Browsing by Author "Fornal, Bogdan"
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Item Badanie struktury jąder neutrononadmiarowych wzbudzanych w reakcjach głęboko nieelastycznego rozpraszania ciężkich jonów(Institute of Nuclear Physics Polish Academy of Sciences, 2004) Fornal, BogdanA new experimental method, exploiting the analysis of gamma-gamma coincidences measured with large germanium multidetector arrays in deep-inelastic heavy ion collisions, has been used to extend the in-beam gamma-ray spectroscopic studies towards previously inaccessible neutron-rich nuclei. In particular, the neutron-rich Ti isotopes have been accessed using deepinelastic processes occurring during the bombardments of a thick 208Pb target with a 305-MeV 48Ca beam. Yrast structures in 53Ti and 54Ti nuclei have been identified for the first time using cross coincidences with known gamma rays from complementary mercury products. Also, spectroscopic information has been extended for 52Ti. The experimental findings have been compared with shell model calculations performed in the full fp shell with the FPD6 and GXPF1 effective interactions. The results fully confirm the existence of a subshell closure at N=32 in Ti neutron-rich isotopes. This new subshell closure has been attributed to a decreased pf7/2 - nf5/2 monopole interaction as protons are removed from the pf7/2 orbital: the migration of the nf5/2 orbital to higher energies with the removal of protons from the f7/2 orbital, in combination with the large spin-orbit splitting for np3/2-np1/2, gives rise to an energy gap at N=32 for nuclides having Z≤24. Data from the same reaction 48Ca+208Pb provided also new spectroscopic information on 208Bi and 210Bi nuclei. Yrast and near-yrast levels up to ~5.6 MeV in 208Bi and up to 4.6 MeV in 210Bi have been located - they are interpreted in light of earlier charged particle spectroscopy results, and with the help of shell model calculations in a large configuration space extending from 132Sn to 310 126X184. Another hard-to-reach nucleus, 206Hg, was accessed using 208Pb(1360 MeV)+238U collisions. The yrast states found include a T1/2=92(8) ns 10+ isomer located above the known 5- isomer. The B(E2;10+→8+) reduced transition probability was used to derive the quadrupole polarization charge epol=0.60(7)e induced by the h11/2 proton hole on the doubly magic 208Pb core. Comparison of epol(ph11/2 -1) with the quadrupole polarization charges known for other high spin orbitals has revealed the constancy of the polarization charges induced by high j protons or neutrons on doubly magic cores. Theoretical considerations, based on the coupling between vibrational degrees of freedom and those of the single particles, reproduce the main features of experimental data regarding epol.Item Profesor Henryk Niewodniczański i jego niespożyta pasja,fizyka jądrowa(2018) Fornal, BogdanZ okazji 50. rocznicy śmierci Założyciela i Patrona Instytutu Fizyki Jądrowej, prof. Henryka Niewodniczańskiego, zorganizowano uroczyste seminarium, podczas którego wygłoszono referaty poświęcone tematyce naukowej uprawianej przez prof. Niewodniczańskiego. Referat poświęcony fizyce jądrowej wygłosił prof. dr hab Bogdan Fornal.Item Report on Research Activities 2017-2020(Institute of Nuclear Physics Polish Academy of Sciences, 2021-05) Maj, Adam; Fornal, Bogdan; Grębosz, Jerzy; Horzela, Andrzej; Kopeć, Renata; Kwiatek, Wojciech; Lesiak, Tadeusz; Olko, Paweł; Skrzypek, Maciej; Świerblewska, Iwona; Świerblewski, Jacek; Wilczyński, Henryk; Zieliński, PiotrThe "Report on Research Activities 2017-2020" summarizes the most important highlights of the scientific activities at IFJ PAN in the last four years. These highlights encompass activities in both fundamental and application research. Studies concerning basic research were carried out at the Division of Particle Physics and Astrophysics, the Division of Nuclear Physics and Strong Interactions, the Division of Condensed Matter Physics and at the Division of Theoretical Physics. In turn, the works related to scientific applications were conducted at the Division of Interdisciplinary Research and the Division of Applications of Physics. Of particular importance is the Cyclotron Centre Bronowice (CCB), which is a spectacular demonstration of the strong connection between basic research and applications. Reported is also information about the Krakow School of Interdisciplinary PhD Studies (KISD) which is coordinated by IFJ PAN, about the division of the construction of scientific equipment and infrastructure (DAI), about accredited laboratories, as well as about the outreach activity which has been carried out with great vigor. We invite the Reader of the Report to learn about all of the main research achievements of our Institute in recent years.Item Structure of Bi isotopes close to the 208Pb doubly-magic core(Institute of Nuclear Physics Polish Academy of Sciences, 2014) Cieplicka, Natalia; Fornal, Bogdan; Maj, Adam; Pfützner, MarekThe atomic nucleus, being a dense system of protons and neutrons, can be considered as a 'laboratory' in which three fundamental interactions strong, electromagnetic and weak, can be studied. Although much experimental data concerning the structure and characteristics of the atomic nucleus have been collected, a theoretical description which would explain all the observed phenomena is still incomplete. This is in part because the nucleon-nucleon interaction has very complex