collected in tomographic experiments carried out with fusion devices. The algebraic reconstruction method, shortly described in Chapter 5, can be considered as a link between classical tomographic methods described in the preceding part of the book and reconstruction methods that are specific to fusion research. In fact, most of the reconstruction methods used in fusion science belong indeed to the class of algebraic methods. However, due to the fact that measured data sets are sparse and the reconstruction problem is strongly ill-posed, specific methods that include a regularisation are required. This is shown and discussed in Chapter 6. My main motivation in publishing this work was a desire to share, with the widest possible readership, a comprehensive monograph on plasma tomography. I would expect the target audience to be primarily academics, with a special emphasis on graduate and PhD students from plasma physics and fusion research community. I hope that this book can serve as a self-contained resource for PhD students wishing to extend their knowledge on plasma tomography. I tried to present as many practical applications as possible, focusing mostly on the recent advances made with tokamak devices. I assume the Reader is familiar with the basic concepts of plasma physics and thermonuclear fusion, as well as with basic mathematical apparatus such as linear algebra. The introductory chapters and proofs of presented theorems should help the Reader to immerse into the ideas presented through the book. For the sake of clarity, some detailed information and additional proofs are postponed to the appendices.
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    Linia eksperymentalna do napromieniania pojedynczych żywych komórek przy stanowisku mikrowiązki rentgenowskiej w IFJ PAN. Opis techniczny
    (Institute of Nuclear Physics Polish Academy of Sciences, 2011) Bożek, Sebastian; Bielecki, Jakub; Stachura, Zbigniew; Lekki, Janusz; Sienkiewicz, Michał; Świerblewski, Jacek; Pieprzyca, Tomasz; Szklarz, Zbigniew; Dutkiewicz, Erazm; Hrynkiewicz, Andrzej; Kwiatek, Wojciech M.
    X-ray experimental microbeam line for single live cells irradiation has been constructed at the Institute of Nuclear Physics PAN. The facility is based on an open type X-ray tube with microfocusing (the X-ray emission spot size is about 2 micrometers in diameter) and anode exchange ability. In the microdosimetry experiment a Titanium anode with the 4.5 keV energy of Ka characteristic radiation line is used. The X-ray radiation, emitted from the spot into a cone of 120 degrees angle, is focused on the sample using the X-ray focusing multilayer mirrors in the Montel geometry. The focusing distance is 32 mm, and the focal spot is about 20 micrometers in diameter. The beam image can be observed using the X-ray sensitive CCD camera, as well as with the use of an optical microscope and the P43 scintillator screen. Cells are seeded on a thin mylar foil, which is mounted on a drilled opening in the bottom of the Petri dish. After visual selection of cells dedicated to irradiate, and setting of experimental parameters, the irradiation process is carried out automatically, and cells are irradiated with a controlled X-ray dose.
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    Metoda mikrotomografii komputerowej dla układu mikrowiązki promieniowania X w zastosowaniu do wyznaczania porowatości i powierzchni właściwej skał
    (Institute of Nuclear Physics Polish Academy of Sciences, 2009) Bielecki, Jakub; Bożek, Sebastian; Lekki, Janusz; Stachura, Zbigniew; Jarzyna, Jadwiga; Kwiatek, Wojciech M.
    Celem pracy było opracowanie metodyki pomiarów wybranych własności fizycznych próbek geologicznych metodą mikrotomografii komputerowej. Badania zostały wykonane w Instytucie Fizyki Jądrowej PAN z wykorzystaniem układu mikrowiązki promieniowania X przy współpracy z Katedrą Geofizyki WGGiOŚ Akademii Górniczo-Hutniczej w Krakowie. Przedstawione zostały wstępne wyniki pomiarów porowatości i powierzchni właściwej przestrzeni porowych dla próbki skały piaskowca wydobytego z otworu CG5 na głębokości 2680 m. Omówiona została metoda segmentacji obrazów tomograficznych oraz algorytmy cyfrowej analizy danych tomograficznych. Praca przedstawia możliwości zastosowania metody mikrotomogarfii komputerowej o wysokiej przestrzennej zdolności rozdzielczej w połączeniu z metodami cyfrowej analizy danych do badania materiałów porowatych.
