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Browsing by Author "Bednarczyk, Piotr"

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    Study of the Pygmy Dipole Resonances Using High - Resolution Gamma Spectrometers
    (Institute of Nuclear Physics Polish Academy of Sciences, 2016) Krzysiek, Mateusz; Bednarczyk, Piotr; Kulessa, Reinhard; Rusek, Krzysztof
    The excitation spectrum of atomic nucleus is, at high energies, dominated by the Giant Dipole Resonance (GDR), which is a collective oscillation of almost all neutrons vs.protons. Around neutron separation energy, well below the GDR, the presence of low-lying dipole strength have been reported in many nuclei and associated to so called Pygmy Dipole Resonance (PDR). In most simple picture it is interpreted as an oscillation of the excess neutrons forming the neutron-skin versus isospin saturated core of the nucleus. Many microscopic calculations have shown the relationship between the PDR strength and the neutron-skin thickness, which is determined by the symmetry energy of the equation of state (EOS). Furthermore, it was found that the PDR contribution to the cross-section of radiative neutron capture process is significant. Therefore, studies on PDR nature are attracting a lot of attention in recent years. So far the experimental evidence of PDR was based on scattering of real photons (γ,γ’), inelastic scattering of electrons, protons and alpha particles, and on relativistic Coulomb excitations. In the present thesis, for the first time the inelastic scattering of heavy ions, combined with high-resolution gamma spectroscopy, was conducted.General aim of the study, which is a subject of this thesis, was to investigate the properties of the dipole states in 140Ce nucleus around particle threshold where the pygmy dipole states are expected to appear. Of particular interest was the possible isospin mixing observed in previous (γ,γ’) and (α,α’γ) experiments. The more specific goal was to confront the experimental data with theoretical calculations using Distorted Wave Born Approximation (DWBA) based on a form factor obtained by folding the microscopically calculated transition densities which was done for the first time in this type of experiments. The experiment using the inelastic scattering of 17O at 20 MeV/u was performed in LNL-Legnaro in Italy. The scattered ions were detected by the two ΔE-E silicon telescopes of TRACE array in coincidence with the γ-rays emitted by the target nucleus. The gamma detection was done with a high energy resolutionusing the state-of-art AGATA array which is based on high-purity germanium (HPGe) detectors. To increase the detection efficiency in high energy region, nine large volume LaBr3:Ce scintillator detectors of HECTOR+ array were additionally applied.The results of the study allowed to confirm predominantly isoscalar character of the low-energy PDR states. For the first time, the fraction of isoscalar energy-weighted sum rule exhausted by the PDR and its strength was extracted for the 140Ce. Comparison with the predictions of the theoretical models allowed shedding some new light into the structure of the pygmy dipole states. Furthermore, obtained results will enrich still very limited database of experimental results, whatis necessary to gain complete knowledge of the PDR properties.
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    White Book on the Future of Low-Energy Nuclear Physics in Poland and the Development of the National Research Infrastructure
    (Środowiskowe Laboratorium Ciężkich Jonów, 2020) Maj, Adam; Rusek, Krzysztof; Bednarczyk, Piotr; Dudek, Jerzy; Fornal, Bogdan; Kicińska-Habior, Marta; Kistryn, Stanisław; Lewitowicz, Marek; Matulewicz, Tomasz; Nazarewicz, Witold; Satuła, Wojciech; Skalski, J.; Srebrny, Janusz; Stephan, E.; Trzaska, Władysław H.
    This Report presents the status and perspectives of low-energy nuclear physics research in Poland. It has become a tradition that the society of Polish nuclear physicists periodically summarizes the community's achievements and draws up plans for the future. The very first such reports was prepared by a team of scientists led by Professor Jerzy Jastrzębski and publisched by the Polish Nuclear Physisc Network under the title "Nuclear Physics in Poland 1996-2006". The next one, entitled "Long-Range Plan of Polish Nuclear Physics in the years 2007-2016" was prepared by the Commission of Nuclear Physics, the Advisory Board of the Narional Atomic Energy Agency of Poland. The team of editors was led by Professor Jan Styczeń. A few years latter, this Commission, led this time by Professor Krzysztof Rusek, published the "Long-Range Plan of Polish Nuclear Physics and Nuclear Methods, 2010-2020".
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    Zakopane Conference on Nuclear Physics Book of Abstracts
    (Institute of Nuclear Physics Polish Academy of Sciences, 2022) Bednarczyk, Piotr; Kmiecik, Maria; Matejska-Minda, Magdalena
    The Zakopane Conference on Nuclear Physics, for historical reasons called School, has been organized since 1963 by the Henryk Niewodniczanski Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) and the Marian Smoluchowski Institute of Physics of the Jagiellonian University. Over the years the School became a famous worldwide conference. Nowadays, the Zakopane Conference on Nuclear Physics has a character of a biennial international congress and is one of the major events in Poland, related to low-energy nuclear physics. During the construction of the scientific program special attention has always been paid to offering enthusiastic and pedagogical overviews of the most recent research subjects in nuclear physics from both theoretical and experimental points of view. Young participants have also the opportunity to present the results of their research in short talks or on posters. Currently, the conference theme is “Extremes of the Nuclear Landscape” and it is a forum for reviewing progress in theory and experiment at the forefront of nuclear research. This time special attention will be given to the structure of exotic, unstable nuclei. We will also focus on collective excitations of nuclear matter. Furthermore, the nuclear physics context of astrophysical processes will be widely discussed. An important part of the Conference will be devoted to presentations on the newest achievements in the nuclear structure and reactions investigations and their influence on other disciplines. Noticeable discoveries in these areas are closely linked to the ongoing development of experimental facilities and detectors, which is among the conference topics. The aim of the Conference is also to increase the mutual communication of physicists representing various areas of nuclear physics and to create opportunities for intense interaction between graduate students, young researchers, and senior scientists. The current 55th edition of the Zakopane Conference on Nuclear Physics is organized by IFJ PAN in cooperation with Coti Conference Time and is supported by NuPECC, CAEN, NAWA (The Polish National Agency For Academic Exchange).