characteristics due to the fact that nucleons are not fundamental particles so they have an intrinsic structure (thus, the description of nuclear forces must take into account that nucleon-nucleon interactions are the result of interactions between the quarks). It is also because the nucleus, as a system of many strongly interacting nucleons obeying the Pauli exclusion principle, demonstrates a very high degree of complexity. Moreover, electromagnetic and weak interactions manifesting in the atomic nucleus are the source of additional complications in its description. As a consequence, progress in theory must go together with experimental investigations, which results in a strong connection between theory and experiment in nuclear physics. New theoretical concepts dictate which experiments would be the most effective in verifcation of a particular model. On the other hand, measurements can inspire theory to gain better parameter values from its models. To describe the atomic nucleus as a system of more elementary constituents (nucleons), one needs to know the wave function being the solution of wave equation for such a system. Due to the diffculties mentioned above, one needs to use simplifed models instead of the exact description. One of them is the shell model, which explains many experimental observations, such as magic numbers of nucleons: 2, 8, 20, 28, 50, 82, 126, the spin-parity values of the ground states of many nuclei, as well as the structure of excitations of nuclei in the region of magic nuclides. While the shell model with a classic set of orbitals works well near doublymagic nuclei lying close to the stability valley, in the exotic regions of the nuclear chart; i.e., in the regions remote from stability, the situation is different - the structure of singleparticle energy levels changes and new energy gaps may show up while the classical ones may disappear.One way to trace all these changes, is to undertake systematic investigations of excited structures along a chain of neutron-rich isotopes to the description of which the shell model can be applied. In the present work, we have chosen as the objective of study the series of Bi isotopes near the doubly-closed nucleus 208Pb. We have investigated the 205;206;210Bi nuclei, which have one valence proton and from four neutron holes to one neutron particle with respect to the doubly-magic core 208Pb. Since 208Pb is considered to be one of the best doubly-closed cores due to remarkably wide energy gaps which separate proton shells at Z=82 and neutron shells at N=126, the structure of the 205;206;210Bi nuclei is an excellent testing ground for modern shell-model calculations. In the present work, information about the high-spin yrast structures in the 205;206;210Bi isotopes has been extended. In particular, the aim of the work is the identifcation of high spin states arising from valence particles/holes excitations and from core excitations in 205;206;210Bi. Also, the spectroscopic data on the low-spin excitations in 210Bi were acquired in a neutron-capture reaction. The neutron rich nuclei are diffcult to reach for spectroscopy studies, because they cannot be produced in fusion-evaporation reactions. The access to excited structures at high spin in those nuclides is possible thanks to a method which relies on using deep-inelastic collisions (DIC) of heavy ions - this method has been developed at IFJ PAN. The main object of interest in the presented thesis are high-spin structures in Bi isotopes. The experiments aimed at investigating those structures were performed at Argonne National Laboratory, where Bi nuclei were populated in deep-inelastic reactions with the use of 76Ge and 208Pb beams on 208Pb target. During such reactions, the nuclei come to a close contact and much kinetic energy is dissipated giving rise to internal excitation energy. In the exit channel one has then two products excited to relatively high energy and spin. Since thick targets were used, the products were stopped inside the target and most of the rays that were measured with the use of the Gammasphere multidetector germanium array, appeared in the spectra as sharp lines - they were emitted from nuclei at rest. The second experiment, performed at the Institute Laue-Langevin in Grenoble, was devoted to the low-spin structure of the 210Bi nucleus. In this case 210Bi was produced in cold-neutron capture on 209Bi. The spectroscopic measurements in the non-yrast low-energy region of 210Bi could be performed. In the first chapter, an introduction to the structure of the atomic nucleus is presented - it includes: the characteristics of nuclear forces and the foundations of the shell model as well as the calculation methods and computer codes used nowadays. The second chapter provides a short description of the region of interest - the region around doubly-magic 208Pb - with emphasis on Bi isotopes. The third chapter presents description of the reactions leading to the nuclei of interest, the experiments which were performed, and the methods of analysis of the coincidence and angular distributions and correlations of -ray data. In the fourth chapter, the experimental results are discussed. The fifth chapter is devoted to comparisons of the experimental results with predictions based on shell-model calculations involving the presently available two-body shell-model interactions. The last part contains a summary.Item 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".
