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The "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., Monografia "Report on Research Activities 2017-2020" podsumowuje najważniejsze wydarzenia z działalności naukowej IFJ PAN w czterech ostatnich latach. Wydarzenia te były intensywnie rozwijane w badaniach podstawowych, jak i aplikacyjnych. Badania dotyczące badań podstawowych prowadzono w Oddziale Fizyki Cząstek i Astrofizyki, Oddziale Fizyki Jądrowej i Oddziaływań Silnych, Oddziale Fizyki Materii Skondensowanej oraz Oddziale Fizyki Teoretycznej. Z kolei prace związane z zastosowaniami naukowymi prowadzono w Oddziale Badań Interdyscyplinarnych oraz Oddziale Zastosowań Fizyki. Szczególne znaczenie ma Centrum Cyklotronowe Bronowice (CCB), które jest spektakularnym pokazem silnego związku między badaniami podstawowymi a zastosowaniami. W Raporcie podane są również informacje o Krakowskiej Interdyscyplinarnej Szkole Doktorskiej (KISD) koordynowanej przez IFJ PAN, o dziale budowy aparatury naukowej i infrastruktury (DAI), o laboratoriach akredytowanych, a także o prowadzonej z dużym rozmachem działalności popularyzującej badania naukowe. Zapraszamy Czytelnika Raportu do zapoznania się z najważniejszymi osiągnięciami badawczymi naszego Instytutu uzyskanymi w ostatnich latach.

A complete-spectroscopy investigation of low-lying, low-spin states in the one-proton-hole and one-neutron-hole nucleus $^{206}$Tl has been performed by using thermal neutron capture and γ-coincidence technique with the FIPPS Ge array at ILL Grenoble. The new experimental results, together with data for the one-proton-particle and one-neutron-particle nucleus $^{210}$Bi (taken from a previous study done at ILL in the EXILL campaign), allowed for an extensive comparison with predictions of shell-model calculations performed with realistic interactions. No phenomenological adjustments were introduced in the calculations. In $^{210}$Bi, state energies, transition multipolarities and decay branchings agree well with theory for the three well separated multiplets of states which dominate the low-lying excitations. On the contrary, in $^{206}$Tl significant discrepancies are observed: in the same energy region, six multiplets were identified, with a significant mixing among them being predicted, as a consequence of the smaller energy separation between the active orbitals. The discrepancies in $^{206}$Tl are attributed to the larger uncertainties in the determination of the off-diagonal matrix elements of the realistic shell-model interaction with respect to the calculated diagonal matrix elements, the only ones playing a major role in the case of $^{210}$Bi. The work points to the need of more advanced approaches in the construction of the realistic interactions.

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".

Aydın, Sezgin ( Aksaray, Yazar ), Background: The nuclear shape is a macroscopic feature of an atomic nucleus that is sensitive to the underlying nuclear structure in terms of collectivity and the interaction between nucleons. Therefore, the evolution of nuclear shapes has attracted many theoretical and experimental nuclear structure studies. The structure of the A≈70, N≈Z nuclei, lying far from the stability line, is interesting because a particularly strong proton-neutron correlation may occur here due to the occupation of the same orbits by nucleons of both types. In this region, different particle configurations drive a nucleus towards various deformed shapes: prolate, oblate, octupole, or nonaxial. These nuclear shapes change rapidly with nucleon number and also with angular momentum. This is reflected by a presence of different structures (bands) of excited states which exhibit a broad range of lifetimes. Purpose: The aim of this paper is to determine lifetimes of some high-spin excited states in As69 and Ge66 nuclei to examine the shape evolution in these neutron-deficient nuclei. Methods: Lifetimes of high-spin states in As69 and Ge66 have been measured by using the Doppler-shift attenuation technique with the GASP and recoil filter detector setup at the Laboratori Nazionali di Legnaro. The nuclei of interest were produced in the S32(95MeV)+0.8mg/cm2 Ca40 fusion-evaporation reaction. The strongest reaction channels 3p and α2p led to the As69 and Ge66 final nuclei, respectively. Using γ-γ-recoil coincidences we were able to determine very short lifetimes (in the femtosecond range) in the residual nuclei of interest. Results: In As69, the extracted lifetimes are τ=72 (-32, +45) fs for the 33/2+ state at 7897 keV and τ

