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Browsing by Author "Stachura, Zbigniew"

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    Development of Kraków External Microbeam - Single Ion Hit Facility
    (Institute of Nuclear Physics Polish Academy of Sciences, 2004) Polak, Wojciech; Hajduk, Roman; Lebed, Sergey; Lekki, Janusz; Horwacik, Tomasz; Maranda, Stanisław; Pieprzyca, Tomasz; Sarnecki, C.; Stachura, Zbigniew; Szklarz, Zbigniew; Veselov, O.; Styczeń, Jan
    The main purpose of building the microbeam setup for the external (i.e out-of-vacuum) measurements is single cell with single ions irradiation. The single-ion hit facility is based on the existing Kraków microbeam setup characterized by the spatial resolutions of about 3 μm. Present work introduces the setup and the measurement chamber that was developed, constructed and assembled in IFJ PAN. The passage of single ions from vacuum to atmosphere (where the cell dish is located) is registered using the channeltron detector installed inside the chamber. Channeltron registers secondary electrons emitted from CsI layer covering the Si3N4 exit window. The system of very precise diaphragms reduces the beam intensity down to a fluence of about 103 protons/sec. The beam blanking, correlated with single proton passage is provided by the fast, electrostatic deflecting system. The precise 3D table, installed outside the chamber, allows positioning the cell dish at a 200 μm distance from the exit window and change the targeted cell with a sub-micrometer precision within the dish. The paper shows results of the preliminary investigations aimed towards optimization of the most important issues: resolution of external microbeam, proton registration efficiency, efficiency of deflecting system and accuracy of single-proton-hit system.
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    Development of the IFJ Single Ion Hit facility for cells ir r adiation
    (Institute of Nuclear Physics Polish Academy of Sciences, 2005) Veselov, O.; Polak, Wojciech; Ugenskiene, R.; Hajduk, Roman; Lebed, Kateryna; Lekki, Janusz; Horwacik, Tomasz; Dutkiewicz, Erazm; Maranda, Stanisław; Pieprzyca, Tomasz; Sarnecki, C.; Stachura, Zbigniew; Szklarz, Zbigniew; Styczeń, Jan
    In recent years a single ion hit facility (SIHF) has been constructed at the IFJ ion microprobe. The setup is used for the precise irradiations of living cells by a controlled number of ions. The facility allows investigations in various aspects of biomedical research, such as adaptive response, bystander effect, inverse dose-rate effect, low-dose hypersensitivity, etc. Those investigations have two very important requirements: (i) cells must be examined in their natural state and environment, i.e. without previously being killed, and preferentially, neither fixed nor stained, and (ii) a possibility of automatic irradiation of large number of cells with a computer recognition of their positions must be provided. This work presents some of the crucial features of the off-line and on-line optical systems, including self-developed software responsible for the automatic cell recognition. We also show several tests carried out to determine the efficiency of the whole setup and some segments. In conclusion, the results of our first irradiation measurements performed with living cells are demonstrated.
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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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    XANES and SR-XRF study of skin as a barrier to ultra-fine nanocrystals of TiO2
    (Institute of Nuclear Physics Polish Academy of Sciences, 2007) Kwiatek, Wojciech M.; Lekki, Janusz; Stachura, Zbigniew; Hanson, Albert L.; Ablett, James
    Nanocrystalline TiO2 is commonly used in cosmetic industry as a photoprotective agent. With recent advances in nanomaterial processing, the size of TiO2 crystals decreased into the nanometre regime. There is no satisfactory evidence that crystals of such small size are harmless to the human population. An EU project NANODERM has been launched where several techniques have been applied to investigate the possiblity of particle penetration through the protective horny layer into vital skin regions. Skin biopsies of the animal and human skin have been collected after exposition to formulations containing TiO2 nanocrystals. The Ti depth distributions were measured by electron and ion microscopy. The microscopy studies did not detect penetration into vital tissue of healthy skin what does not exclude a possibility that TiO2 could penetrate pathological skin with lowered barrier efficiency. Due to literature the physical effect of the UV irradiation of the TiO2 nanoparticle is the shift from 4th to 3rd oxidation state of the Ti. Titanium at 3rd oxidation state interact with environment producing free radicals and Reactive Oxygen Species. In order to quantify the oxidation state shift, XANES experiments were carried out with commercially available TiO2 nanocrystals (6–100 nm size), both in anatase and rutile phase. The samples were irradiated with X-rays with, and without accompanying UV illumination at the NSLS X27A beam line. The corresponding XANES spectra were registered and the absorption edge was compared in UV–illuminated and not illuminated spectra. A shift of about 1 eV in the absorption edge position of the rutile sample exposed to UVA light (365 nm, 20 mW/cm2) has been measured and attributed to the changed electron configuraion. However, the direction of the shift detected in measured samples was opposite to the expected.