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    Multipurpose X-ray microprobe in the IFJ PAN. Technical description
    (Institute of Nuclear Physics Polish Academy of Sciences, 2009) Bielecki, Jakub; Bożek, Sebastian; Banaś, Agnieszka; Baszak, Jarosław; Doruch, Henryk; Hajduk, Roman; Kowalska, Joanna; Pieprzyca, Tomasz; Szklarz, Zbigniew; Lekki, Janusz; Stachura, Zbigniew; Kwiatek, Wojciech M.
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    Opracowanie algorytmów do analizy zdjęć z mikroskopii fluorescencyjnej
    (Institute of Nuclear Physics Polish Academy of Sciences, 2017-02) Tkocz, Konrad; Bożek, Sebastian; Bielecki, Jakub; Lekki, Janusz; Kwiatek, Wojciech M.
    The fluorescence microscopy is one of the fastest techniques of DNA damage visualisation induced by physical or chemical factors. For this reason, the area of algorithms for images analysis from fluorescence microscopy continually develops. This report contains presentation of algorithms elaborated for the assessment of relative amount of DNA damage, visualised with the fluorescent dyes Alexa Fluor 488 and DAPI. Methods of the determination of the noise level and signal to noise ratio in the images, as well as methods of noise reduction and image quality optimization have been presented.
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    Study of the mutual dependence between Lower Hybrid current drive and heavy impurity transport in tokamak plasmas. Part 1. Preparatory work and theoretical background
    (Institute of Nuclear Physics Polish Academy of Sciences, 2020) Jardin, Axel; Bielecki, Jakub; Król, Krzysztof; Peysson, Y.; Mazon, D.; Dworak, Dominik; Scholz, Marek
    This document reports the activities performed during the year 2019-2020 in the framework of the HARMONIA 10 project entitled “Study of the mutual dependence between Lower Hybrid current drive and heavy impurity transport in tokamak plasmas” as well as the preliminary results obtained during the first year of project execution. The project is founded by the Polish National Science Centre (NCN) and carried out in a close collaboration with the foreign partner - Institute for Magnetic Fusion Research (IRFM) of the French Alternative Energies and Atomic Energy Commission (CEA).
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    Using X-ray measurements to assess uncertainties in plasma temperature and impurity profiles in tokamaks
    (49th European Physical Society (EPS) Conference on Plasma Physics, 2023-07) Jardin, Axel; Krzysztof, Król; Mazon, Didier; Bielecki, Jakub; Dworak, Dominik; Guibert, Denis; Peysson, Yves; Scholz, Marek; Walkowiak, Jędrzej
    In tokamaks, the local X-ray plasma emissivity is a complex quantity resulting from the contribution of several plasma parameters, i.e. electron temperature, density and concentration of impurities in multiple ionization states. In particular, the impurity core concentration can be estimated from the emissivity in the soft X-ray (SXR) range 0.1 – 20 keV, while information about the superthermal electron population can be obtained in the hard X-ray (HXR) range 20 keV – 200 keV. The estimation of the tungsten concentration profile is subject to many uncertainties, in particular it requires accurate knowledge of plasma temperature, magnetic equilibrium, atomic processes leading to its cooling factor and the spectral response of the diagnostic. A global W concentration can, for example, be inferred with integrated simulation codes in order to match the total radiated power. When all other plasma parameters are well-known, the impurity density profile can be reconstructed in the core with the help of SXR tomographic tools. Nevertheless, in the case of a significant fraction of superthermal electrons e.g. due to RF heating, accurate estimation of electron temperature from ECE measurements can become a challenging task. Therefore, the goal of this contribution is to establish a methodology to assess the uncertainty in the core electron temperature and impurity concentration profiles based on X-ray measurements. The proposed strategy is to define a grid of candidates (Te, cW) scenarios and identify the ones having the highest consistency with respect to multiple line-integrated measurements. In order to determine the capabilities and limitations of such an approach, the method is first tested on well-known synthetic profiles in an arbitrary tokamak geometry. In a second step, first experimental tests are presented for some selected WEST discharges.