https://journals.aps.org/prc/abstract/10.1103/PhysRevC.98.024324, Yrast and near-yrast levels up to an I = 17¯h spin value and a 6-MeV excitation energy have been delineated in the “two-neutron” 210Pb nucleus following deep-inelastic reactions involving 208Pb targets and a number of heavy-ion beams at energies ∼25% above the Coulomb barrier. The level scheme was established on the basis of multifold prompt and delayed coincidence relationships measured with the Gammasphere array. In addition to the previously known states, many new levels were identified. For most of the strongly populated states, spin-parity assignments are proposed on the basis of angular distributions. The reinvestigation of the ν(g9/2 )2, 8+ isomeric decay results in the firm identification of the low-energy E2 transitions involved in the 8+ → 6+ → 4+ cascade, and in a revised 6+ level half-life of 92(10) ns, nearly a factor of 2 longer than previously measured. Among the newly identified states figure spin I = 4–10¯h levels associated with the νg9/2i11/2 multiplet, as well as yrast states involving νg9/2j15/2, νi11/2j15/2, and ν(j15/2 )2 neutron couplings. The highest-spin excitations are understood as 1p-1h core excitations and the yrast population is found to be fragmented to the extent that levels of spin higher than I = 17¯h could not be reached. Four E3 transitions are present in the 210Pb yrast decay; three of these involve the g9/2 → j15/2 octupole component, as reflected in the 21(2) and >10 Weisskopf unit enhancements of the B(E3) rates of the first two. The fourth, 16+ → 13− E3 transition corresponds to the 3− core octupole excitation built on the νi11/2j15/2 state, in analogy to a similar E3 coupling to the νj15/2 level in 209Pb. Shell-model calculations performed for two-neutron states and 1p-1h 208Pb core excitations are in good agreement with the data. Evidence was found for the existence of a hitherto unknown high-spin β- decaying isomer in 210Tl. Shell-model calculations of the 210Tl levels suggest the possibility of a 11+ long-lived, β-decaying state, and the delayed yields observed in various reactions fit rather well with a 210Tl assignment.

Z 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.

Zakopane Conference on Nuclear Physics - Extremes of the Nuclear Landscape -- AUG 26-SEP 02, 2018 -- Zakopane, POLAND, WOS: 000463866500052, Recent ab initio calculations pointed out the importance of the three-body terms of the nuclear interaction, in the description of the structure of n-rich systems. The state lifetimes in light n-rich carbon and oxygen nuclei have been predicted to be sensitive to the three-body terms and, in this context, an experiment, aiming at the measurement of these lifetimes, was performed in GANIL in July 2017 with the AGATA and PARIS arrays coupled to the VAMOS++ magnetic spectrometer. Details on the AGATA preliminary data analysis are presented., National Science Centre, Poland (NCN) [2013/08/M/ST2/00257, 2014/14/M/ST2/00738, 2016/22/M/ST2/00269], This work was supported by the National Science Centre, Poland (NCN) under contracts No. 2013/08/M/ST2/00257, 2014/14/M/ST2/00738 and 2016/22/M/ST2/00269.

Zakopane Conference on Nuclear Physics - Extremes of the Nuclear Landscape -- AUG 26-SEP 02, 2018 -- Zakopane, POLAND, WOS: 000463866500051, An experiment aiming at measuring lifetimes of the second 2(+) excited states in neutron-rich C and O isotopes was recently performed at the GANIL laboratory, in France. In these nuclei, recent ab initio calculations provide a detailed description of the nuclear excited states, predicting a strong sensitivity of the electromagnetic transition probabilities to the details of the nucleon-nucleon interactions, especially in connection with the role played by the three-body (NNN) forces. Thus, the measurement of 2(+) states lifetimes in this region will be a stringent test of the importance of including the NNN forces in describing the electromagnetic properties of selected nuclear states. This contribution reports on the status of the experimental analysis for the case of lifetimes in O-20., European Union's Horizon 2020 through ENSAR2 grant [654002]; National Science Centre, Poland (NCN) [2013/08/M/ST2/00257, 2014/14/M/ST2/00738, 2016/22/M/ST2/00269]; COPININ2P3 collaboration, We acknowledge the important technical contributions of J. Goupil and the GANIL accelerator staff. The authors acknowledge support from the European Union's Horizon 2020 through ENSAR2 grant agreement No. 654002, the National Science Centre, Poland (NCN) Contract No. 2013/08/M/ST2/00257, 2014/14/M/ST2/00738 and 2016/22/M/ST2/00269 and COPININ2P3 collaboration.

The 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., 117

43rd Zakopane Conference on Nuclear Physics -- SEP 01-07, 2008 -- Zakopane, POLAND, WOS: 000264436200022, The PARIS project is ail initiative to develop and build a high-efficiency gamma-calorimeter principally for Use at SPIRAL2. It is intended to comprise a double shell of scintillators and use the novel scintillator material LaBr3(Ce), which promises a step-change in energy and time resolutions over what is achievable using conventional scintillators. The array could be used in a stand-alone mode, in conjunction with an inner particle detection system, or with high-purity germanium arrays. Its potential physics opportunities as well as initial designs and simulations will be discussed.